Prescribing of drugs for attention-deficit hyperactivity disorder in opioid maintenance treatment patients in Norway

Abstract

Background: Attention-deficit hyperactivity disorder (ADHD) is a risk factor for development of substance use disorders. Treatment of ADHD with psychostimulants in patients on opioid maintenance treatment (OMT) has been restricted in Norway. We examined use of prescribed drugs for ADHD in OMT patients, and assessed co-medication with other psychotropics. Methods: Data were drawn from the nationwide Norwegian Prescription Database (NorPD), which includes all prescriptions filled at pharmacies. The study population was people ≥18 years on OMT during 2008-2010. Results: In 2010, 6,116 patients received OMT and 2.8% of these patients also received ADHD drugs. This is seven times greater than in the gender-and age-specific general population of Norway. Prevalence was higher in the youngest patients, while there was no gender difference. Methylphenidate was the most commonly used drug for ADHD in OMT patients, followed by atomoxetine. 60% of OMT patients filled at least one prescription for antidepressants, anxiolytics or hypnotics and percentages were similar for users and non-users of ADHD drugs. Conclusion: Treatment with ADHD drugs was higher in OMT patients than expected from the general population, but was relatively low compared to the prevalence of ADHD in patients with substance use disorders reported in the literature.