Abstract
Introduction
ADHD is a common neurodevelopmental disorder with a worldwide prevalence of 3.4% in children and adolescents (Polanczyk, Salum, Sugaya, Caye, & Rohde, 2015). Its core symptoms, inattention and hyperactivity-impulsivity, and associated impairments can be markedly reduced by evidence-based treatments (Faraone et al., 2015). Several studies have proven long-term consequences of ADHD including higher comorbidity in later life (Meinzer et al., 2016; Tandon, Tillman, Agrawal, & Luby, 2016). Hechtman et al. (2016) concluded that a successful treatment of ADHD symptoms might be protective against anxiety, depression, and substance use disorder.
Whereas the evidence for pharmacological treatment on ADHD symptom reduction is high, evidence for non-pharmacological interventions is controversially discussed (D. Daley et al., 2014; Sonuga-Barke et al., 2013). So far, the largest trial regarding the effectiveness of interventions was the multimodal treatment study of children with ADHD (MTA). This study showed that medication management was superior to only behavioral treatment (The MTA Cooperative Group, 1999). The findings further indicated that the combination of both treatments—compared with pharmacological treatment only—had benefits regarding non-ADHD symptoms, levels of functioning, and the need for lower drug doses (The MTA Cooperative Group, 1999; Vitiello et al., 2001).
The MTA long-term follow-up showed that the percentages of those with adequate medication declined by more than a quarter within less than 1 year after the randomized controlled trial phase (Swanson et al., 2017). Conversely, in the group originally assigned to receiving only behavioral treatment, the proportion of those taking ADHD medication substantially increased from 14% to 31% in the same time period (Swanson et al., 2017). Most population-based studies on ADHD treatments only focused on medication and/or included prevalent patients but did not show treatment trajectories or the mix of interventions in routine clinical practice. It is not well studied whether in routine care, pharmacological and/or non-pharmacological interventions are initiated in children after a first diagnosis of ADHD. In addition, factors influencing the decision as to which interventions are provided in the course of the disorder are understudied. Physicians’ professional training (Kovshoff et al., 2012) and patients’ characteristics (Sonuga-Barke, 2016) are suggested factors. Information on the treatment of children with ADHD in clinical routine from a longitudinal perspective is of high importance to also interpret prescription analyses, guideline adherence, and characteristics of health care systems.
Based on German claims data, this study aimed to (a) show the proportion of individuals with medication and/or psychotherapy over a 5-year follow-up among treatment-naïve children with incident ADHD in routine care and (b) find characteristics—at the first diagnosis—that are associated with the received treatments until end of follow-up. Importantly, both ADHD drugs and psychotherapy are fully reimbursed for underage children by the health insurance providers in Germany. Hence, the study population had equal access to both treatment options.
Method
Data Source
This study was based on claims data from two nationwide statutory health insurance (SHI) providers included in the German Pharmacoepidemiological Research Database (GePaRD) (Pigeot & Ahrens, 2008). In addition to demographic data, the database contains information on dispensed drug prescriptions, outpatient and inpatient services, and diagnoses. Drugs are identifiable through the anatomical–therapeutic–chemical (ATC) code. Diagnoses are coded according to the German modification of the International Classification of Diseases and Related Health Problems, 10th Revision (ICD-10-GM). Outpatient services are recorded as billing codes included in the doctor’s fee schedule.
Study Design
We conducted a cohort study and included children aged 5 to 12 years in 2010 and with a continuous insurance period from January 1, 2009, to December 31, 2015. Of these, children with an incident ADHD diagnosis (ICD-10-GM F90 and F98.8) in 2010 were identified using the following algorithm: children had to have either (a) one inpatient diagnosis, (b) at least two outpatient diagnoses, or (c) both, an outpatient diagnosis and a dispensation of an ADHD drug (codes see below). Cohort entry was defined as the date of the first ADHD diagnosis in 2010. Excluded were children with an ADHD diagnosis in 2009 and those who had psychotherapy before the ADHD diagnosis. Cohort exit was defined as the date 5 years after cohort entry.
Outcomes
Outcomes were defined as mutually exclusive treatment groups such as receiving treatment with ADHD medication and/or psychotherapy after cohort entry. Use of medication was identified based on the first ADHD drug dispensation. ADHD drugs comprised methylphenidate (ATC-code N06BA04), atomoxetine (N06BA09), lisdexamfetamine (N06BA12), and dexamfetamine (N06BA02). Psychotherapy was identified based on the first billing code. Included were trial sessions (code 35150), which can be considered the very first visits to a therapist, as well as psychotherapeutic sessions that were approved by the patient’s insurance company (codes 35200–35225).
Characteristics Potentially Associated With the Received Treatment
The specialty of the diagnosing physician was based on information in the quarter of cohort entry. In GePaRD, information on the physician’s specialty is only available in an outpatient setting, so that children diagnosed in an inpatient setting were assigned to a separate category. The category “psychotherapist” was aggregated using the following specialties: (child and adolescent) psychotherapists, medical psychotherapists, and specialists for psychosomatic medicine and psychotherapy. In contrast to psychotherapists, medical psychotherapists and specialists for psychosomatic medicine and psychotherapy are allowed to prescribe medication (Institute for Quality and Efficiency in Health Care [IQWiG], 2016). However, as all three specialties are typically offering non-pharmacological treatment like psychotherapy, we grouped them into one category. The type of ADHD diagnosis was distinguished between with (ICD-10-GM F90) and without (ICD-10-GM F98.8) hyperactivity based on the recorded ADHD diagnosis at cohort entry. Psychiatric comorbidities were selected a priori based on suggestions from a clinical expert. They were queried in the cohort entry quarter and the preceding four quarters. Outpatient diagnoses coded as confirmed and inpatient discharge diagnoses were used. Psychiatric hospitalizations were defined using main discharge or secondary psychiatric diagnoses (ICD-10-GM F00-F99) in the 1-year baseline before and excluding cohort entry.
Ethical Considerations
The use of SHI data for scientific research is regulated by the Code of Social Law (SGB X) in Germany. All involved SHIs and the competent authorities approved the use of the data for this study; no ethical approval was necessary. Informed consent of the involved insurants was not required by law.
Analyses
To identify statistical differences regarding the characteristics at first ADHD diagnosis between treatment groups, Pearson’s χ2 test at a 5% α level was used. Multinomial logistic regression was used to obtain odds ratios and corresponding 95% confidence intervals for the association between characteristics at the first ADHD diagnosis and the chosen treatment approach comparing children with “medication” and “only psychotherapy” with those with no treatment. In a logistic regression model, children with “medication and psychotherapy” were compared with those with “only medication” among those who ever received medication. Sex, age, and the specialty of the diagnosing physician were always included as independent variables. The other characteristics were only included if their frequency differed statistically significant between the treatment groups. All statistical analyses were conducted using SAS version 9.3.
Results
The study cohort comprised 12,250 treatment-naïve children aged 5 to 12 years with a first diagnosis of ADHD (Figure 1). The prevalence for ADHD according to the algorithm was 5.3% (38,706 / 724,934).
Flow diagram.
Period Prevalence of Treatments
Within the first year after the first ADHD diagnosis, almost 25% of the cohort received medication and about 6% received only psychotherapy (Table 1). At the end of follow-up, more than one third was ever pharmacologically treated and more than one in 10 was treated with psychotherapy only. About 27% of those with medication additionally had psychotherapy during the observation period. Added up in both groups—“medication” and “only psychotherapy”—21% (n = 2,572) of the cohort members ever received psychotherapy. Of these, 59% ever had psychotherapeutic sessions which required an approval from the SHI. Among all patients who ever received psychotherapy, a diagnostic code of ADHD (particularly F90) was most frequently recorded by the treating therapist at their first psychotherapeutic session, followed by emotional disorders with onset specific to childhood (F93). This also applied for cohort members who received only psychotherapy.
Period Prevalence of Medication and Psychotherapy Among Treatment-Naïve Children After First ADHD Diagnosis Over 5 Years.
Note. Treatment categories are mutually exclusive except “medication and psychotherapy,” which is a subgroup of “medication.” n = sample size.
Includes methylphenidate, atomoxetine, lisdexamfetamine, and/or dexamfetamine.
Including trial sessions.
Characteristics at First ADHD Diagnosis
Stratified by the treatment received within 5 years, the characteristics of cohort members at cohort entry differed regarding sex, age groups, specialty of the diagnosing physician, type of ADHD diagnosis, and most of the a priori selected comorbidities (Table 2). The overall percentage of cohort members with an ADHD diagnosis without hyperactivity was 22%. This proportion was substantially lower in those with medication during follow-up (6.5%) and similar in those who received only psychotherapy (27%). The most frequent psychiatric comorbidities in all cohort members were, in decreasing order of frequency, specific developmental disorders (47.9%), conduct disorders (18.0%), emotional disorders with onset specific to childhood (11.1%), and any depression (8.0%).
Characteristics at First ADHD Diagnosis by Treatment Ever Received Within 5 Years From the First ADHD Diagnosis.
Note. n = sample size; ICD-10 = International Classification of Diseases and Related Health Problems, 10th Revision.
The group “medication” included individuals with additional psychotherapy (27%); it was further stratified for the comparison “medication and psychotherapy” versus “only medication” in Table 4.
One child could have more than one comorbidity.
Defined as inpatient treatment with a main or secondary psychiatric diagnosis (ICD-10 F00-F99) in the 1 year baseline before and excluding cohort entry.
Factors Associated With Receiving Medication Compared With Receiving No Treatment
Male sex and older age at the first ADHD diagnosis were associated with receiving medication within 5 years (Table 3). Children diagnosed by non-specialists (pediatricians and general practitioners) were less likely to be treated with medication as compared with those diagnosed by a child and adolescent psychiatrist. Having an ADHD diagnosis “with hyperactivity” increased the odds of receiving medication more than fivefold as compared to “without hyperactivity.” Children with the following comorbidities at the first ADHD diagnosis were more likely to be prescribed medication within 5 years: depression, specific developmental disorders, and conduct disorders.
Adjusted Odds Ratios for Characteristics at the First ADHD Diagnosis Associated With the Received Treatment Within 5 Years.
Note. CI = confidence interval; n = sample size.
The multinomial logistic regression model is adjusted for all variables in this table.
Children who received neither ADHD medication nor psychotherapy served as the reference group (n = 6,411).
p < .05.
Factors Associated With Receiving Only Psychotherapy Compared to Receiving No Treatment
Boys were more likely to receive only psychotherapy within 5 years from the first ADHD diagnosis (Table 3). Compared to being diagnosed by a child and adolescent psychiatrist, children who were diagnosed by a pediatrician were less likely and those diagnosed by a psychotherapist were substantially more likely to receive only psychotherapy. Children with the following comorbidities at the first ADHD diagnosis were more likely to receive only psychotherapy within 5 years: neurotic and somatoform disorders, conduct disorders, and emotional disorders with onset specific to childhood.
Factors Associated With Receiving Medication and Psychotherapy Compared With Receiving Medication Only
Compared with children aged 5 to 6 years, children aged 10 to 12 years at the first diagnosis were less likely to additionally receive psychotherapy (Table 4). Being initially diagnosed by a non-specialist and by a psychotherapist increased the odds of receiving medication and psychotherapy as compared with being diagnosed by a child and adolescent psychiatrist. In the group of patients with both treatments, 25% were initially diagnosed by a child and adolescent psychiatrist (30% of those with medication only). Children with the following comorbidities at the first ADHD diagnosis were more likely to receive both medication and psychotherapy within 5 years: depression, neurotic and somatoform disorders, conduct disorders, and emotional disorders with onset specific to childhood. Being diagnosed with mental retardation at cohort entry lowered the odds of receiving psychotherapy in addition to medication by 52%.
Comparison of Those With Versus Without Psychotherapy Among Children With ADHD Diagnosis Who Received Medication.
Note. CI = confidence interval; n = sample size; NA = not applicable as these variables were not included in the respective model.
The model is adjusted for all variables in this table (except “NA”).
One child could have more than one comorbidity.
p < .05.
Discussion
In this study, we investigated the initiation of pharmacological and psychotherapeutic treatments among children newly diagnosed with ADHD by using health insurance data. Moreover, we identified characteristics recorded at the first ADHD diagnosis that were associated with the received treatments. It is particularly noteworthy that—due to equal access to both treatment options—the population in this study was truly free to choose between medication and/or psychotherapy. Use of medication started early from the initial ADHD diagnosis and few patients started with psychotherapy. After 5 years from the first ADHD diagnosis, a substantial proportion of children received only psychotherapy and relatively few received both, medication and psychotherapy.
Medication Versus No Treatment
Our results indicated that the diagnosing person’s specialty had an influence on prescribing ADHD medication, as suggested by Kovshoff et al. (2012). Children who were initially diagnosed by a non-specialist, that is, pediatricians and general practitioners, were less likely to receive medication. It is possible that being diagnosed by a non-specialist hampered access to potentially needed interventions at least in some cases, or that at the patients’ place of residence, specialists were simply lacking. It is generally recommended that treatment with medication such as methylphenidate must at least be under the supervision of a specialist (Committee for Medicinal Products for Human Use, 2009). In this study, we did not know whether non-specialists referred the child to a specialist to confirm the ADHD diagnosis and/or to check the need for interventions.
More severe ADHD cases, as indicated by the type of diagnosis “with hyperactivity” in our study, were far more likely to receive medication. Our results therefore confirmed the assumption made by Sonuga-Barke (2016) that patients with more severe presentations are particularly more likely to be prescribed medication. Furthermore, children with certain comorbid psychiatric disorders—considered as a proxy for a more complex presentation of ADHD—were more likely to receive medication, which was also assumed by Sonuga-Barke (2016). Especially comorbid conduct disorders—representing externalizing symptoms—showed the strongest association by increasing the odds to receive medication by 35%. This indicates that the severity of ADHD symptoms and comorbidities are part of the decision to initiate medication, which is in line with recommendations from ADHD guidelines.
Only Psychotherapy Versus No Treatment
The relatively high proportion of patients who received only psychotherapy was surprising; there were even more children with a diagnosis of ADHD who received only psychotherapy rather than medication and psychotherapy. ADHD symptoms might not have been the most impairing factors in these cases. In fact, comorbid psychiatric disorders that were associated with receiving only psychotherapy—namely, neurotic and somatoform disorders (including anxiety and obsessive-compulsive disorder), conduct disorders (including oppositional defiant disorders), and emotional disorders with onset specific to childhood (also including anxiety)—are accompanied by impairing internalizing and externalizing symptoms for which psychotherapeutic interventions have sound evidence (D. Daley et al., 2014; Seidman, 2014). However, the frequencies of these comorbidities in our study did not explain the therapeutic approach with only psychotherapy in all of the cases. Notably, although depressive disorders are typical indications for psychotherapy, comorbid depression was not associated with receiving only psychotherapy. In addition, although 4 times more patients with only psychotherapy compared with those receiving medication were classified as ADHD “without hyperactivity,” still about three quarters of those receiving only psychotherapy had ADHD “with hyperactivity.” More importantly, ADHD was the most frequent reason for the first psychotherapeutic visit of these patients, as measured by the recorded diagnoses of the treating therapist. In fact, the most frequent diagnostic code was “hyperkinetic disorder” (F90), which is considered to be an even narrower and more severe subtype of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) “attention-deficit/hyperactivity disorder” (Bachmann, Wijlaars, et al., 2017). Being diagnosed by a psychotherapist was strongly associated with receiving only psychotherapy. As this non-pharmacological treatment is the typical—for non-medical psychotherapists the only available—therapeutic method of these therapists, higher odds for receiving only psychotherapy were expected. It is unknown whether attending these specialists was initiated by the parents or a potentially referring physician.
Our results suggest that ADHD symptoms were in some cases treated with psychotherapy only, although blinded evidence for the efficacy of psychotherapy on ADHD symptoms is lacking (D. Daley et al., 2014; Sonuga-Barke et al., 2013). However, the decision on the type of intervention may depend on several further factors this study could not measure such as treatment perceptions by patients, parents, health professionals, and teachers (Bussing et al., 2012). In addition, comorbid disorders may have developed at some point after the initial diagnosis. Whether the psychotherapy only group was sufficiently treated remains unsolved in our study. It should be noted that treatment of ADHD with only psychotherapy may be in line with ADHD guidelines in cases where families decide against medication. However, medication should be advised if psychological treatment did not lead to substantial improvement within a few weeks (Taylor et al., 2004).
Medication and Psychotherapy Versus Only Medication
In our study, less than three in 10 pharmacologically treated patients received additional psychotherapy. Low proportions of psychotherapy among children treated with ADHD medication were also found based on U.S. claims data (Gellad et al., 2014). The authors assumed that apart from the availability of psychotherapeutic treatment—which also applies to our study—parents’ or physicians’ preferences for non-pharmacological care might influence receipt of psychotherapy as well (Gellad et al., 2014). In our study, the odds of receiving both treatments were in fact higher when non-specialists or psychotherapists diagnosed ADHD first as compared with being diagnosed first by a child and adolescent psychiatrist. The lower odds of receiving combined therapy for patients initially diagnosed by child and adolescent psychiatrists in our study seem astonishing. Possible reasons may include that in Germany, there is a unique model of outpatient social-psychiatric practices to improve community care. These are often run by child and adolescent psychiatrists. Psychotherapeutic treatments in these practices are not recorded through billing codes as used in this study, leading to an underestimation of the frequency of psychotherapy.
Notably, patients with psychiatric comorbidities which represent internalizing—such as depression and anxiety—as well as externalizing symptoms (conduct disorders) were more likely to receive psychotherapy in addition to medication. The lower odds of receiving additional psychotherapy when mental retardation was present may reflect the fact that the effectiveness of psychotherapy for this disorder is yet to be empirically confirmed (Lynch, 2004). An additional explanation may be the low proportion of psychotherapists who deal with the population of children with low IQs. Medication-only treatment for school-aged children with severe ADHD (i.e., “hyperkinetic disorder”) as in our study is in line with ADHD guidelines (National Institute for Health and Care Excellence, 2016; Subcommittee on Attention-Deficit/Hyperactivity Disorder, Steering Committee on Quality Improvement, 2011; Taylor et al., 2004). However, given that psychological treatment plays an important role in guideline recommendations, our results suggest that adherence to ADHD guidelines regarding treatment with psychotherapy is suboptimal.
Strengths and Limitations
A major strength of our study is the use of claims data as they represent routine care in a large population, and recall bias can be ruled out. Furthermore, due to the applied algorithm to identify children with incident ADHD, potential case misclassification was minimized as recommended by M. F. Daley et al. (2017). Another strength is that ADHD medication was identified based on dispensations in pharmacies and not on the fact whether a prescription was issued by a physician. Furthermore, the billing codes used to identify psychotherapy are highly specific. In Germany, the SHIs need to approve psychotherapy for each patient—in cases with more than a few trial sessions—based on an evaluation before costs are covered. For this, the therapist must justify the need for psychotherapy. The application for psychotherapy also includes a doctor’s report. Only if the evaluator—with special training—approves the application, the SHI will cover the costs (IQWiG, 2016).
Our study also has some limitations. First, it is unknown whether dispensed medication was taken by the patients. Second, the high specificity regarding the identification of psychotherapy in our study might underestimate the actual prevalence. However, the study covered all codes used by psychotherapists. In addition, we did not directly assess parent-training/education programs, but these programs are substantial parts of psychotherapy in clinical practice in Germany. Fourth, test results on diagnostic instruments were lacking and we classified the type of ADHD diagnosis based on the recorded ICD-10 codes F90 or F98.8 as ADHD with or without hyperactivity, respectively. Although F98.8 is a rather unspecific code, we considered it a valid ADHD-identifying measure as used in other studies (Bachmann, Philipsen, & Hoffmann, 2017; Dalsgaard, Østergaard, Leckman, Mortensen, & Pedersen, 2015) due to the following reasons: (a) the estimated prevalence for ADHD as defined in our study is as expected according to DSM criteria based on a field study in a representative sample in Germany (Döpfner et al., 2008) and (b) the proportion of all ADHD cases who were classified as “without hyperactivity” (22%) was similar to results from a general community-based study (28%) with children in a similar age range based on diagnostic interviews (Counts, Nigg, Stawicki, Rappley, & von Eye, 2005) as well as to results from Germany (17%) based on clinical records from treating physicians (Setyawan et al., 2018). Fifth, although we tried to minimize case misclassification as described above, the severity of ADHD symptoms of the participants with an ADHD diagnosis in our cohort may vary. The group who received no treatment may include children with very mild ADHD symptoms. Therefore, there may be a selection bias for this group. Nevertheless, all children included in the cohort had received the ADHD diagnosis by their physician/psychotherapist. As the diagnosis potentially leads to substantial stigmatization (Lebowitz, 2016), it requires sound consideration. Furthermore, as we aimed to illustrate the actual situation in routine care, we deemed it important to include all children with an ADHD diagnosis—even those with very mild symptoms. Thus, we were able to interpret guideline adherence, for example, by showing that patients with more severe/complex presentations were more likely to receive treatment.
Conclusion
This study identified characteristics predicting whether a child newly diagnosed with ADHD—and with free access to medication and psychotherapy—receives pharmacological and/or psychotherapeutic treatment in routine care. In the German health system, patients with externalizing symptoms were more prone to receive any of the studied treatments than the average child diagnosed with ADHD. Comorbid internalizing symptoms were predictors for psychotherapy—both as monotherapy and in addition to medication. A first diagnosis with ADHD by a specialist and a more severe ADHD presentation were predictors for drug treatment. Our results indicate that treatment initiation is in line with recommendations from ADHD guidelines. However, treatment with psychotherapy appears to be suboptimal.
Future research is needed to address the questions raised by this study, for example, (a) what are the characteristics of longitudinal treatment trajectories, (b) why and how do parents decide to visit a certain physician or psychotherapist, (c) which recommendations are given by the diagnosing person, and (d) did children who received only psychotherapy see a child and adolescent psychiatrist with expertise in the diagnosis and treatment of ADHD?
Footnotes
Acknowledgements
The authors would like to thank all statutory health insurance providers which provided data for this study, namely, the DAK-Gesundheit and Die Techniker (TK). The authors would also like to thank Dr. Heike Gerds for proofreading the final manuscript.
Declaration of Conflicting Interests
The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: O.R. has received unrestricted educational grants from Bayer AG outside the submitted work; O.S., B.K., E.E.Ö., and O.R. are working at the Leibniz Institute for Prevention Research and Epidemiology – BIPS. Unrelated to this study, BIPS occasionally conducts studies financed by the pharmaceutical industry. Almost exclusively, these are post-authorization safety studies (PASS) requested by health authorities. The studies and the resulting publications are not influenced by the pharmaceutical industry. J.M.F. and M.K. have declared that they have no competing or potential conflicts of interest to declare.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was supported by the German Federal Ministry of Health with a grant for the “Aktion Psychisch Kranke e.V.” The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
