Adult ADHD: Prevalence, Identification, Treatment

Although once considered a childhood disorder that would remit in adolescence, we now know that there is a 70% persistence of attention deficit hyperactivity disorder (ADHD) into adulthood [Barkley RA et al. J Abnormal Psychiatry 2002]. Gabriel Kaplan, MD, Hoboken University Medical Center, Hoboken, NJ, provided guidance on how to identify and treat adult ADHD.

Some of the most comprehensive data on adult ADHD came from the results of the National Comorbidity Survey Replication (NCS-R) [Kessler RC et al. Am J Psychiatry 2006], a nationally representative household survey that used a lay-administered diagnostic interview to assess a wide range of DSM-IV disorders. The NCS-R included a screen for adult ADHD in a probability subsample of 3199 subjects aged 18 to 44 years. A subset of 154 subjects also completed structured interviews (ie, the Adult DHD Clinical Diagnostic Scale v1.2, based on ADHD-DSM-IV strict criteria and the WHO-Composite International Diagnostic Interview). The results of this study showed an estimated prevalence of current adult ADHD of 4.4%. There was a high level of comorbidity (mood disorder 38.3%, anxiety disorder 47.1%, substance abuse 15.2%) and significantly elevated odds of disability in all dimensions of basic and instrumental functioning, as assessed by the WHO Disability Assessment. Only 10.9% of the respondents had received ADHD treatment in the previous 12 months. Other studies have shown a similar pattern of impairment [Murphy K & Barkley RA. Compr Psychiatry 1996; Biederman J et al. J Clin Psychiatry 2006; Barkley RA et al. ADHD in Adults: What the Science Says. New York, NY: Guilford Press. 2008].

A diagnosis of ADHD can be complicated by the presence of psychiatric and medical conditions that are known to mimic ADHD [Searight HR et al. Am Fam Physician 2000; Stern MA. CNS Spectr 2008 13(Suppl 15)]. It is also important to note that the pattern of ADHD symptoms changes over time. While hyperactivity, impulsivity, and inattention are the cardinal symptoms of ADHD, over time adult patients present with less overt hyperactivity and impulsivity, although inattention remains the most persistent aspect of the ADHD triad [Biederman et al. Am J Psychiatry 2000; Adler L, Cohen J. Psychiatr Clin North Am 2004] (Table 1).

When conducting a diagnostic workup for ADHD, Dr. Kaplan recommends a comprehensive psychiatric interview with expanded focus on:

• Present illness–academic and work status, areas of impairment, and the presence of significant symptoms of substance abuse, or affective or anxiety disorder

• Past History–the presence of ADHD childhood symptoms (corroborated with relatives when possible)

• Medical History–current medications, history of head trauma or other neurological conditions, presence of endocrinology problems

Appropriate rating scales include the Conners' Adult ADHD Rating Scale (CAARS), the Brown ADD Rating Scale (BAADS), and the Adult ADHD Self Report Scale v1.1 (ASRS-v1.1) for current symptoms and the Wender Utah Rating Scale (WURS) for retrospective childhood symptoms [Brown T ed. Comorbidities Handbook for ADHD Complications in Children and Adults. Washington DC, American Psychiatric Press. 2009]. It is expected that the criteria for ADHD will be revised to be more appropriate for the adult population in DSM-V.

The mainstay of treatment for ADHD is either long- or short-acting stimulants. There are currently 6 medications that are approved (5 stimulants; 1 nonstimulant). Adjunctive psychotherapy can also be associated with improved outcomes.