This page is based on the Alcohol and Drug Foundation (ADF) publication, Your guide to mental health and alcohol and other drug problems, which is available for purchase from the ADF Shop.
People who have problems with alcohol and other drugs (AOD) may also have mental health issues. This is called 'dual diagnosis'. It is also sometimes called 'comorbidity', 'comorbid disorders' or 'co-occurring disorders'.
A dual diagnosis could involve misuse of legal drugs (e.g. alcohol or prescription drugs) or illegal drugs (such as cannabis or methamphetamines). Mental health issues may include conditions such as anxiety, depression or psychosis.
Which comes first: problematic drug use or mental illness?
It can be difficult to tell which comes first as there are many reasons for a dual diagnosis. There may also be other issues that increase the risk, for example:
What are the effects of a dual diagnosis?
Mental health problems and problematic AOD use affect the person experiencing the problem and also those around them.
For example, they may have problems with relationships, education or employment. The impact for an individual can depend on:
Identifying a dual diagnosis can be complicated. The person making the diagnosis needs to decide whether the client’s issues are due mainly to drugs or mental illness, or a combination. Drugs can sometimes mask or imitate mental health problems.
People with a dual diagnosis may find it difficult to comply with treatment because of the combination of conditions. This can extend the length and severity of their condition.
It is important to treat both problems, rather than focusing on one and hoping that the other one will improve along with it.
Risk of relapse
A dual diagnosis increases the risk of relapse for either condition. The relapse of one will increase the chance of relapse of the other condition.
Interactions of conditions
AOD dependence and mental illness are long-term conditions that can interact and impact on each other. One may increase the risk of the other, or cause an existing disorder to become more of a problem.
Overdose and drug interaction
Taking prescribed medication along with alcohol or illicit drugs can be dangerous. The combination can cause unexpected side effects or reduce the effectiveness of important medication.
To reduce the risk of overdose or drug interactions, the prescriber must be told about regular (or likely) use of AOD, so they can adjust the dose of the prescription.
People with mental health issues, and people with AOD problems are both often stigmatised within the community. This means that those with a dual diagnosis may be doubly stigmatised.
Peer support groups that deal with either condition—or specifically with dual diagnosis—may be able to help people deal with stigmatisation. Health practitioners should also be able to offer advice and assistance.
Other consequences of dual diagnosis
People with dual diagnosis also experience higher rates of:
How is a dual diagnosis identified?
A health professional will need to carry out a detailed assessment and discussion to identify all mental health and AOD problems.
Sometimes the symptoms of mental health conditions are similar to those of AOD problems, so it can take time to identify the underlying problems.
How is a dual diagnosis treated?
For the best chance of a full recovery, both conditions should be treated at the same time, so treatment by both a mental health and a drug treatment doctor or service, may be needed. Good communication between all treatment professionals is important.
For complex cases, a service specialising in dual diagnosis can provide integrated treatment.
Where can I get help?
Local self-help services and support groups can help. Find assessment and treatment services in your area.
Many services can be accessed anonymously through telephone services, but face-to-face treatment will have the best results.
Start by contacting your family doctor or community health centre. They may not be able to treat you directly, but can refer you to an appropriate service.
The best treatment is likely to be through mental health and drug treatment services, often located in hospitals or community centres. Some may even have a dual diagnosis specialist. If more than one service in involved, they should work in partnership and include you in decision-making.
Do you have a dual diagnosis?
If you have a dual diagnosis, it is important that you learn to deal with your symptoms, and to develop coping strategies and relapse prevention skills.
Seek assistance and support from friends, family and health professionals to support you through treatment and enhance your quality of life.
Are you supporting someone with a dual diagnosis?
A dual diagnosis doesn't just affect the person with the diagnosis, it also affects all the people around them. If your friend or family member has a dual diagnosis, you can help them, and help yourself, by:
Alcohol and other drug information and support services can provide information, support, treatment and referral.
For mental health services, contact:
The Mental Health Carers ARAFMI This website provides links to services in each region of Australia.
Read our fact sheet 'What is dual diagnosis?'.
Last updated: 9 June 2016