Factors Associated With Medication Adherence Among Patients With Attention-Deficit/Hyperactivity Disorder (ADHD)

Attention-Deficit/Hyperactivity Disorder (ADHD) is a common behavioral health condition that impacts 5% to 8% of children and 2.5% of adults worldwide. The symptoms of ADHD are effectively managed with medication, yet patients with ADHD may inconsistently take their medication. We assessed medication adherence among patients with ADHD and identified factors associated with medication adherence that may be utilized to optimize adherence.

This is a retrospective, observational study among patients aged 4 years and older with a diagnosis of ADHD at primary care and multispecialty outpatient clinics during May 2021 to May 2023. We assessed sociodemographic characteristics, stratified by medication adherence status (Percentage of Days Covered ≥ 80%) using simple proportion, Student's t-test, and Chi-square test. We conducted univariable and multivariable logistic regression analyses to assess potential medication adherence factors, including sociodemographic characteristics, depressive symptoms, suicide risk, health service utilization, and social determinants of health (SDOH).

We found 7,661 patients diagnosed with ADHD, with a mean (SD) age of 21.8 (14.8) years. The ADHD prevalence was 5.5% for patients aged 4 to 12, 4.4% for 13 to 17, and 0.8% for 18+ years old. Most patients were male (56.9%), non-Hispanic White (37.6%), and privately insured (55.1%). Among these patients, only 4,242 (55.4%) were treated with medication. Among 4,011 patients with medication adherence information, the average adherence rate was 56%, and only 1,113 patients (27.5%) met our threshold for adherence to ADHD treatment (80%). Adherence was positively associated with being adults, having more BH and PCP visits, and negatively associated with racial and ethnic minorities and more severe depressive symptoms.

Only half of patients with ADHD were treated with medication. Of those treated, less than a third adhered to medication. Age, race and ethnicity, depressive symptoms, and BH and PCP visits were statistically associated with medication adherence. Healthcare providers may need to address factors such as coexisting depressive symptoms, and unmet SDOH needs to improve medication adherence among patients with ADHD. Also, patients reaching adolescence may need enhanced medication management.