We've all heard the term addiction used to describe people who abuse substances, such as alcohol or drugs, and we know that the drugs people can become addicted to can be both prescription and illegal. The term Concurrent disorders is less understood.

Concurrent disorders describes a condition in which a person has both a mental illness and a substance use problem. This term is a general one and refers to a wide range of mental illnesses and addictions. For example, someone with schizophrenia who abuses cannabis has a concurrent disorder, as does an individual who suffers from chronic depression and who is also an alcoholic. Treatment approaches for each case could be quite different. Another term for concurrent disorder is comorbidity. In the United States, the terms dual diagnosis, dual disorder, or mentally ill chemical abuser are used.

People with mental illness have much higher rates of addiction than people in the general population.* Similarly, individuals with an addiction have much higher rates of mental illness than people in the general population. The question of which typically occurs first, the addiction or the mental illness, is similar to that of the chicken and the egg. While certain substances, like alcohol, a depressant, can cause symptoms of depression, many develop addictions because of their attempt to “self-medicate” for their mental illness, i.e., Someone with an anxiety disorder may smoke cannabis in an attempt to decrease their anxiety.

*In the general population rates of substance abuse are 16.7% but range from under 20% (Hall, Popkin & DeVaul, 1977) to over 65% (Ananth et al., 1989) for people with serious mental illness.