The Diagnostic and Statistical Manual of Mental Disorders – 5th edition (DSM-5™) states that the symptoms of ADHD are the same for adults and children; however, clinical observations highlight that adults have more diverse deficits in higher-level executive functioning and emotional control than children. The current study analysed the structure of an expanded set of adult ADHD symptoms in three pooled US samples:* a national household sample (n=108), a sample of health plan members (n=161) and a sample of adults referred for evaluation at an adult ADHD clinic (n=191).
This study was sponsored by Shire Pharmaceuticals
Samples were assessed for adult ADHD using version 1.2 of the Adult Clinician ADHD Diagnostic Scale (ACDS), a semi-structured research diagnostic interview tool utilised in clinical studies of adults with ADHD. The interview consisted of a retrospective assessment of childhood ADHD symptoms and an expanded set of more recent (past 6 months) symptoms, including nine DSM-5™ Criterion A1 (inattention deficit; AD) symptoms, eight Criterion A2 (hyperactivity/impulsivity deficit; HD) symptoms, and 14 non-DSM symptoms relevant to adult ADHD, including deficits in higher-level executive function and emotional control.
Exploratory factor analysis found four factors representing executive dysfunction/inattention,† hyperactivity, impulsivity and emotional dyscontrol. Empirically derived multivariate symptom profiles were broadly consistent with DSM-5™ inattentive-only, hyperactive/impulsive-only and combined presentation. Inattention including executive dysfunction/inattention and hyperactivity‑only were limited to hyperactivity without impulsivity.
Three important limitations exist within the study data. Compared with more recent studies, results from the ACDS assessment of emotional dyscontrol were less differentiated, and performance-based measures of neurocognitive functioning were not assessed. Furthermore, comorbid psychiatric disorders were not uniformly assessed across samples, making it impossible to determine whether the results obtained were specific to adults with ADHD.
Results from this study support the principle of executive dysfunction and emotional dyscontrol in adults with ADHD; showing that executive dysfunction is as central as DSM-5™ symptoms to adult ADHD, while emotional dyscontrol is more distinct but nonetheless part of the combined presentation of adult ADHD.
Read more about the structure of adult ADHD here
*The three pooled US samples consisted of the following: the NYU Langone sample, consisting of participants seeking treatment on the adult ADHD programme; the national general population sample, which was based on the National Comorbidity Survey Replication, and used to validate the ADHD Self-Report Scale (ASRS) screening scale for adult ADHD; and the health plan sample, consisting of participants belonging to a named healthcare plan which includes ASRS screening
†Including, but not limited to, all DSM-5™ inattentive symptoms. Moreover, non-DSM symptoms displayed factor loadings comparable with those of DSM symptoms
Adler LA, Faraone SV, Spencer TJ, et al. The structure of adult ADHD. Int J Methods Psychiatr Res 2017; Epub ahead of print.