Long-Term Tolerability and Safety of Pharmacological Treatment of Adult Attention-Deficit/Hyperactivity Disorder: A 6-Year Prospective Naturalistic Study.

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a behavioral disorder typically treated with stimulants and atomoxetine. Data on long-term tolerability and safety of such pharmacological treatment in subjects diagnosed in adulthood are limited.

METHODS

A cohort of adults diagnosed with ADHD according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria was followed-up on an average of 6 years after first evaluation. Of 168 adults, 112 (67%) who initiated medication were available for follow-up. Data were obtained from patient record data, self-report forms, and a telephone interview.

RESULTS

Of the 112 participants assessed, 57 (51%) were still on treatment with methylphenidate (MPH) at follow-up and 55 (49%) had discontinued. The 3 leading reasons for discontinuing treatment with MPH were lack of effect (29%), elevated mood or hypomania (11%), and losing contact with the prescribing physician (9%). The most common adverse effects in subjects still on treatment with MPH were decreased appetite (28%), dry mouth (24%), anxiousness/restlessness and increased pulse frequency (19% each), decreased sexual desire (17%), and perspiration (15%). Subjects still on treatment reported increased quality of life, a higher level of functioning, and a greater understanding of their way of functioning from those being close compared with nonmedicated subjects.

CONCLUSIONS

The high attrition rate underscores the need for further research to identify possible modes to increase retention to treatment. Those diagnosed with ADHD and on long-term treatment with stimulants experience mild and tolerable adverse effects.