When someone has both a substance use problem and a mental health problem, it is called a concurrent or co-occurring disorder. Sometimes substance use can cause a mental health problem, or sometimes a mental health problem may lead people to use substances to relieve their symptoms.
There are a number of reasons why people often have both a substance use problem and a mental health problem:
A person with a mental health problem may use substances to cope with the symptoms of the disorder. For example, someone with an anxiety disorder may use alcohol to feel more at ease in social situations.
Substance use problems may lead to conditions that put a person at risk of developing a mental health problem. For example, homelessness and isolation, which may result from substance use, may lead to major depression.
Having either a substance use or a mental health problem greatly increases the possibility of having the other problem. These problems can look very similar, which makes it difficult for family members and professionals to know whether a person is experiencing a substance use problem or a mental health problem—or both.