ADHD was more common among participants with methamphetamine use disorders and was independently associated with everyday functional difficulties. That finding makes developmental history relevant; it does not establish that methamphetamine caused ADHD or that every reported difficulty came from drug exposure.
Obermeit and colleagues studied 400 participants with methamphetamine use disorders within 18 months of evaluation and 355 comparison participants. A structured clinical interview assessed ADHD, alongside neuropsychiatric testing and self-reported everyday functioning. Approximately 21% of methamphetamine participants and 6% of comparisons had lifetime ADHD diagnoses.
Combined and hyperactive subtypes were more prevalent in the methamphetamine group; the inattentive subtype did not show the same significant group pattern. Persistence of childhood combined-type ADHD into adulthood also differed. Within methamphetamine participants, lifetime ADHD was independently associated with cognitive symptoms, dependence in instrumental daily activities and unemployment after adjustment for specified covariates. These were measured associations, not proof of a single causal pathway.
ADHD diagnosis and a history of methamphetamine use concern different information. Neither constitutes a contemporaneous blood or oral-fluid concentration, and this study did not establish a chemical cutoff for functional impairment. Retrospective developmental histories and self-reported function have limitations, while adjustment cannot eliminate all confounding. The cross-sectional analysis does not determine whether ADHD increased vulnerability to use, use altered symptoms, or shared factors contributed to both. In a forensic assessment, investigate symptom onset, prior educational records, treatment and current function. The study supports considering competing and coexisting explanations; it does not authorize diagnosing a particular person from population percentages or attributing all difficulties to one disorder.
For a separate example of the limits of use-history comparisons, see our current-user driving study. The design and measured outcome determine which conclusions can be carried into an individual case.
Original investigation: doi:10.1016/j.addbeh.2013.08.010.