Mr. Ken Kilbride:

People with ADHD will overindex for substance misuse. The vast majority of people with ADHD are undiagnosed. However, they will see they are different from their peers, having more challenges in life around, as Dr. Morris was saying, leaving jobs, having more jobs, marital difficulties and conditions like that. They know there is something happening in their lives so they start self-medicating, primarily around alcohol and cannabis.