Do Personality Traits Predict Functional Impairment and Quality of Life in Adult ADHD? A Controlled Study

Abstract

Objective: To examine the association of personality traits and characteristics on quality of life and functioning in adults with ADHD. Method: Participants were adults with (n = 206) and without ADHD (n = 123) who completed the Temperament and Character Inventory (TCI), the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), and the Social Adjustment Scale–Self-Report (SAS-SR). Participants also provided information on academic, motor vehicle operation, legal, social, familial, and occupational functioning. Outcomes were examined using stepwise linear regression, logistic regression (for binary outcomes), and negative binomial regression (for count outcomes) controlling for ADHD symptoms, psychiatric comorbidity, and executive dysfunction. Results: Adults with ADHD significantly differed from controls across nearly all TCI personality domains. On average, adults with ADHD endorsed more novelty seeking, harm avoidance, and self-transcendence, and less reward dependence, persistence, self-directedness, and cooperativeness. Personality traits and characteristics, especially self-directedness, significantly predicted functional impairments even after controlling for ADHD symptoms, executive function deficits, and current psychiatric comorbidities. Conclusion: In adults with ADHD, personality traits exert unique associations on quality of life and functional impairment across major life domains, beyond the relations expected of and associated with ADHD symptoms and other associated psychiatric conditions and cognitive vulnerabilities. Addressing personality traits in adults with ADHD may lead to improvements in quality of life and reductions in functional impairment.

Keywords

ADHD adult ADHD personality quality of life functional impairment

ADHD is a neurodevelopmental disorder that affects an estimated 5% of adults in the United States (Faraone & Biederman, 2005; Kessler et al., 2006) and one that exacts a costly toll in productivity and income—estimated at US$87 to US$138 billion annually (Biederman & Faraone, 2006; Doshi et al., 2012). ADHD is frequently comorbid with other psychiatric disorders including disruptive behavior, and antisocial, mood, anxiety, and addictive disorders (Biederman et al., 1993; Miller, Nigg, & Faraone, 2007; Wilens et al., 2009), which are also associated with losses in health-related quality of life (Saarni et al., 2007).

Interest in examining social and functional impairments as well as quality of life in adults with ADHD has increased in the past 10 years (Biederman et al., 2008; Brod, Johnston, Able, & Swindle, 2006; Landgraf, 2007; Matza, Johnston, Faries, Malley, & Brod, 2007; Mick, Faraone, Spencer, Zhang, & Biederman, 2008). The adverse impact of ADHD on quality of life has been documented in terms of impairments in psychosocial functioning (Nijmeijer et al., 2008), reduced sleep quality (Kooij, Middelkoop, van Gils, & Buitelaar, 2001), lower subjective well-being (Gudjonsson, Sigurdsson, Eyjolfsdottir, Smari, & Young, 2009), poorer social adaptation (Sentissi et al., 2008), and cardiovascular risks (Spencer, Faraone, Tarko, McDermott, & Biederman, 2014). Executive dysfunction has been implicated as a source of functional impairment in adults with ADHD (Barkley & Murphy, 2010). Furthermore, adults with ADHD experience higher rates of psychiatric comorbidities relative to controls and the addition of psychiatric comorbidities also contribute to poorer functional outcomes in adults with ADHD (Sobanski et al., 2007).

Another potential source of functional impairment in adults with ADHD are personality traits. In children, ADHD symptoms have been linked to temperamental traits such as low reactive control, low resiliency, and poor effortful control (Martel & Nigg, 2006). In addition, the severity of childhood ADHD symptoms have been negatively linked with self-directedness (Cho et al., 2008), defined by Cloninger as the ability to self-regulate and adapt behavior in the pursuit of one’s chosen goals (Cloninger, Svrakic & Przybeck, 1993). The persistence of ADHD from childhood to adolescence has also been linked to higher neuroticism and lower conscientiousness (Miller, Miller, Newcorn, & Halperin, 2008). In the adult ADHD literature, consistent associations between ADHD symptoms and personality traits and disorders have been documented (Faraone, Kunwar, Adamson, & Biederman, 2009; Jacob et al., 2007; Nigg et al., 2002). Adults with ADHD show higher levels of novelty seeking and harm avoidance (Anckarsater et al., 2006) and comorbidities with personality disorders such as borderline personality disorder (BPD; van Dijk, Lappenschaar, Kan, Verkes, & Buitelaarf, 2012).

Much of the extant ADHD and personality literature has been informed by Cloninger’s tridimensional theory of personality, which posits that personality is comprised of three dimensions of character—self-directedness, cooperativeness, and self-transcendence, and four dimensions of temperament—harm avoidance, novelty seeking, reward dependence, and persistence (Cloninger, 1994; Cloninger, Svrakic, & Przybeck, 1993). Specifically, self-directedness (SD), a character trait of being responsible and resourceful versus blaming and inept (Cloninger et al., 1993), has been implicated in several descriptive studies of adults with ADHD. For example, SD was shown to be lower in adults with ADHD compared with other clinical populations (Anckarsater et al., 2006) and lower in both late-onset and full threshold ADHD than subthreshold ADHD (Faraone et al., 2009). In this latter study, adults with ADHD who were lower in self-directedness tended to be less responsible, resourceful, and goal-oriented; they also tended to have more difficulty in defining, setting, and pursuing meaningful goals (Faraone et al., 2009).

In non-ADHD populations, self-directedness is positively associated with quality of life and functioning (Cloninger, 2006). One study of non-ADHD psychiatric outpatients showed that a significant portion of the variance in quality of life was explained by personality characteristics such as SD (Masthoff, Trompenars, Van Heck, Hodiamont, & De Vries, 2007). Less is known, however, about SD and its relation to quality of life or functional impairments in the context of adult ADHD. Whether personality traits continue to be associated with functional impairments and quality of life after eliminating the contributions of ADHD symptoms, executive dysfunction, and psychiatric comorbidities has also never been explored.

An implicit assumption in the literature on ADHD presumes that ADHD symptoms are to blame for functional impairments and detriments in quality of life (Gordon et al., 2006). However, by narrowly focusing on ADHD symptom reduction, researchers and clinicians alike may be ignoring other important contributing factors to social, functional, and treatment outcomes, such as personality characteristics. A better understanding of the impact that personality traits have on quality of life and functioning in adults with ADHD is therefore an area of high clinical significance. Crucially, existing adult ADHD interventions, whether pharmaco- or psychotherapeutic, largely target reductions in ADHD symptoms and psychiatric comorbidity (Rostain, Jensen, Connor, Miesle, & Faraone, 2015), not personality traits or character dimensions; this has gernally been due to the fact that past research has often overlooked personality traits as a possible predictor of functional impairments. Thus, the extent to which personality traits should be considered and incorporated into existing adult ADHD assessment or nonpharmacological interventions remains unknown.

The current investigation attempts to fill important voids in the adult literature by examining the association of personality traits and character dimensions on functional outcomes and quality of life in adults with ADHD, after removing the contribution of ADHD symptoms, executive function deficits, and psychiatric comorbidities. Based on the existing literature documenting the predictive power of self-directedness in non-ADHD populations, we hypothesized that self-directedness would significantly predict quality of life and functional impairment in adults with ADHD, even after controlling for symptoms of ADHD. Our goal in this study is to investigate the association of personality traits, not personality disorders, on functioning and quality of life. In this way, we hope to provide information on the broader population of adults with ADHD, not solely adults with ADHD who have comorbid personality disorders.

Method

Participants

Males and females ages 18 to 55 were eligible to participate in the current study. Participants were excluded if they had major sensorimotor handicaps (deafness, blindness), psychosis, inadequate command of English, or a Full-Scale IQ lower than 80. Two ascertainment sources were employed to recruit participants with ADHD: clinical referrals to psychiatric clinics at the Massachusetts General Hospital (MGH; clinical subsample; n = 185) and advertisements in the greater Boston area (community subsample; n = 21). We recruited all potential non-ADHD participants (n = 123) through advertisements in the greater Boston area. The two groups did not differ significantly by gender or race/ethnicity; however, mean Hollingshead-defined socioeconomic status (1 = highest SES, 5 = lowest SES) was significantly different between the two groups, χ²(4) = 22.85, N = 312, p < .001, with the ADHD group reporting lower mean SES than the control group, t(310) = 3.74, p < .001. For complete demographic information on participants, please see Table 1. For both groups, a stringent three-stage ascertainment process was used. Detailed study methodology has been previously described (Antshel et al., 2010; Faraone et al., 2009; Surman et al., 2011). After receiving a complete description of the study, the participants provided written informed consent. The institutional review board granted approval for this study.

Table 1.

Sample Characteristics of Participants With and Without ADHD.

	M (SD)		t	df
	Control	ADHD
	(n = 123)	(n = 206)
1. Age	29.78 (8.72)	36.27 9 (10.75)	−5.67***	327
2. % male	46	51	−0.95	327
3. % White	86	84	−1.41	175
4. GAF	68.19 (4.75)	56.89 (7.13)	15.61***	327
5. Q-LES-Q overall life satisfaction	4.14 (0.63)	3.22 (1.07)	8.28***	296
6. SAS-SR overall social adjustment	51.66 (8.25)	67.98 (14.70)	−10.96***	299
7. FES family expressiveness	55.32 (13.85)	46.22 (14.33)	5.16***	270
8. FES family conflict	42.58 (9.76)	50.18 (13.01)	−5.11***	270
9. FES family cohesion	57.20 (14.18)	46.31 (18.26)	5.19***	271

Note. GAF = Clinician’s Rating of Global Assessment of Functioning; Q-LES-Q = Quality of Life Enjoyment and Satisfaction Questionnaire; SAS-SR = Social Adjustment Scale–Self-Report; FES = Family Environment Scale.

***

p < .001.

Assessment Measures

Diagnostic

We interviewed all participants with the Structured Clinical Interview for DSM-IV (SCID-I) to determine ADHD status. Initial diagnoses were prepared by the study interviewers and were then reviewed by a diagnostic committee of board-certified psychiatrists or licensed psychologists. The diagnostic committee was blind to the participant’s ascertainment group and all nondiagnostic data (e.g., cognitive functioning). Diagnoses were made for two points in time: lifetime and current (past month) in accordance with all Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) criteria for ADHD. The SCID-I was supplemented with modules from the Schedule for Affective Disorders and Schizophrenia for School-Age Children Epidemiologic Version adapted for DSM-IV (K-SADS-E; Orvaschel, 1994) to cover ADHD and other disruptive behavior disorders. On the K-SADS-E, participants were first queried about childhood ADHD and disruptive behavioral disorder symptoms, and if they were present, were asked about continuation of these symptoms into adulthood and the emergence of others. Age at onset was defined as the first emergence of impairing symptoms. The current number of ADHD symptoms was derived from the participants’ responses on the K-SADS-E and only included those symptoms that were endorsed at threshold levels (occurring “often”; possible range 0-18 symptoms). After reviewing all assessment data, definite ADHD diagnoses were assigned to participants who met all DSM-IV diagnostic criteria for ADHD. The number of psychiatric comorbidities as indicated by the SCID-I and self-report was also documented.

Functional outcomes

The structured interview also addressed functional domains such as academics (e.g., highest grade completed, number of grades repeated, history of special education programming), motor vehicle operation (e.g., number of traffic accidents, number of speeding tickets), and legal/criminal activity (e.g., history of ever having been arrested) to determine functional impairment. A dichotomous categorization (Yes/No) was utilized for many of the psychosocial history questions (e.g., history of arrests, etc.).

Quality of life

Quality of life was assessed with the short-form version of the original Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q-SF; Endicott, Nee, Harrison, & Blumenthal, 1993). The Q-LES-Q-SF is a 16-item self-report instrument that evaluates enjoyment and satisfaction in various areas of daily functioning, including physical health, work, social relationships, family, and general activities, and has been validated for use in an adult ADHD population (Mick et al., 2008). Each item is scored using a 5-point Likert-type scale (1 = very poor, 5 = very good) where higher scores indicate greater enjoyment and satisfaction. The Q-LES-Q-SF is a commonly used and a well-validated tool with good test–retest reliability and high internal consistency (Bishop, Walling, Dott, Folkes, & Bucy, 1999; Mick et al., 2008; Schechter, Endicott, & Nee, 2007).

Social adjustment

Social functioning was assessed using the Social Adjustment Scale–Self-Report (SAS-SR; Weissman & Bothwell, 1976), a 54-item Likert-type scale self-report instrument that quantifies an individual’s level of satisfaction with his or her social situation using seven major areas: work/school, social and leisure, relationships with extended family, primary relationship, parental role, family unit, and overall social adjustment, with higher scores indicating more social maladjustment. Scores for each role area were converted to a sex-corrected T-score (M = 50) based upon published norms from the administration manual. The administration manual suggests that T-scores > 65 are indicative of “clinically significant” impairment. The SAS-SR has been used in intervention research to determine changes in social outcomes and social functioning beyond symptoms (Reay et al., 2006). The SAS-SR has been shown to be a valid measure of functional status and is widely used both clinically and in academic research (Weissman, Olfson, Gameroff, Feder, & Fuentes, 2001).

Family functioning

Family functioning was assessed using the Family Environment Scale (FES; Moos & Moos, 1994). The FES is a 90-item true/false instrument designed to assess the social and environmental characteristics of a family, including three interpersonal relationship factors: (a) cohesion, the degree of commitment and support family members provide for each other; (b) expressiveness, the degree to which family members are encouraged to express their feelings openly with each other; and (c) conflict, the degree to which family members openly express anger and aggression toward each other. The FES is a well-validated tool with good reliability and consistency, which has been used in research on child and family studies of ADHD (Faraone et al., 1995; Pressman et al., 2006; Schroeder & Kelley, 2009). Previous research with the FES shows that parents of children with ADHD rate their families as higher in conflict than controls (Pressman et al., 2006).

Personality

The Temperament and Character Inventory (TCI) is a questionnaire that assesses four temperament dimensions (Novelty Seeking, and Harm Avoidance, Reward Dependence and Persistence) and three character dimensions (Self-Directedness, Cooperativeness, and Self-Transcendence). We administered the TCI-144, a 144-question condensed version of the TCI-295 that uses the 20 best predictors from each personality dimension (Cloninger, 1987; Svrakic, Whitehead, Przybeck, & Cloninger, 1993) and is answered on a 5-point Likert-type scale from definitely false to definitely true.

Novelty seeking represents impulsivity in decision making and sensation seeking behaviors. Harm avoidance reflects anticipatory anxiety and a tendency to respond strongly to aversive stimuli. Reward dependence represents a tendency to respond intensely to reinforcement and a dependence on approval of others. Persistence reflects perseverance in the face of aggravation. Self-directedness refers to the ability to engage in problem solving, goal-directed behaviors. Cooperativeness represents traits such as empathy, compassion, and helpfulness. Self-transcendence reflects the ability to accept ambiguity and identification with the wider world.

Binary measure of executive dysfunction

As part of the study procedures, multiple psychological tests were administered including several tests that assess executive functioning. Two subtests from the Wechsler Adult Intelligence Scale–Third Edition (WAIS-III; Wechsler, 1993), Arithmetic and Digit Span, were administered as well as the Wisconsin Card Sorting Test (Heaton, Chelune, Talley, Kay, & Curtiss, 1993), the Stroop Color and Word Test (Golden, 1978), the California Verbal Learning Test (Delis, Kramer, Kaplan, & Ober, 1987), and the Seidman auditory working memory continuous performance task (Seidman et al., 1998).

Using a method with precedence in the literature (Biederman et al., 2006), we computed a binary measure of deficits of executive dysfunction. For each of the executive functioning dependent variables, we defined poor performance as a score <1.5 standard deviations from the mean for normally distributed variables or within the poorest 7th percentile of performance for nonnormally distributed variables. We then created binary impairment indicators for the executive function variables for all participants (ADHD and control). Thus, we could sum the number of variables (range = 0-6) for which any given participant performed poorly based on the cutoffs.

Data Analyses

Planned analyses

All statistical analyses were conducted using SPSS for Mac Version 22. Initially, we conducted descriptive statistics on demographic and functional variables to better understand the samples. Next, we conducted an omnibus MANCOVA on the dependent variables from the seven TCI personality traits. If this analysis was significant, follow-up univariate ANCOVA tests were planned.

Following these descriptive analyses, and to assess our a priori hypotheses, a series of planned stepwise linear regressions were computed using functional outcomes as the dependent variables. Initially, ADHD symptoms were entered into the linear regression. Current levels of ADHD symptoms were obtained from the participants’ report on the K-SADS-E. As not all participants had executive function deficits and current psychiatric comorbidities, these variables were entered simultaneously in the second step as covariates. In the third step, each of the TCI personality traits was entered simultaneously. In this way, we could assess the independent contribution of TCI personality traits on Quality of Life Enjoyment and Satisfaction (QLES) after controlling for ADHD symptoms, executive function deficits, and current psychiatric comorbidities. With regard to modeling binary functional outcome variables (e.g., history of arrests), binary logistic regressions were planned using a three-step process of entering ADHD symptoms in the first step, executive function deficits and current psychiatric comorbidities in the second step, and each of the TCI personality traits in the third step. With regard to modeling functional count outcome variables that were overdispersed (e.g., number of speeding tickets), negative binomial regressions were planned, with functional outcomes as dependent variables and TCI personality traits, ADHD symptoms, executive function deficits, and current psychiatric comorbidities as independent variables. Given the exploratory nature of this work, we did not apply a Bonferroni correction.

All of the aforementioned analyses were also conducted with the control group. As with the ADHD group, both the number of executive function deficits and the number of current comorbidities were controlled for. However, ADHD symptoms were taken out of the regression models as members of the control group did not report on ADHD symptoms.

Results

As reported elsewhere (Faraone et al., 2006; Mick et al., 2008), Table 1 documents the worse family functioning, worse social functioning, and lower quality of life of the ADHD group compared with the controls. The omnibus MANCOVA on the seven TCI personality traits was significant, Wilks’s λ = 0.56, F(7, 293) = 33.57, p < .001, η² = .45. Follow-up univariate ANCOVA’s revealed ADHD versus control differences on all TCI personality traits except for one character dimension, Self-Transcendence, F(1, 299) = 2.36, p = .125. See Table 2 for complete TCI data on group differences between adults with ADHD and controls.

Table 2.

TCI Group Differences in Adults With ADHD Versus Controls.

TCI dimensions	Control (n = 118)	ADHD (n = 184)	t
TCI dimensions	M (SD)	M (SD)	t
1. Novelty seeking	53.02 (7.15)	63.96 (9.69)	−10.56***
2. Harm avoidance	52.77 (9.94)	60.01 (13.49)	−5.02***
3. Reward dependence	71.97 (9.41)	67.20 (11.16)	3.84***
4. Persistence	72.94 (9.92)	63.31 (11.78)	7.36***
5. Self-directedness	80.32 (9.33)	61.39 (13.88)	13.04***
6. Cooperativeness	80.26 (9.17)	74.52 (11.04)	4.71***
7. Self-transcendence	48.81 (16.32)	52.41 (16.54)	−1.85

Note. All df = 300. TCI = Temperament and Character Inventory.

***

p < .001.

In the ADHD group, the temperament dimension of TCI Novelty Seeking predicted the total number of ADHD symptoms (β = .214, t = 2.69, p = .008); higher novelty seeking was associated with higher levels of ADHD symptoms. Other than this one significant finding, TCI personality traits did not predict any other ADHD clinical features including duration of ADHD symptoms, age at onset of ADHD treatment initiation, age at onset of impairing ADHD symptoms, and past/current number of ADHD symptoms (all ps > .05).

Impact of TCI Personality Variables on Functional Outcomes in Adults With ADHD

After controlling for ADHD symptoms, executive function deficits, and psychiatric comorbidities, TCI personality traits did not predict educational functional outcomes such as highest grade completed, need for academic supports/tutoring, having repeated a grade and being involved in special education programming. Personality traits additionally did not predict number of traffic accidents, but TCI Reward Dependence did predict number of speeding tickets, β = −.031, p = .022; lower levels of reward dependence was associated with higher number of speeding tickets in participants with ADHD.

TCI Cooperativeness, Wald (1) = 8.16, p = .004, odds ratio (OR) = .942, and TCI Novelty Seeking, Wald (1) = 7.47, p = .006, OR = 1.06, remained significantly associated with lifetime incidence of ever being arrested after controlling for ADHD symptoms, executive function deficits, and psychiatric comorbidities. Lower levels of cooperativeness and higher levels of novelty seeking traits were associated with being arrested in participants with ADHD. None of the other TCI variables predicted lifetime incidence of ever being arrested (all p > .05).

Impact of TCI Personality Variables on Functional Outcomes in Control Participants (Adults Without ADHD)

After controlling for executive function deficits and number of current psychiatric comorbidities, TCI personality variables did not predict number of motor vehicle accidents or number of tickets. Furthermore, TCI personality variables did not predict educational functional outcomes such as need for academic supports tutoring and being involved in special education programming. However, TCI Cooperativeness predicted having to repeat a grade in the past (β = −.576, t = − 3.66, p = .001); lower levels of cooperativeness were associated with academically repeating a grade in control participants. TCI Reward Dependence predicted highest grade completed (β = −.335, t = − 2.06, p = .045); lower levels of reward dependence were associated with progressing further in school in control participants.

Impact of TCI Personality Variables on Social and Family Adjustment in Adults With ADHD

All of these analyses included total number of DSM-IV ADHD symptoms, executive function deficits, and psychiatric comorbidities as covariates. With regard to social adjustment outcomes as measured by the SAS-SR, only TCI Self-Directedness predicted SAS-SR Work (β = − .211, t = − 1.79, p = .05) and SAS-SR Primary Relationship (β = − .506, t = − 3.19, p = .002) adjustment. Lower levels of self-directedness predicted more impaired work and primary relationship functioning in our ADHD sample. TCI Harm Avoidance also predicted SAS-SR Primary Relationship adjustment (β = − .266, t = − 2.18, p = .03). Lower levels of harm avoidance predicted more impaired primary relationship functioning in our ADHD sample. Finally, TCI Cooperativeness predicted SAS-SR Family Unit adjustment (β = − .232, t = − 2.12, p = .04). Lower levels of cooperativeness predicted more impaired family functioning in our ADHD sample. None of the TCI personality dimensions significantly predicted SAS-SR Parenting adjustment.

With regard to Social/Leisure Time adjustment, TCI Harm Avoidance (β = .305, t = 4.61, p < .001), TCI Novelty Seeking (β = .124, t = 2.04, p = .04), TCI Reward Dependence (β = − .256, t = − 4.06, p < .001), and TCI Self-Directedness (β = − .369, t = − 4.63, p < .001) emerged as significant predictors. Higher levels of harm avoidance and novelty seeking as well as lower levels of reward dependence and self-directedness predicted more impaired social/leisure functioning in our ADHD sample.

With respect to Extended Family adjustment, TCI Self-Directedness (β = − .237, t = − 2.50, p = .01) emerged as a significant predictor; lower levels of self-directedness were associated with more impaired extended family functioning in our ADHD sample. With respect to Overall Social Adjustment, TCI Harm Avoidance (β = .219, t = 3.52, p = .001), TCI Reward Dependence (β = − .153, t = − 2.58, p = .011), and TCI Self-Directedness (β = − .441, t = − 5.89, p < .001) emerged as significant predictors. Higher levels of harm avoidance and lower levels of reward dependence and self-directedness were associated with more impaired overall social adjustment in our ADHD sample.

With regard to self-report of family functioning, only one TCI variable predicted FES Expressiveness: TCI Reward Dependence (β = .240, t = 2.59, p = .011). Higher reward dependence was associated with higher levels of expressiveness in the family in our ADHD sample. No TCI personality traits predicted FES Conflict or FES Cohesion.

Impact of TCI Personality Variables on Social and Family Adjustment in Control Participants (Adults Without ADHD)

Only TCI Harm Avoidance significantly predicted SAS-Social/Leisure activities (β = .535, t = 3.14, p = .003). Higher levels of harm avoidance were predictive of higher perceived social/leisure impairment in our control sample. None of the TCI variables predicted any other SAS domain.

Only TCI Self-Directedness (β = 427, t = 2.03, p = .05) significantly predicted FES Expression. Higher levels of self-directedness were predictive of more family expressiveness in our control sample. No TCI variables significantly predicted FES Conflict. Self-Directedness (β = .525, t = 2.90, p = .007) and Self-Transcendence (β = .375, t = 2.75, p = .01) predicted FES Cohesion. Higher levels of self-directedness and self-transcendence predicted higher levels of family cohesion in our control sample.

Impact of TCI Personality Variables on Quality of Life in Adults With ADHD

All of these analyses included total number of DSM-IV ADHD symptoms, executive function deficits, and current psychiatric comorbidities as covariates. Only TCI Self-Directedness (β = .509, t = 6.22, p < .001) was a significant predictor of total self-report of Overall Life Satisfaction on the Q-LES-Q-SF. Higher levels of self-directedness were predictive of higher reported quality of life. When all of the 16 Q-LES-Q-SF were collapsed into a single composite variable (i.e., the 16 variables were summed and averaged), TCI Self-Directedness (β = .590, t = 5.26, p < .001) and TCI Cooperativeness (β = −.265, t = −2.73, p = .009) emerged as significant predictors of the composite average Q-LES-Q-SF quality of life variable. Higher self-directedness and lower cooperativeness predicted higher quality of life in our ADHD sample. Indeed, TCI Self-Directedness emerged as the clearest and strongest predictor of Q-LES-Q-SF variables in our ADHD sample, predicting 14 of the 16 domains. Please see Supplementary Figure 1 for TCI Self-Directedness and Q-LES-Q-SF relationships.

Impact of TCI Personality Variables on Quality of Life in Control Participants (Adults Without ADHD)

TCI Self-Directedness (β = .381, t = 2.29, p = .027) and Reward Dependence (β = −.310, t = −2.38, p = .022) predicted Q-LES-Q-SF Overall Life Satisfaction. Greater self-directedness and lower levels of reward dependence predicted higher overall life satisfaction in the control group. When all of the 16 Q-LES-Q-SF were collapsed into a single composite variable, none of the TCI variables significantly predicted the composite Q-LES-Q-SF quality of life variable in the control group.

Discussion

An implicit assumption in the literature presumes that ADHD symptoms are to blame for functional impairments and detriments in quality of life (Gordon et al., 2006); this assumption in turn influences treatment guidelines that focus on symptom reduction as the primary goal of treatment (Rostain et al., 2015). However, by solely focusing on ADHD symptom reduction, researchers and clinicians alike may be ignoring an important contributing factor to functional outcomes, namely, personality characteristics.

Even after controlling for ADHD symptoms, executive function deficits, and psychiatric comorbidities, in both ADHD and control groups, self-directedness predicted multiple functional outcomes and quality of life domains in the anticipated direction: Lower self-directedness predicted poorer outcomes and functioning. Lower self-directedness also predicted more impairments in social functioning; as expected, lower self-directedness predicted poorer adjustment in work, family, and social relationships. A more curious finding that is specific to the ADHD group is that lower levels of cooperativeness were predictive of higher self-reported quality of life. Future research should attempt to replicate this finding prior to speculating on what this association may imply.

Other TCI personality characteristics (i.e., reward dependence, harm avoidance, novelty seeking, and cooperativeness) also predicted several quality of life and functional impairment indices. For example, adults with ADHD who were less cooperative and more novelty seeking had a significantly higher likelihood of ever being arrested. However, after controlling for ADHD symptoms, executive functioning deficits, and psychiatric comorbidities, none of the TCI personality variables were related to educational outcomes such as highest grade completed or motor vehicle outcomes such as number of traffic accidents or tickets.

Whether or not self-directedness or any other personality traits are malleable to the effects of learning or intervention remains an open question to be investigated in future research. In one randomized pharmacological treatment trial with a 6-month follow-up, depressed patients with BPD experienced improvements in depression alongside clinically significant improvement of more than one standard deviation in self-directedness during the course of treatment (Joyce et al., 2003). While intriguing, these results are preliminary and not necessarily specific to ADHD—more research is needed to elucidate the malleability of personality traits implicated in adults with ADHD. However, these preliminary findings offer promise that personality characteristics may be amenable to change with appropriate therapeutic intervention.

Furthermore, the question of whether personality factors have clinical implications for both assessment and the direction of treatment in adults with ADHD is a topical concern (Gomez & Corr, 2014). If indeed adults with ADHD consistently exhibit lower levels of self-directedness compared with matched controls, then measures of self-directedness could be potentially incorporated into the assessment of ADHD. One genetic study of ADHD found that personality predicted lifetime ADHD status, accounting for 49% of the variance, with novelty seeking (R² = .26) representing the primary force driving the association (Lynn et al., 2005). Similarly, our data suggest that clinicians would be wise to be attuned to personality traits when attempting to predict functional impairments in adults with ADHD. Given that it is typically functional impairments, not symptoms, that drive adults to seek treatment (Lam, Filteau, & Milev, 2011; Zimmerman et al., 2006), this information is important to consider in treatment planning.

These findings, while novel and clinically significant, should be viewed in light of the limitations of the study. For the diagnosis of ADHD, we relied upon the self-report of adult participants, some of whom were clinically referred, and some of whom were not. Therefore, these results may not be generalizable to all adults with ADHD. Relatedly, for the assessment of functional outcomes and personality traits, we also relied on self-report. It remains an open question whether and how personality traits may become accentuated or attenuated over time, from either positive (e.g., good social adjustment, high family cohesion) or negative (e.g., getting arrested) interactions with the environment. More research on the course and stability of personality traits is needed to satisfactorily address these issues. Similarly, because all of the measures were self-report, the findings could be the results of method variance. Furthermore, we did not measure personality pathology in this population. The overlap in clinical features of ADHD and some personality disorders such as BPD are striking and have led some researchers to posit that ADHD and BPD may share a common neurobiological etiology (Philipsen, 2006). As we did not ascertain the presence of personality pathology, we could not control for its potential confounding associations in this study. Finally, given the exploratory nature of these analyses, we did not use a correction statistic such as a Bonferroni correction; thus, there remains the possibility of Type 1 errors.

Despite these limitations, this study is the first to demonstrate the adverse association of personality factors on quality of life and functional impairments in different life domains even after controlling for ADHD symptoms, executive function impairments and psychiatric comorbidities. Among personality domains, TCI self-directedness in particular emerged as an important and robust predictor of quality of life and functioning in adults with ADHD. Future research should strive to clarify these relationships and uncover the mechanisms by which personality may exert independent associations on quality of life and functional impairment. Furthermore, future research should consider the extent to which developing interventions that target and improve self-directedness may lead to improvements in the quality of life and functioning in adults with ADHD.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by funding from the National Institutes of Health (SVF).

Author Biographies

J. Allison He, MS, is a doctoral candidate in Clinical Psychology at Syracuse University. Her research interests center on improving the diagnostic process for ADHD across the lifespan and investigating the correlates and determinants of positive outcomes for ADHD.

Kevin M. Antshel, PhD, is an associate professor of Psychology and Director of Clinical Training for the Syracuse University Clinical Psychology doctoral program. His research interests focus on better understanding the heterogeneity of ADHD.

Joseph Biederman, MD, is the chief of the Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD, and director of the Alan and Lorraine Bressler Clinical and Research Program for Autism Spectrum Disorders, at Massachusetts General Hospital, Boston, MA. He is a professor of psychiatry at Harvard Medical School, Boston, MA.

Stephen V. Faraone, PhD, is the Director of the Medical Genetics Research Center and distinguished professor of psychiatry and neuroscience and physiology at SUNY Upstate Medical University, Syracuse, NY. In addition, he holds an honorary professorship at the K.G. Jebsen Centre for Research on Neuropsychiatric Disorders at the University of Bergen, Norway. He is also senior scientific advisor to the Pediatric Psychopharmacology and Adult ADHD program at Massachusetts General Hospital and a lecturer at Harvard Medical School, Boston, MA.

References

American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.

Anckarsater

Stahlberg

Larson

Hakansson

Jutblad

S. B.

Niklasson

. . . Rastam

(2006). The impact of ADHD and autism spectrum disorders on temperament, character, and personality development. American Journal of Psychiatry, 163, 1239-1244. doi:10.1176/appi.ajp.163.7.1239

Antshel

K. M.

Faraone

S. V.

Maglione

Doyle

A. E.

Fried

Seidman

L. J.

Biederman

(2010). Executive functioning in high-IQ adults with ADHD. Psychological Medicine, 40, 1909-1918. doi:10.1017/S0033291709992273

Barkley

Murphy

(2010). Impairment in occupational functioning and adult ADHD: the predictive utility of executive function (EF) ratings versus EF tests. Archives of Clinical Neuropsychology, 25, 157-173.

Biederman

Faraone

S. V.

(2006). The effects of attention-deficit/hyperactivity disorder on employment and household income. Medscape General Medicine, 8(3), 12.

Biederman

Faraone

S. V.

Spencer

Wilens

Norman

Lapey

K. A.

. . . Doyle

(1993). Patterns of psychiatric comorbidity, cognition, and psychosocial functioning in adults with attention deficit hyperactivity disorder. American Journal of Psychiatry, 150, 1792-1798. doi:10.1176/ajp.150.12.1792

Biederman

Petty

C. R.

Fried

Doyle

A. E.

Mick

Aleardi

. . . Faraone

S. V.

(2008). Utility of an abbreviated questionnaire to identify individuals with ADHD at risk for functional impairments. Journal of Psychiatric Research, 42, 304-310. doi:10.1016/J.Jpsychires.2006.12.004

Biederman

Petty

C. R.

Fried

Fontanella

Doyle

A. E.

Seidman

L. J.

Faraone

S. V.

(2006). Impact of psychometrically defined deficits of executive functioning in adults with attention deficit hyperactivity disorder. American Journal of Psychiatry, 163, 1730-1738.

Bishop

Walling

Dott

Folkes

Bucy

(1999). Refining quality of life: Validating a multidimensional factor measure in the severe mentally ill. Quality of Life Research, 8, 151-160.

10.

Brod

Johnston

Able

Swindle

(2006). Validation of the Adult Attention-Deficit/Hyperactivity Disorder Quality-of-Life Scale (AAQoL): A disease-specific quality-of-life measure. Quality of Life Research, 15, 117-129. doi:10.1007/s11136-005-8325-z

11.

Cho

S. C.

Hwang

J. W.

Lyoo

I. K.

Yoo

H. J.

Kin

B. N.

Kim

J. W.

(2008). Patterns of temperament and character in a clinical sample of Korean children with attention-deficit hyperactivity disorder. Psychiatry and Clinical Neurosciences, 62, 160-166. doi:10.1111/J.1440-1819.2008.01749.X

12.

Cloninger

C. R.

(1987). A systematic method for clinical description and classification of personality variants: A proposal. Archives of General Psychiatry, 44, 573-588.

13.

Cloninger

C. R.

(1994). Temperament and personality. Current Opinion in Neurobiology, 4, 266-273.

14.

Cloninger

C. R.

(2006). The science of well-being: An integrated approach to mental health and its disorders. World Psychiatry, 5(2), 71-76.

15.

Cloninger

C. R.

Svrakic

D. M.

Przybeck

T. R.

(1993). A psychobiological model of temperament and character. Archives of General Psychiatry, 50, 975-990.

16.

Delis

Kramer

J. H.

Kaplan

Ober

B. A.

(1987). CVLT: California Verbal Learning Test. San Antonio, TX: The Psychological Corporation.

17.

Doshi

J. A.

Hodgkins

Kahle

Sikirica

Cangelosi

M. J.

Setyawan

. . . Neumann

P. J.

(2012). Economic impact of childhood and adult attention-deficit/hyperactivity disorder in the United States. Journal of the American Academy of Child & Adolescent Psychiatry, 51, 990-1002.e2. doi:10.1016/j.jaac.2012.07.008

18.

Endicott

Nee

Harrison

Blumenthal

(1993). Quality of Life Enjoyment and Satisfaction Questionnaire: A new measure. Psychopharmacology Bulletin, 29, 321-326.

19.

Faraone

S. V.

Biederman

(2005). What is the prevalence of adult ADHD? Results of a population screen of 966 adults. Journal of Attention Disorders, 9, 384-391. doi:10.1177/1087054705281478

20.

Faraone

S. V.

Biederman

Spencer

Mick

Murray

Petty

. . . Monuteaux

M. C.

(2006). Diagnosing adult attention deficit hyperactivity disorder: Are late onset and subthreshold diagnoses valid? American Journal of Psychiatry, 163, 1720-1729; quiz 1859. doi:10.1176/appi.ajp.163.10.1720

21.

Faraone

S. V.

Chen

W. J.

Warburton

Biederman

Milberger

Tsuang

M. T.

(1995). Genetic-heterogeneity in attention-deficit hyperactivity disorder (ADHD)—Gender, psychiatric comorbidity, and maternal ADHD. Journal of Abnormal Psychology, 104, 334-345. doi:10.1037//0021-843x.104.2.334

22.

Faraone

S. V.

Kunwar

Adamson

Biederman

(2009). Personality traits among ADHD adults: Implications of late-onset and subthreshold diagnoses. Psychological Medicine, 39, 685-693. doi:10.1017/S0033291708003917

23.

Golden

J. C.

(1978). Stroop Color and Word Test. Chicago, IL: Stoelting.

24.

Gomez

Corr

P. J.

(2014). ADHD and personality: A meta-analytic review. Clinical Psychology Review, 34, 376-388. doi:10.1016/j.cpr.2014.05.002

25.

Gordon

Antshel

Faraone

Barkley

Lewandowski

Hudziak

J. J.

. . . Cunningham

(2006). Symptoms versus impairment: The case for respecting DSM-IV’s criterion D. Journal of Attention Disorders, 9, 465-475. doi:10.1177/1087054705283881

26.

Gudjonsson

G. H.

Sigurdsson

J. F.

Eyjolfsdottir

G. A.

Smari

Young

(2009). The relationship between satisfaction with life, ADHD symptoms, and associated problems among university students. Journal of Attention Disorders, 12, 507-515. doi:10.1177/1087054708323018

27.

Heaton

R. K.

Chelune

G. J.

Talley

J. L.

Kay

G. G.

Curtiss

(1993). Wisconsin Card Sorting Test manual: Revised and expanded. Odessa, FL: Psychological Assessment Resources.

28.

Jacob

C. P.

Romanos

Dempfle

Heine

Windemuth-Kieselbach

Kruse

. . . Lesch

K. P.

(2007). Co-morbidity of adult attention-deficit/hyperactivity disorder with focus on personality traits and related disorders in a tertiary referral center. European Archives of Psychiatry & Clinical Neuroscience, 257, 309-317. doi:10.1007/S00406-007-0722-6

29.

Joyce

P. R.

Mulder

R. T.

Luty

S. E.

McKenzie

J. M.

Sullivan

P. F.

Cloninger

R. C.

(2003). Borderline personality disorder in major depression: Symptomatology, temperament, character, differential drug response, and 6-month outcome. Comprehensive Psychiatry, 44, 35-43. doi:10.1053/comp.2003.50001

30.

Kessler

R. C.

Adler

Barkley

Biederman

Conners

C. K.

Demler

. . . Zaslavsky

A. M.

(2006). The prevalence and correlates of adult ADHD in the United States: Results from the National Comorbidity Survey Replication. American Journal of Psychiatry, 163, 716-723. doi:10.1192/bjp.bp.107.048827

31.

Kooij

J. J.

Middelkoop

H. A.

van Gils

Buitelaar

J. K.

(2001). The effect of stimulants on nocturnal motor activity and sleep quality in adults with ADHD: An open-label case-control study. Journal of Clinical Psychiatry, 62, 952-956.

32.

Lam

R. W.

Filteau

M. J.

Milev

(2011). Clinical effectiveness: The importance of psychosocial functioning outcomes. Journal of Affective Disorders, 132(Suppl. 1), S9-S13. doi:10.1016/j.jad.2011.03.046

33.

Landgraf

J. M.

(2007). Monitoring quality of life in adults with ADHD: Reliability and validity of a new measure. Journal of Attention Disorders, 11, 351-362. doi:10.1177/1087054707299400

34.

Lynn

D. E.

Lubke

Yang

McCracken

J. T.

McGough

J. J.

Ishii

. . . Smalley

S. L.

(2005). Temperament and character profiles and the dopamine D4 receptor gene in ADHD. American Journal of Psychiatry, 162, 906-913. doi:10.1176/appi.ajp.162.5.906

35.

Martel

M. M.

Nigg

J. T.

(2006). Child ADHD and personality/temperament traits of reactive and effortful control, resiliency, and emotionality. Journal of Child Psychology and Psychiatry, 47, 1175-1183. doi:10.1111/J.1469-7610.2006.01629.X

36.

Masthoff

E. D.

Trompenars

F. J.

Van Heck

G. L.

Hodiamont

P. P.

De Vries

(2007). The relationship between dimensional personality models and quality of life in psychiatric outpatients. Psychiatry Research, 149, 81-88. doi:10.1016/J.Psychres.2006.01.004

37.

Matza

L. S.

Johnston

J. A.

Faries

D. E.

Malley

K. G.

Brod

(2007). Responsiveness of the Adult Attention-Deficit/Hyperactivity Disorder Quality of Life Scale (AAQoL). Quality of Life Research, 16, 1511-1520. doi:10.1007/s11136-007-9254-9

38.

Mick

Faraone

S. V.

Spencer

Zhang

H. B. F.

Biederman

(2008). Assessing the validity of the Quality of Life Enjoyment and Satisfaction Questionnaire-Short Form in adults with ADHD. Journal of Attention Disorders, 11, 504-509. doi:10.1177/1087054707308468

39.

Miller

C. J.

Miller

S. R.

Newcorn

J. H.

Halperin

J. M.

(2008). Personality characteristics associated with persistent ADHD in late adolescence. Journal of Abnormal Child Psychology, 36, 165-173. doi:10.1007/s10802-007-9167-7

40.

Miller

T. W.

Nigg

J. T.

Faraone

S. V.

(2007). Axis I and II comorbidity in adults with ADHD. Journal of Abnormal Psychology, 116, 519-528. doi:10.1037/0021-843X.116.3.519

41.

Moos

R. H.

Moos

B. S.

(1994). Family Environment Scale manual. Santa Clara, CA: Consulting Psychologists Press.

42.

Nigg

J. T.

John

O. P.

Blaskey

L. G.

Huang-Pollock

C. L.

Willcutt

E. G.

Hinshaw

S. P.

Pennington

(2002). Big five dimensions and ADHD symptoms: Links between personality traits and clinical symptoms. Journal of Personality and Social Psychology, 83, 451-469. doi:10.1037//0022-3514.83.2.451

43.

Nijmeijer

J. S.

Minderaa

R. B.

Buitelaar

J. K.

Mulligan

Hartman

C. A.

Hoekstra

P. J.

(2008). Attention-deficit/hyperactivity disorder and social dysfunctioning. Clinical Psychology Review, 28, 692-708. doi:10.1016/j.cpr.2007.10.003

44.

Orvaschel

(1994). Schedule for Affective Disorders and Schizophrenia for School-Aged Children—Epidemiologic Version 5 (K-SADS-E). Ft. Lauderdale, FL: Nova Southeastern University.

45.

Philipsen

(2006). Differential diagnosis and comorbidity of attention-deficit/hyperactivity disorder (ADHD) and borderline personality disorder (BPD) in adults. European Archives of Psychiatry and Clinical Neuroscience, 256(Suppl. 1), i42-i46.

46.

Pressman

L. J.

Loo

S. K.

Carpenter

E. M.

Asarnow

J. R.

Lynn

McCracken

J. T.

. . . Smalley

S. L.

(2006). Relationship of family environment and parental psychiatric diagnosis to impairment in ADHD. Journal of the American Academy of Child & Adolescent Psychiatry, 45, 346-354. doi:10.1097/01.chi.0000192248.61271.c8

47.

Reay

Fisher

Robertson

Adams

Owen

Kumar

(2006). Group interpersonal psychotherapy for postnatal depression: A pilot study. Archives of Women’s Mental Health, 9, 31-39. doi:10.1007/s00737-005-0104-x

48.

Rostain

Jensen

P. S.

Connor

D. F.

Miesle

L. M.

Faraone

S. V.

(2015). Toward quality care in ADHD: Defining the goals of treatment. Journal of Attention Disorders, 19, 99-117. doi:10.1177/1087054712473835

49.

Saarni

S. I.

Suvisaari

Sintonen

Pirkola

Koskinen

Aromaa

Lonnqvist

(2007). Impact of psychiatric disorders on health-related quality of life: General population survey. British Journal of Psychiatry, 190, 326-332. doi:10.1192/Bjp.Bp.106.025106

50.

Schechter

Endicott

Nee

(2007). Quality of life of “normal” controls: Association with lifetime history of mental illness. Psychiatry Research, 152, 45-54.

51.

Schroeder

V. M.

Kelley

M. L.

(2009). Associations between family environment, parenting practices, and executive functioning of children with and without ADHD. Journal of Child and Family Studies, 18, 227-235. doi:10.1007/S10826-008-9223-0

52.

Seidman

L. J.

Breiter

H. C.

Goodman

J. M.

Goldstein

J. M.

Woodruff

P. W.

O’Craven

. . . Rosen

B. R.

(1998). A functional magnetic resonance imaging study of auditory vigilance with low and high information processing demands. Neuropsychology, 12, 505-518.

53.

Sentissi

Navarro

J. C.

De Oliveira

Gourion

Bourdel

M. C.

Bayle

F. J.

. . . Poirier

M. F.

(2008). Bipolar disorders and quality of life: The impact of attention deficit/hyperactivity disorder and substance abuse in euthymic patients. Psychiatry Research, 161, 36-42. doi:10.1016/j.psychres.2007.06.016

54.

Sobanski

Bruggemann

Alm

Kern

Deschner

Schubert

. . . Rietschel

(2007). Psychiatric comorbidity and functional impairment in a clinically referred sample of adults with attention-deficit/hyperactivity disorder (ADHD). European Archives of Psychiatry & Clinical Neuroscience, 257, 371-377. doi:10.1007/s00406-007-0712-8

55.

Spencer

T. J.

Faraone

S. V.

Tarko

McDermott

Biederman

(2014). Attention-deficit/hyperactivity disorder and adverse health outcomes in adults. Journal of Nervous and Mental Disease, 202, 725-731. doi:10.1097/NMD.0000000000000191

56.

Surman

C. B.

Biederman

Spencer

Yorks

Miller

C. A.

Petty

C. R.

Faraone

S. V.

(2011). Deficient emotional self-regulation and adult attention deficit hyperactivity disorder: A family risk analysis. American Journal of Psychiatry, 168, 617-623. doi:10.1176/appi.ajp.2010.10081172

57.

Svrakic

D. M.

Whitehead

Przybeck

T. R.

Cloninger

C. R.

(1993). Differential diagnosis of personality disorders by the seven-factor model of temperament and character. Archives of General Psychiatry, 50, 991-999.

58.

van Dijk

F. E.

Lappenschaar

Kan

C. C.

Verkes

R. J.

Buitelaarf

J. K.

(2012). Symptomatic overlap between attention-deficit/hyperactivity disorder and borderline personality disorder in women: The role of temperament and character traits. Comprehensive Psychiatry, 53, 39-47. doi:10.1016/J.Comppsych.2011.02.007

59.

Wechsler

(1993). Wechsler Adult Intelligence Scale—3rd edition. San Antonio, TX: The Psychological Corporation.

60.

Weissman

M. M.

Bothwell

(1976). Assessment of social adjustment by patient self-report. Archives of General Psychiatry, 33, 1111-1115.

61.

Weissman

M. M.

Olfson

Gameroff

M. J.

Feder

Fuentes

(2001). A comparison of three scales for assessing social functioning in primary care. American Journal of Psychiatry, 158, 460-466.

62.

Wilens

T. E.

Biederman

Faraone

S. V.

Martelon

Westerberg

Spencer

T. J.

(2009). Presenting ADHD symptoms, subtypes, and comorbid disorders in clinically referred adults with ADHD. Journal of Clinical Psychiatry, 70, 1557-1562. doi:10.4088/JCP.08m04785pur

63.

Zimmerman

McGlinchey

J. B.

Posternak

M. A.

Friedman

Attiullah

Boerescu

(2006). How should remission from depression be defined? The depressed patient’s perspective. American Journal of Psychiatry, 163, 148-150. doi:10.1176/appi.ajp.163.1.148