Dutch study identifies medication adherence deficits in adults with ADHD

Attention-deficit/hyperactivity disorder (ADHD) can have a tremendous impact on a patient’s life. In adults, ADHD has been linked to increased morbidity and mortality, divorce rates, criminality, and other negative social outcomes. However, little is known about the effects of long-term compliance with prescription psychostimulants on adults with ADHD.

A recent study in the Netherlands examined the persistence and adherence to psychostimulants on the psychological well-being of adult patients with ADHD. The results were published in the Journal of Clinical Psychopharmacology.

Research in this area has primarily focused on adherence or persistence. In this context, adherence is the general patient compliance with prescribed timing, dose, and frequency. Persistence refers to the time from initiation to discontinuation of therapy. Prior studies have shown that adult patients with ADHD who receive at least 2 years of psychostimulant treatment had better general function than those treated for less than 2 years.

In this study, researchers looked at adult patients with either an initial diagnosis of ADHD in adulthood or a previously established diagnosis of ADHD who received specialized outpatient treatment at PsyQ, an adult ADHD program in The Hague Center, the Netherlands. Patients who were discharged between August 2012 and January 2013 were given a baseline questionnaire. Follow-up telephone interviews were conducted at 6 months, 1 year, and 3 years after discharge.

Persistence was gauged by asking whether patients were still taking the prescribed medication. Adherence was expressed as the percentage of times the drug was taken during a month’s time. An adherence rate >80% was considered optimal.

The researchers found that 78% used a psychostimulant prescribed by a psychiatrist at the time of discharge. Of those on psychostimulants, almost 50% were still using the medication at 3 years. Adherence rates were good in those who persisted with therapy.

Women and persons with a middle educational level were near-significantly associated with nonpersistence. Patients with a higher educational level and those with a combined ADHD subtype were associated with nonadherence. Nonadherence was related to poorer general functioning, mood, and sleep quality.

“[The study] has shown that persistence rates drop after discharge, but those who persist also have good adherence rates,” the authors concluded. “Women, higher-educated patients, and those with a combined ADHD subtype should be informed about the risks of nonadherence for their psychological health.”