Medication adherence and persistence in children and adolescents with attention deficit hyperactivity disorder (ADHD): a systematic review and qualitative update.

Low medication-adherence and persistence may reduce the effectiveness of ADHD-medication. This preregistered systematic review (PROSPERO CRD42020218654) on medication-adherence and persistence in children and adolescents with ADHD focuses on clinically relevant questions and extends previous reviews by including additional studies. We included a total of n = 66 studies. There was a lack of consistency in the measurement of adherence/persistence between studies. Pooling the medication possession ratios (MPR) and using the most common adherence definition (MPR ≥ 80%) indicated that only 22.9% of participants had good adherence at 12-month follow-up. Treatment persistence on medication measured by treatment duration during a 12-month follow-up averaged 170 days (5.6 months). Our findings indicate that medication-adherence and persistence among youth with ADHD are generally poor and have not changed in recent years. Clinicians need to be aware that various factors may contribute to poor adherence/persistence and that long-acting stimulants and psychoeducational programs may help to improve adherence/persistence. However, the evidence to whether better adherence/persistence contributes to better long-term outcomes is limited and requires further research.