Examining why patients with attention-deficit/hyperactivity disorder lack adherence to medication over the long term:...

To investigate the reasons why patients with attention-deficit/hyperactivity disorder (ADHD) adhere poorly to medications over the long term (≥ 1 year).

PubMed was reviewed for studies between 1997 and January 2015 citing the reasons for medication nonadherence using these main keywords: ADHD, amphetamine, methylphenidate, atomoxetine, guanfacine, clonidine, long term, and adverse effects. Non-English language articles were excluded as were those that had a follow-up of < 1 year.

Of 1,137 entries, 41 published articles citing reasons for subject withdrawal from treatment were included. None were included for clonidine.

Similar reasons for drug or study withdrawal were grouped together for analysis using a normalized numerical average, while unique reasons were analyzed individually.

Reasons for discontinuing Food and Drug Administration (FDA)-approved medication after 1 year included "own wish/remission/don't need" (19.9%; 95% CI, 9.0-30.80), "withdrew consent" (16.2%; 95% CI, 10.0-22.5), "adverse effects" (15.1%; 95% CI, 10.4-19.8) and "suboptimal effect" (14.6%; 95% CI, 8.5-20.6), with the most common adverse event being "reduction in weight/appetite" (19.2%; 95% CI, 5.1-33.4). Other important factors included age, long- versus short-acting medication, psychosocial stressors, and "stop feeling like him/herself" on medication.

The reasons why patients do not adhere to stimulant medication remain poorly studied and understood, especially over the long term. Standardizing the way studies evaluate patients who stop treatment and including more qualitative measures should lead to better treatment outcome and adherence to medication over the long term.