Dual diagnosis is a term used to describe when a person is experiencing both mental health problems and substance misuse. It is also commonly referred to as co-morbidity and co-occurring mental health and substance use Examples of a dual diagnosis might include:
a mental health problem or disorder leading to or associated with problematic alcohol and/or other drug use
a substance use disorder leading to or associated with a mental diagnosis
alcohol and/or other drug misuse worsening or altering the course of a person’s mental illness.
Dual diagnosis is an evolving field and we are still learning to understand causal relationships between substance misuse and mental health problems, and how to develop effective strategies for prevention, treatment and recovery.
A mental illness is a disorder that affects the way a person thinks, feels and behaves.
There are many types of mental illness, which will affect each person differently. Some examples of mental illness include:
Drug use becomes problematic when this use negatively impacts a person’s life or the life of those around them. This might include:
the use of illegal drugs
the use of a legal drug without prescription or in excessive amounts
using a drug despite any problems caused by the effects of that drug.
People's experience of dual diagnosis vary. Someone might experience depression or anxiety when using alcohol. Others may find that their cannabis use makes their schizophrenia worse. It depends on the type of mental health problem and its symptoms, the drugs or alcohol used, and how these combine together. It also depends on the treatment or support the person receives. Some types of treatment may work for some people but not others.
Which comes first—mental illness or problematic drug use?
It can be difficult to determine which occurs first, the mental illness or the problematic drug use. As we’ve discussed, reasons and links between mental health and substance misuse will vary. Other factors like work, relationship difficulties, or other trauma may increase the risk of a person developing a mental illness or experiencing problematic drug use.