Objective: To review the literature on the prevalence, potential causes, and consequences of medication nonadherence in adult attention-deficit/hyperactivity disorder (ADHD).
Background: Attention-deficit/hyperactivity disorder is a common, chronic, and impairing neuropsychiatric disorder, affecting 4.4% of the US adult population. Medications alleviate many aspects of the disorder, but associated difficulties with disorganization and planning can lead patients to have poor adherence and subsequent treatment failure. This review will examine the scope and consequences of medication nonadherence in children and adults with ADHD.
Methods: Comprehensive literature reviews via PubMed searches were conducted for continuity of medication and medication adherence (and related terms) in ADHD (and ADD). The studies were reviewed and classified regarding prevalence, measure of adherence or continuity, etiology, and consequences of medication nonadherence in childhood/adolescent and adult ADHD.
Results: Studies of pharmacy claims databases and treatment studies have shown that the prevalence of medication discontinuation or nonadherence is between 13.2% to 64%. More studies have focused on medication adherence in children/adolescents than in adult ADHD. Medication nonadherence is more prevalent in immediate-release versus extended-release psychostimulants in childhood/adolescent ADHD, but differences in the formulations have not been studied extensively in adults. Current studies have almost exclusively relied on patient reports. Possible etiologies of medication nonadherence have not been examined with formal rating instruments in adult ADHD. The long-term consequences of medication nonadherence, in terms of impairments, have not been examined.
Conclusions: Studies have documented that medication nonadherence is common in childhood/adolescent ADHD. Further prospective studies are necessary to document the scope of the problem in adult ADHD and to examine the potential benefits of utilizing extended-release medications in adult ADHD. Studies correlating the impact of medication nonadherence on symptoms and impairments in adult ADHD are needed. Future studies should consider utilizing technology to document medication nonadherence, such as MEMS caps.