Quality of Life in Parents of Children with Attention-Deficit

Abstract

Objective: There is no study on the quality of life (QOL) of parents of children with attention-deficit–hyperactivity disorder (ADHD), although QOL is increasingly gaining more attention and the interactions between children and their parents are bi-directional. The aim of the present study was therefore to survey the QOL of parents of children with ADHD in Hong Kong, and explore the relationships of sociodemographic and clinical variables with QOL.

Method: Seventy-seven parents of children with ADHD were consecutively selected and the sociodemographic and clinical characteristics of the parents and their children were assessed.

Results: Compared with the general population in Hong Kong, significantly lower scores in physical, psychological, social and environmental QOL domains were found in the parents of children with ADHD. On multivariate analysis, for the children with ADHD, the severity of emotional and hyperactivity/inattention symptoms, and having a comorbid pervasive developmental disorder were significantly correlated with one or more domains of QOL; while for the parents, educational level, household monthly income and having major medical conditions were significantly correlated with one or more domains of QOL.

Conclusions: Parents of children with ADHD have low QOL and research is needed to understand the underlying problems.

Keywords

attention-deficit–hyperactivity disorder China quality of life

Attention-deficit–hyperactivity disorder (ADHD) is one of the most common childhood psychiatric disorders and is characterized by the core symptoms of inattention, hyperactivity and impulsivity with an early onset [1, 2]. The estimated prevalence of DSM-IV-defined ADHD is between 5% and 8% and that of ICD-10-defined ADHD is approximately 1.5% worldwide [3], while the corresponding figures among boys in Hong Kong were approximately 8.9% on the basis of DSM-III-R, and approximately 0.78% according to ICD-10 [4].

ADHD is a chronic and debilitating condition that could impact upon many aspects of a subject's life and cause significant academic, social, and emotional problems [5]. Preschool children with ADHD often present with excess motor restlessness, associated difficulties including delayed development, oppositional behaviour, and poor social skills [6, 7]. School-aged children with ADHD more frequently experience academic failure, rejection by peers, and low self-esteem [8]. In adolescence, children may develop further problems, including aggressive and antisocial behaviour, and at-risk behaviours [8]. In the past ADHD was assumed to gradually resolve after puberty [9], but recent longitudinal studies have suggested that ADHD can persist into adulthood [10], and as many as 60% of patients with ADHD symptoms in childhood continue to have problems in adult life, such as interpersonal difficulties with colleagues and employers and dismissal from employment, and they are at higher risk for drug and substance abuse and dependence [8].

In recent years quality of life (QOL) has emerged as an important outcome measure in guiding health care [11]. The World Health Organization (WHO) defined QOL as ‘an individual's perception of his/her position in life, in the context of the culture and value systems in which s/he lives, and in relation to goals, expectations, standards and concerns’ [12]. Preliminary evidence indicated that children and their parents have interrelated social and health needs [13], and the interactions between them are bi-directional [14]. For example, previous studies indicated that quality of the parents’ marital relationship, parenting stress and socioeconomic status were associated with behaviour problems in children 15–19; in contrast, children's mental problems could also lead to increased level of parenting stress, marital problems, role dissatisfaction and more frequent alcohol use for their parents [5], 20–22. Sawyer et al found that not only did children with psychiatric disorders including ADHD have a significantly poorer QOL than the healthy controls, their mental problems also interfered with the daily lives of their parents and families [23]. As a result, children's behaviour problems including ADHD could have a substantially negative influence on their parents’ QOL. To date, however, no study has explored the relationship between children's ADHD and their parents’ QOL.

The aims of the present study were therefore (i) to survey the QOL of parents of children with ADHD in Hong Kong; and (ii) to explore the relationships between sociodemographic and clinical variables and QOL.

Methods

Settings and subjects

The study was conducted between October 2007 and February 2008. A consecutive sample was used and the subjects were selected from a child follow-up psychiatric clinic of a university-affiliated district general hospital. All children participating in the present study were in treatment. The catchment area of the hospital covers a population of approximately 1. million. Parents of children with a diagnosis of ADHD according to DSM-IV were invited to take part in the study. The diagnosis of ADHD and any other comorbid psychiatric disorders were ascertained by scrutinizing medical records and confirming with the responsible psychiatrists. The assessment instruments were not used to assist in making the diagnoses. Exclusion criteria included (i) being non-Chinese; and (ii) having a child who is mentally handicapped. Mental handicap was defined as IQ <70 [24].

Assuming a medium effect size of 0.50 between the QOL of the parents and the general population in Hong Kong, with a power of 0.8 and significance level of 0.05 (one tailed), the sample size in the present study should be at least 64 according to Cohen's sample size tables [25].

Subjects meeting the study criteria were invited by the principal author (YT Xiang) to participate in the study on the day when they attended the clinic for routine follow up. Those who agreed to participate were asked to sign the consent form after they had been given a detailed explanation of the study.

Data collection

Sociodemographic and clinical data of children and their parents were collected from the children's clinic notes by the children's responsible clinician, and during face-to-face interview by the principal author (YT Xiang).

Assessment instruments

Hong Kong version of World Health Organization Quality of Life Schedule-Brief version

The World Health Organization Quality of Life Schedule–Brief version (WHOQOL-BREF) is a 26-item, self-administered generic questionnaire [26]. Subjects assess their satisfaction on each item during the past 2 weeks on a 5-point scale (from 1 = very dissatisfied to 5 = very satisfied). The 26 items can be divided into four subscales including physical health, psychological health, social relationships and environmental factors domains. The WHOQOL-BREF has well-established psychometric and cross-cultural properties and is sensitive to QOL changes. The scale has been widely used to assess QOL worldwide including Hong Kong [27].

Hong Kong version of the Strength and Difficulties Questionnaire

The Strength and Difficulties Questionnaire (SDQ) is a well-established and widely used screening instrument for psychopathology among children and adolescents. It consists of 25 statements relating to children's strengths and difficulties [28]. Each statement is rated on a 3-point scale (not true, somewhat true, certainly true). The 25 items are divided into five subscales: Conduct Problems, Emotional Problems, Hyperactivity, Peer Problems, and Prosocial Behaviour (each containing five items). Scores on the first four of these subscales are summed to provide a Total Difficulties score. The parent version of the SDQ was used in the present study and it has been validated for use among Chinese children in Hong Kong by two of the present authors (Lai et al.: unpublished data, 2009).

Hong Kong version of Strengths and Weaknesses of ADHD-Symptoms and Normal-Behaviour scale

The Strengths and Weaknesses of ADHD-Symptoms and Normal-Behaviour scale (SWAN) is an informant-rated questionnaire that contains 18 items to measure ADHD symptoms. Informants are asked to rate children's behaviours by comparing these with those of other children of the same age. The scores are rated on a 7-point scale, where negative scores indicate behaviours that are better than average, and positive scores indicate behaviours that are poorer than average (−3 = far above average, −2 = above average, −1 = somewhat above average, 0 = average, 1 = somewhat below average, 2 = below average, 3 = far below average) [29]. An individual's total score on the inattention and hyperactivity–impulsivity dimensions of the SWAN were then averaged to range from −3 to +3, with a negative score indicating a lower level of ADHD symptoms. The SWAN has been validated for use among Chinese children in Hong Kong by two of the current authors (Lai et al.: unpublished data, 2009).

Data analysis

Statistical analyses were performed using SPSS 13.0 (SPSS, Chicago, IL, USA). First, one-sample t-test was carried out to compare QOL rated in the present study with the norm of WHOQOL-BREF in Hong Kong. Second, the relationship between sociodemographic and clinical features and parents’ QOL domains was measured by means of Pearson correlation analysis when the data followed a normal distribution; otherwise Spearman rank correlation was used. Multiple regression using the stepwise method was used to identify factors affecting each of the QOL domains. Categorical variables were included as dummy variables. To avoid multicolinearity, tolerance was used to measure the strength of the linear relationships among the independent variables. In this case, ≥0.4 was regarded as acceptable. Two-tailed tests were used. Furthermore, a re-calculation of power based on the results was made using Cohen's criteria [25].

Ethical considerations

The research proposal was approved by the Joint Chinese University of Hong Kong–New Territories East cluster Clinical Research Ethics Committee in Hong Kong. All subjects involved had given written consent.

Results

A total of 98 parents of children with ADHD were approached, of whom 77 participated in the study. There were no significant difference between the participants and those refused in terms of basic sociodemographic characteristics (age and sex). Table 1 shows the sociodemographic data of the whole sample, and the sociodemographic and clinical data of the children with ADHD. Compared with the community norms of SWAN and SDQ from the validation studies (Lai et al.: unpublished data, 2009), the ADHD children in this study presented with more problems in SWAN inattention score (1.0±0.9 vs −0.2±1.0, p < 0.001), hyperactivity score (0.9±1.0 vs −0.6±1.0, p < 0.001), SDQ emotional symptoms (3.8±2.6 vs 2.5±2.0, p < 0.001), conduct problems (3.6±1.8 vs 2.1±1.6, p < 0.001), hyperactivity/inattention (7.2±2.1 vs 4.5±2.3, p < 0.001), peer problems (4.2±2.0 vs 2.6±1.7, p < 0.001) and total difficulties score (18.9±5.0 vs 11.7±5.4, p < 0.001), on one-sample t test.

Table 1.

Subject characteristics

	Mean	SD	n	%
Children (n = 77)
Age (years)	10.1	2.0
Sex (male)			61	79.2
Age when behaviours become a concern	5.3	2.6
Length of treatment (years)	2.4	1.9
Single child			26	33.8
Comorbid pervasive developmental disorder			13	16.9

Comorbid specific learning disability
SWAN-Inattention	1.0	0.9
SWAN-Hyperactivity/Impulsivity	0.9	1.0
SDQ-Emotional symptoms	3.8	2.6
SDQ-Conduct problems	3.6	1.8
SDQ-Hyperactivity/inattention	7.2	2.1
SDQ-Peer problems	4.2	2.0
SDQ-Prosocial behaviour	6.5	1.9
SDQ-Total difficulties	18.9	5.0

Parents (n = 77)
Age (years)	41.7	5.3
Sex (male)			13	16.9
Married			72	93.5
Educational level	10.6	4.6
Employed			33	42.9
Household monthly income (HKD)	19596	14380
Major medical conditions			13	16.9
History of lifetime psychiatric disorders			8	10.4

SDQ, Strength and Difficulties Questionnaire; SWAN, Strengths and Weaknesses of ADHD Symptoms and Normal Behaviours Questionnaire.

The parents’ QOL scores were significantly poorer when compared with the community norm in Hong Kong across all the four domains [30] (Table 2). Table 3 lists the statistically significant correlations of the different QOL domains. The age at which children's behaviours became a concern, scores on the emotional and hyperactivity/inattention subscales of the SDQ and presence of comorbid pervasive developmental disorder were correlated with one or more domains of the QOL. The presence of, or severity of, ADHD symptoms, however, did not impact on the parents’ QOL domains, nor did the duration of treatment. Among factors relating more specifically to the parents themselves, educational level, household income, being married and presence of major medical conditions were associated with one or more QOL domains.

Table 2.

QOL in parents vs Hong Kong general population

	Parents (n = 77)		General population (n = 155)
QOL domains	Mean	SD	Mean	SD	T statistics†	p
Physical	13.3	2.4	15.9	2.1	−9.4	<0.001
Psychological	13.4	2.1	14.8	2.4	−6.2	<0.001
Social	13.5	2.7	14.3	2.4	−2.7	0.009
Environmental	12.9	1.9	13.7	2.5	−3.5	0.001

QOL, quality of life. ^†One sample t-test.

Table 3.

Correlation of sociodemographic and clinical factors vs QOL domains

Item	Physical	Psychological	Social	Environmental
Child
Age	−0.11	−0.15	−0.01	−0.07
Sex	0.05	0.11	0.20	0.02
Age when behaviour become a concern	−1.1	−0.23∗	0.10	−0.10
Length of treatment	−0.03	−0.01	−0.02	0.05
Single child	0.14	0.03	−0.03	0.01
Comorbid pervasive developmental disorder	0.19	0.05	−0.05	0.25∗
Comorbid specific learning disability	−0.02	−0.03	0.12	0.53
SWAN-Inattention	−0.08	−0.01	0.22	−0.17
SWAN-Hyperactivity/Impulsivity	0.05	−0.06	0.20	−0.20
SDQ-Emotional symptoms	−0.33∗∗	−0.13	−0.27∗	−0.01
SDQ-Conduct problems	−0.01	0.02	0.08	−0.03
SDQ-Hyperactivity/inattention	0.13	0.17	0.29∗	−0.02
SDQ-Peer problems	−0.18	−0.01	−0.16	0.02
SDQ-Prosocial behaviour	−0.06	−0.04	0.05	−0.05
SDQ-Total difficulties	−0.20	0.01	−0.06	−0.02

Parent
Age	−0.13	−0.12	−0.10	−0.15
Sex (male)	0.06	−0.01	−0.02	0.10
Married	0.16	0.19	0.16	0.29∗
Years of formal educational	0.31∗∗	0.31∗∗	0.09	0.21
Employed status	0.13	0.22	0.17	0.18
Household monthly income (HKD)	0.08	0.21	0.002	0.49∗∗
Major medical conditions	−0.33∗∗	−0.18	−0.15	−0.18
History of lifetime psychiatric disorders	−0.12	−0.06	−0.20	−0.12

QOL, quality of life; SDQ, Strength and Difficulties Questionnaire; SWAN, Strengths and Weaknesses of ADHD Symptoms and Normal Behaviours Questionnaire. Only statistically significant independent variables are reported. ∗p < 0.05; ∗∗p < 0.01.

Results of multiple regression using the stepwise method to explore the independent correlates of QOL are listed in Table 4. All variables that had a significant bivariate correlation to QOL, that is, age when the children's behaviours became a concern; presence of a comorbid pervasive developmental disorder; emotional and hyperactivity/inattention symptoms of the children with ADHD; educational level, household monthly income; being married and presence of major medical conditions of the parents, were entered as independent variables and each QOL domain was entered as a dependent variable. All QOL domains were significantly predicted by one or more sociodemographic or clinical characteristics. Specifically, physical QOL was significantly predicted by presence of major medical conditions or a comorbid pervasive developmental disorder, educational level and emotional symptoms (F_(4,71)=6.99, p < 0.001), which accounted for 24% of the variance. Psychological QOL was significantly predicted by educational level (F_(1,75)=8.0, p = 0.006), which accounted for 7% of the variance. Social QOL was significantly predicted by presence of major medical conditions and hyperactivity/inattention symptoms (F_(2,74)=11.1, p < 0.001), accounting for 21% of the variance. Environmental QOL was significantly predicted by household monthly income and presence of comorbid pervasive developmental disorder (F_(2,74)=17.60, p < 0.001), accounting for 30% of the variance.

Table 4.

Stepwise multiple regression for QOL and demographic and clinical variables in Hong Kong^†

Dependent variable		Correlates	β	t	p
Physical QOL	Adjusted R²=0.24	Major medical conditions	−0.28	−2.67	0.009
	F_(4,71)=6.99,	Educational level	0.22	2.14	0.03
	p < 0.001	Comorbid pervasive developmental disorder	0.23	2.23	0.03
		SDQ-Emotional symptoms	−0.22	−2.10	0.04

Psychological QOL	Adjusted R²=0.07 F_(1,75)=8.0, p = 0.006	Educational level	0.31	2.83	0.006
Social QOL	Adjusted R²=0.21	Major medical conditions	−0.39	−3.78	<0.001
	F_(2,74)=11.10, p < 0.001	SDQ-Hyperactivity/inattention	0.32	3.09	0.003

Environmental QOL	Adjusted R²=0.30	Household month income	0.51	5.31	<0.001
	F_(2,74)=17.60, p < 0.001	Comorbid pervasive developmental disorder	0.29	2.98	0.004

QOL, quality of life. ^†Only statistically significant correlates are reported.

Based on the differences between the participants and the general population in Hong Kong in the four QOL domains, using Cohen's method [25], the average power achieved in the present study was 0.82 (one-tailed).

Discussion

To the best of our knowledge, this is the first study exploring QOL and its sociodemographic correlates in parents of children with ADHD.

As expected, the children in the present study had more severe ADHD symptoms (SWAN scores) and general psychopathology (SDQ scores) in comparison with the community norms, and their parents had significantly poorer scores in physical, psychological, social and environmental QOL domains compared with the general population in Hong Kong.

Johnston and Mash reported that the presence of ADHD could lead to increased likelihood of disturbances to family and marital functioning, reduced parenting efficacy, disrupted parent–child relationships, and increased levels of parent stress [5]. Pelham and Lang found that ADHD was associated with increased parental alcohol use [20]. Befera and Barkley demonstrated that mothers of hyperactive children reported more depressive symptoms and marital discord compared to those of healthy children [31]. Given the aforementioned potential influences of ADHD, the present finding could be partly explained by the distress/protection QOL model, which suggests that QOL is the outcome of an interaction between various protective factors and a number of distressing factors [32]. QOL decreases if distressing factors (such as disturbances to family and marital functioning, disrupted parent–child relationships, increased parental alcohol use and depressive symptoms) predominate over protective factors (such as social support from family and friends, self-efficacy, task and avoidance). Although the poorer QOL experienced by this group of parents is expected, it is interesting that it is not so much the ADHD symptoms, but the presence of emotional and hyperactivity/inattention symptoms in the children that is significantly correlated with the parents’ QOL. In addition, it should be noted that 10.4% of the parents in the present study had a history of lifetime psychiatric disorders, which might contribute to their lower QOL, although on multiple analyses the history of lifetime psychiatric disorders was not independently associated with any QOL domain.

As well as factors relating to the children's ADHD symptoms, parents’ own characteristics expectedly also contribute to their QOL. Similar to previous findings [33, 34], parents with major medical conditions reported lower physical and social QOL domains. We found that higher educational level had a favourable effect on physical and psychological QOL domains in parents of children with ADHD, which was consistent with earlier findings in both the general population [35] and in subjects with chronic physical illnesses such as asthma and diabetes [36, 37]. The possible reasons might be that well-educated subjects can find appropriate employment and their living conditions could more likely satisfy their needs and expectations accordingly, and subjects with higher education have more access to information on ADHD or the illnesses they suffer, and are more aware of treatment strategies, so are less stressed. Therefore, in light of the Satisfaction QOL Model [38], they would have a higher QOL compared to subjects with lower levels of education.

Higher household monthly income was associated with better environmental QOL domain in this sample. Fitzgerald et al. suggested that subjects’ QOL was independent of their living standard as long as it reached a certain minimum level [12]. We suggest that the average living standard in the present sample did not reach the ‘certain minimum level’ although the household monthly income was comparable with the local average level (approximately HKD16 700) during the same period. In addition to monthly income, living standard was determined by many other factors such as housing conditions, price level etc., which were not measured in the present study. More variables relevant to living standard should be included in future studies.

We found that severity of emotional symptoms was associated with lower physical QOL domain. Contrary to our expectations, however, presence of comorbid pervasive developmental disorder was associated with higher physical and environmental QOL domains, and severity of hyperactivity/inattention symptoms of the children with ADHD was associated with higher social QOL level of the parents. We could offer no explanation for this striking finding. To date we are not aware of any data or evidence suggesting a positive association between any pervasive developmental disorder or hyperactivity/inattention symptoms in children and the QOL of their parents. Longitudinal studies may shed light on this unexpected and inexplicable connection. In the present study the SWAN hyperactivity/impulsivity score had also a mild positive relationship with social QOL, but did not reach a significant level (r = 0.20).

The present results should be interpreted with caution due to certain methodological limitations. First, the sample size was relatively small. Second, the study was cross-sectional, therefore the causality of the relationship between QOL and sociodemographic and clinical variables could not be explored. In order to clarify the causal relationship between QOL and other relevant factors, longitudinal studies involving more variables (such as parental functioning, parenting stress, marital quality etc.) and a larger sample are needed in the future. Third, without a control group, comparisons could be made only with the Hong Kong norms found using the WHOQOL-Bref [30]. A matched control group would have been more appropriate. Fourth, the majority of the parents involved were mothers (83.1%). Given the previous findings that there could be differences in maternal and paternal parenting practice [19], both fathers and mothers of children with ADHD should be interviewed in future studies. Finally, the present results indicated that of the six correlates of QOL, three are ADHD related (severity of emotional and hyperactivity/inattention symptoms and presence of comorbid pervasive developmental disorder) and three are parent related (presence of major medical conditions, educational level and household monthly income). Therefore we cannot exclude the possibility that the parents who had a lower QOL previously were likely to have it lowered further by parenting a child with ADHD. As a result, the potential interaction between ADHD- and parent-related factors should be clarified in future longitudinal studies with a large sample size.

In conclusion, parents of children with ADHD had a lower QOL in all the domains when compared with the norm of the general population in Hong Kong. Whether these results underline the deleterious effect of ADHD suffered by children on the QOL of the parents needs to be further investigated. Because of their significant correlations with different domains of QOL, more attention should be paid to children with co-occurring emotional symptoms. Attention should also be given to parents with major medical conditions, lower educational level and lower household monthly income. In order to improve QOL of parents having a child with ADHD, mental health professionals could adopt more specific measures based on the findings of the current study, such as reducing co-occurring emotional symptoms by optimizing treatment of ADHD.

Footnotes

Acknowledgements

The authors would like to sincerely thank Professor G. S. Ungvari in the Department of Psychiatry at the Chinese University of Hong Kong for his valuable comments in the preparation of this manuscript. We are also grateful to Dr Arthur Mak and other staff in the children's psychiatric clinic of Alice Ho Miu Ling Nethersole Hospital for their assistance in the project.

References

1. American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 4th edn. Washington, DC: American Psychiatric Association, 1994.

2. King

, Griffin

, Hodges

, A systematic review and economic model of the effectiveness and cost-effectiveness of methylphenidate, dexamfetamine and atomoxetine for the treatment of attention deficit hyperactivity disorder in children and adolescents. Health Technol Assess 2006; 10:iii–iv, xiii–146.

3. Taylor

Dopfner

Sergeant

. European clinical guidelines for hyperkinetic disorder: first upgrade. Eur Child Adolesc Psychiatry 2004; 13(Suppl 1)17–30.

4. Leung

Luk

Taylor

Mak

Bacon-Shone

. The diagnosis and prevalence of hyperactivity in Chinese schoolboys. Br J Psychiatry 1996; 168: 486–496.

5. Johnston

Mash

. Families of children with attention-deficit/hyperactivity disorder: review and recommendations for future research. Clin Child Fam Psychol Rev 2001; 4: 183–207.

6. Alessandri

. Attention, play, and social behavior in ADHD preschoolers. J Abnorm Child Psychol 1992; 20: 289–302.

7. DuPaul

McGoey

Eckert

VanBrakle

. Preschool children with attention-deficit/hyperactivity disorder: impairments in behavioral, social, and school functioning. J Am Acad Child Adolesc Psychiatry 2001; 40: 508–515.

8. Harpin

. The effect of ADHD on the life of an individual, their family, and community from preschool to adult life. Arch Dis Child 2005; 90(Suppl 1)2–7.

9. Hill

Schoener

. Age-dependent decline of attention deficit hyperactivity disorder. Am J Psychiatry 1996; 153: 1143–1146.

10.

10. Weiss

Murray

. Assessment and management of attention-deficit hyperactivity disorder in adults. CMAJ 2003; 168: 715–722.

11.

11. Collins

Hogan

Desai

. Measurement of therapeutic response in schizophrenia. A critical survey. Schizophr Res 1991; 5: 249–253.

12.

12. Fitzgerald

Williams

Corteling

. Subject and observer-rated quality of life in schizophrenia. Acta Psychiatr Scand 2001; 103: 387–392.

13.

13. Tischler

Karim

Rustall

Gregory

Vostanis

. A family support service for homeless children and parents: users’ perspectives and characteristics. Health Soc Care Community 2004; 12: 327–335.

14.

14. Phelan

Lee

Howe

Walter

. Parenting and mental illness: a pilot group programme for parents. Australas Psychiatry 2006; 14: 399–402.

15.

15. Mahoney

Jouriles

Scavone

. Marital adjustment, marital discord over childrearing, and child behavior problems: moderating effects of child age. J Clin Child Psychol 1997; 26: 415–423.

16.

16. Harrist

Alinslie

. Marital discord and child behavior problems. J Fam Issues 1998; 19: 140–163.

17.

17. Moss

Rousseau

Parent

St-Laurent

Saintonge

. Correlates of attachment at school age: maternal reported stress, mother-child interaction, and behavior problems. Child Dev 1998; 69: 1390–1405.

18.

18. Benzies

Harrison

Magill-Evans

. Parenting stress, marital quality, and child behavior problems at age 7 years. Public Health Nurs 2004; 21: 111–121.

19.

19. Ellis

, Nigg

. Parenting practices and attention-deficit/hyperactivity disorder: new findings suggest partial specificity of effects. J Am Acad Child Adolesc Psychiatry 2008; [Epub ahead of print.].

20.

20. Pelham

Jr Lang

. Can your children drive you to drink? Stress and parenting in adults interacting with children with ADHD. Alcohol Res Health 1999; 23: 292–298.

21.

21. Podolski

Nigg

. Parent stress and coping in relation to child ADHD severity and associated child disruptive behavior problems. J Clin Child Psychol 2001; 30: 503–513.

22.

22. Counts

Nigg

Stawicki

Rappley

von Eye

. Family adversity in DSM-IV ADHD combined and inattentive subtypes and associated disruptive behavior problems. J Am Acad Child Adolesc Psychiatry 2005; 44: 690–698.

23.

23. Sawyer

Whaites

Rey

Hazell

Graetz

Baghurst

. Health-related quality of life of children and adolescents with mental disorders. J Am Acad Child Adolesc Psychiatry 2002; 41: 530–537.

24.

24. Besag

. Childhood epilepsy in relation to mental handicap and behavioural disorders. J Child Psychol Psychiatry 2002; 43: 103–131.

25.

25. Cohen

. Statistical power analysis for the behavioral sciences2nd edn. Erlbaum, Hillsdale, NJ 1988.

26.

26. WHO. The World Health Organization Quality of Life assessment (WHOQOL): position paper from the World Health Organization. Soc Sci Med 1995; 41:1403–1409.

27.

27. Chan

Ungvari

Shek

Leung Dagger

. Hospital and community-based care for patients with chronic schizophrenia in Hong Kong: quality of life and its correlates. Soc Psychiatry Psychiatr Epidemiol 2003; 38: 196–203.

28.

28. Goodman

. The Strengths and Difficulties Questionnaire: a research note. J Child Psychol Psychiatry 1997; 38: 581–586.

29.

29. Swanson

(2005), Schuck

, Mann

, Categorical and dimensional definitions and evaluations of symptoms of ADHD: the SNAP and the SWAN Ratings Scales [Draft]. Irvine, CA: UCL Child Development Center, 2005. Available from URL: http://www.adhd.net/SNAP_SWAN.pdf .,.

30.

30. Leung

Tay

Cheng

Lin

. Hong Kong Chinese version World Health Organisation Quality of Life-Abbreviated version. Hong Kong Hospital Authority, Hong Kong 1997.

31.

31. Befera

Barkley

. Hyperactive normal girls and boys: mother–child interaction, parent psychiatric status and child psychotherapy. J Child Psychol Psychiatry 1985; 26: 439–452.

32.

32. Ritsner

, Modai

, Endicott

, Differences in quality of life domains and psychopathologic and psychosocial factors in psychiatric patients. J Clin Psychiatry 2000; 61:880–889; quiz 890.

33.

33. Balon

Aker

Crowther

. A comparison of active and simulated chiropractic manipulation as adjunctive treatment for childhood asthma. N Engl J Med 1998; 339: 1013–1020.

34.

34. Herridge

Cheung

Tansey

. One-year outcomes in survivors of the acute respiratory distress syndrome. N Engl J Med 2003; 348: 683–693.

35.

35. de Belvis

Avolio

Sicuro

. Social relationships and HRQL: a cross-sectional survey among older Italian adults. BMC Public Health 2008; 8: 348.

36.

36. Kalpaklioglu

Baccioglu

. Evaluation of quality of life: impact of allergic rhinitis on asthma. J Invest Allergol Clin Immunol 2008; 18: 168–173.

37.

37. Goz

Karaoz

Goz

Ekiz

Cetin

. Effects of the diabetic patients’ perceived social support on their quality-of-life. J Clin Nurs 2007; 16: 1353–1360.

38.

38. Lehman

Ward

Linn

. Chronic mental patients: the quality of life issue. Am J Psychiatry 1982; 139: 1271–1276.

Quality of Life in Parents of Children with Attention-Deficit–Hyperactivity Disorder in Hong Kong