Mental Comorbidities, Psychotropic Medication Use and Healthcare Resource Use in Autism Spectrum Disorder: A Matched Cohort Study in the United Kingdom.

Background: Psychiatric comorbidities and use of psychotropic medications are common among patients with autism spectrum disorder (ASD). Most previous work in this area used data from the United States, and few studies have compared medication use in ASD to control groups.

Objectives: The objective of this study was to investigate psychiatric comorbidities, psychotropic medication use and resource utilization in patients with ASD in the United Kingdom (UK), as well as to compare these outcomes to the general population and to patients with attention deficit hyperactivity disorder (ADHD). We also estimated associations between patient characteristics and the probability of being prescribed psychotropic medications in ASD.

Methods: We conducted a cohort study using primary care data from the Clinical Practice Research Datalink (CPRD) database. The main study period was the calendar year 2015. We identified a prevalent cohort of patients with ASD and two comparison cohorts -- namely, a general population and an ADHD cohort, both matched by age, sex and region. We described mental comorbidities, use of psychotropic medications, and healthcare utilization (GP visits and referrals to secondary care) in all three cohorts. For the ASD cohort we used regression models to investigate patient characteristics associated with psychotropic medication use, polypharmacy (2 classes of psychotropic medications at the same time) and the number of visits to the GP. Lastly, we compared medication and resource use in ASD to the control cohorts using conditional logistic regression models.

Results: A total of 10,856 ASD patients were included in the study. The majority were male (81%) and the mean (SD) age was 18.76 (11.86) years. Psychiatric comorbidities were recorded in 41.5% of all ASD patients, with sleep disturbances (14.9%) and ADHD (13.8%) being the most common. Thirty-two percent of ASD patients received a psychotropic medication prescription, with anxiolytics/sedatives/hypnotics (14.2%), antidepressants (12.8%) and antipsychotics/tranquilizers (8.3%) being the most common. Eighty-six percent of ASD patients had visits to primary care, while 18.9% were referred to secondary care. Increased age and female gender increased the likelihood of both psychotropic medication use and healthcare resource utilization, as did the majority of the psychiatric comorbidities studied.

ASD patients were more likely to take psychotropic medications and visit primary care more frequently than the general population. However they were less likely to have these outcomes compared to ADHD patients. For drug use, this was largely driven by the prescription of stimulants.

Limitations: The study is limited to data entered in primary care.

Conclusions: People with ASD were more likely to receive medication and use healthcare resources than the general population, but less likely, compared to people with ADHD. Psychiatric comorbidities and psychotropic medication use are common in ASD in the UK. In a 1-year period, 1/3 of ASD patients received a primary care prescription for a psychotropic medication.