Medications for attention-deficit/hyperactivity disorder in individuals with or without coexisting autism spectrum disorder: analysis of data from the Swedish prescribed drug register
Johansson V, Sandin S, Chang Z, Taylor MJ, Lichtenstein P, D’Onofrio BM, Larsson H, Hellner C, Halldner L.
J Neurodev Disord. 2020 Dec 23;12(1):44.
Commentary* by Dr. Margaret Weiss: Given how common ADHD + ASD is, it is remarkable how little consistent data we have about the risks and benefits of pharmacological treatments or comparison between treatments. This suggests that in the community this lack of data and lack of guidelines are leading to clinicians experimenting with a wide range of adaptations to usual treatment for ADHD alone.
Background: Clinical studies found that medication for attention-deficit/hyperactivity disorder (ADHD) is effective in coexisting autism spectrum disorder (ASD), but current research is based on small clinical studies mainly performed on children or adolescents. We here use register data to examine if individuals with ADHD and coexisting ASD present differences in the prescribing patterns of ADHD medication when compared to individuals with pure ADHD.
Methods: Data with information on filled prescriptions and diagnoses was retrieved from the Swedish Prescribed Drug Register and the National Patient Register. We identified 34,374 individuals with pure ADHD and 5012 individuals with ADHD and coexisting ASD, aged between 3 and 80 years. The first treatment episode with ADHD medications (≥ 2 filled prescriptions within 90 days) and daily doses of methylphenidate during a 3-year period was measured. Odds ratios (ORs) were calculated for the likelihood of being prescribed ADHD medication in individuals with and without ASD and Wilcoxon rank-sum test was used to compare group differences in dose per day.
Results: Individuals with ADHD and coexisting ASD were less likely to start continuous treatment with ADHD medication (ADHD 80.5%; ADHD with ASD 76.2%; OR, 0.80; 95% confidence interval, 0.75-0.86), were less likely to be prescribed methylphenidate, and were more commonly prescribed second line treatments such as dexamphetamine, amphetamine, or modafinil. No group difference was observed for atomoxetine. In adults with ADHD and coexisting ASD, methylphenidate was prescribed in lower daily doses over three years as compared to individuals with pure ADHD.
Conclusions: The findings indicate that there are differences in the medical treatment of individuals with or without ASD. If these differences are due to different medication responses in ASD or due to other factors such as clinicians’ perceptions of medication effects in patients with ASD, needs to be further studied.
* Abstracts are selected for their clinical relevance by Dr. Margaret Weiss, Director of Clinical Research, Child Psychiatry, Cambridge Health Alliance, Harvard University. Her commentary reflects her own opinion. It is not approved or necessarily representative of the CADDRA board.