Diagnosing ADHD during active substance use: Feasible or flawed?

Background: Attention Deficit Hyperactivity Disorder (ADHD) is highly prevalent in patients with a substance use disorder (SUD). Because of possible problems with validity, diagnostic assessment of ADHD is usually postponed until after a period of abstinence, which may jeopardize adequate and timely treatment. The aim of this study is to investigate how a diagnostic assessment of ADHD in patients who are actively using substances compares to the results of a second assessment after a period of full or partial abstinence.

Methods: Prospective test-retest study in a SUD treatment center among 127 treatment seeking adult SUD patients with a comorbid diagnosis of adult ADHD. Conners' Adult ADHD Diagnostic Interview for DSM-IV was administered at intake and after four SUD treatment sessions.

Results: The mean time interval between intake and retest assessment was 78 days (SD = 32; range 31-248). At the second ADHD assessment, substance use had decreased to about 50% of baseline consumption. Of the 127 patients with an initial diagnosis of ADHD, 121 patients (95.3%) still fulfilled DSM-IV adult ADHD criteria at re diagnosis. Subtyping of ADHD was less stable (Cohen's Kappa = 0.53). Agreement on the number of childhood and adult ADHD symptoms between both assessments was good (intraclass correlation coefficient of 0.69 and 0.65, respectively). Sensitivity analyses in subgroups of patients who were fully abstinent during the second assessment yielded very similar results.

Conclusions: These findings strongly suggest that a pragmatic approach, in which patients are evaluated for ADHD even when they are not (yet) abstinent, is feasible and justifiable.