Electronic Thesis and Dissertation Repository


Master of Science


Epidemiology and Biostatistics


Dr. Evelyn Vingilis, C. Psych


The vast majority of studies on attention-deficit/hyperactivity disorder (ADHD) are based on samples with inherent age, sex, and referral biases. Therefore, the current study used population-based data to 1) estimate the prevalence of adult ADHD (as well as previous diagnosis and medication use using an ADHD screener) and co-occurring psychiatric distress and substance use in Ontario 2) examine the sex differences in ADHD screening status and co-occurring psychiatric distress and substance use and 3) model ADHD screening status as a risk factor for psychiatric distress using the 2011 cycle of the Centre for Addiction and Mental Health Monitor. A positive ADHD screen was significantly associated with psychiatric distress and substance use; however the majority of those with a positive ADHD screen did not exhibit these issues. Symptom overlap and lack of diagnosis and treatment may have contributed to the findings in this sample. Importantly, the effect of age must also be accounted for in future studies where sample size permits.