Health Topic

Dual Diagnosis

Many people with a mental illness also have problems with substance abuse. This is called dual diagnosis, or co-occuring disorders. Learn more.

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Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Dual Diagnosis

If you have a dual diagnosis, that means that you have both a mental disorder and a substance use disorder (SUD), either with alcohol or drugs. A dual diagnosis is a type of comorbidity, which is when someone has two disorders at the same time. Another name for this is co-occurring disorders.

Mental and substance use disorders often occur together. Many people who develop SUDs are also diagnosed with mental disorders. And the reverse is true; many people with mental disorders will develop an SUD. Having both types of disorders is even more common in teenagers, people with serious mental illness, and people with certain mental disorders.

Although these problems often occur together, this does not mean that one caused the other, even if one appeared first. In fact, it can be hard to figure out which came first. Researchers think that there are three possible reasons as to why they often occur together:

  • Common risk factors can contribute to both mental disorders and SUDs. These factors include: Genetics.
  • Stress.
  • Trauma, especially in childhood. Veterans with post-traumatic stress disorder (PTSD) are also at risk for SUDs

If you have a dual diagnosis, it is usually better to treat both conditions at the same time rather than separately. You and your health care provider can work on a treatment plan that fits your needs.The plan should take into account your age, which substance(s) you are misusing, and which specific mental disorder(s) you have. The plan may include:

  • Behavioral therapy, such as talk therapy (psychotherapy), long-term residential treatment (which combines housing and treatment services), and therapies to help you stay motivated to stick with your treatment plan.
  • Medicines. There are effective medicines that treat opioid, alcohol, and nicotine addiction. There are also medicines that can lessen the symptoms of many mental disorders. Some medicines may treat more than one disorder.
  • A referral to a support group. Support groups can give you emotional and social support. They are also a place where people can share tips about how to deal with day-to-day challenges.

It sits within Mental Health and Behavior and Substance Use and Disorders.

The lead U.S. institute for this subject is the National Institute on Drug Abuse.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Dual Diagnosis

36,527 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

Learn More

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Diagnosis, Dual (Psychiatry). These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Dual Diagnosis, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.