Dual Diagnosis / Co-occurring Disorder (Substance Abuse and Mental Illness)

What is Dual Diagnosis?

Dual diagnosis is a term used to describe people who have both a mental illness and problems with drugs and/or alcohol. It may also be called a co-occurring or co-existing disorder. Recovery and treatment must address both the substance disorder and the psychiatric disorder.

Individuals receiving a dual diagnosis may have one or more psychiatric disorders in addition to the substance use disorder. The complex relationship between psychiatric illness and substance abuse or dependence takes a toll in multiple ways:

  • A person with a psychiatric illness may drink or use drugs to lessen pain or ease other symptoms of their condition. Such “self-medication” of their anxiety, depression or other illness may help them feel calmer or better for a short time, but it doesn’t treat the underlying condition and may make the condition worse.
  • Frequent self-medication may ultimately lead to physical and/or psychological dependence on alcohol or drugs, turning one problem into two.
  • Drugs and alcohol can worsen underlying mental illnesses. This can happen both during intoxication (e.g., a person with depression becomes suicidal in the context of drinking alcohol) and during withdrawal from a substance (e.g., a person with panic attacks experiences worsening symptoms during heroin withdrawal).
  • Drugs and alcohol can trigger the first onset of a psychiatric condition in someone without mental illness. For example, if a teenager or young adult hears voices after taking drugs and becomes paranoid, that substance-induced reaction could prompt a first episode of psychosis.
  • In other cases, alcohol or drug dependence is the primary condition. A person with a substance use disorder may develop symptoms of a psychiatric disorder such as episodes of depression, hallucinations or delusions.

Individual and societal impacts

People who are actively using drugs or alcohol are less likely to follow through with their treatment plans. They’re less likely to take their medications as directed and more likely to miss appointments, leading to more psychiatric hospitalizations and other adverse outcomes. Similarly, active substance abusers are less likely to receive adequate medical care and have greater chances of experiencing severe medical complications and early death.

Individuals with mental illness who abuse drugs and/or alcohol, and who are untreated are:

  • More prone to impulsive and potentially violent acts.
  • More likely to attempt suicide and to die from their suicide attempts.
  • More likely to become physically dependent on their substance of choice.
  • Less likely to achieve lasting sobriety.

Undiagnosed, untreated or undertreated co-occurring disorders also increase likelihood of incarceration and homelessness. While treatment is proven to be effective, many who need it don’t have access to care. This burdens individuals, their families and society at large.

How Common is Dual Diagnosis?

Recent scientific studies have suggested that nearly one-third of people with all mental illnesses and approximately one-half of people with severe mental illnesses (including bipolar disorder) and schizophrenia) also abuse substances. A report published in the Journal of the American Medical Association documented that 37 percent of alcohol abusers and 53 percent of drug abusers also have at least one serious mental illness. Approximately 8.9 million adults are diagnosed with both a mental and substance use disorder. However, only 7.4 percent of individuals receive treatment for both conditions and more than half – 55.8 percent – receive no treatment at all.


Upon initial examination, it may be difficult for a physician to determine if a person’s primary problem is substance abuse or a psychiatric disorder. Many symptoms of severe substance abuse are common to other psychiatric conditions. Therefore, the individual may have to undergo withdrawal from alcohol and/or drugs before a doctor can accurately identify an underlying mental issue.


Treatment that addresses psychiatric conditions and substance use at the same time – integrated treatment – is most productive. This approach offers lower costs and better outcomes such as:

  • Reduced substance use
  • Improved psychiatric symptoms and functioning
  • Decreased hospitalization
  • Increased housing stability
  • Fewer arrests
  • Improved quality of life

Many people choose to seek assistance in ending their drug and alcohol abuse through inpatient detoxification at a hospital or a detoxification facility. Supervised treatment with the appropriate medications can significantly ease symptoms and avoid serious complications of drug and/or alcohol withdrawal. It can take a few days to a week or more depending on the substances and amount of time abused.

Once detoxification is complete, the patient can undergo simultaneous rehabilitation for the alcohol or drug problem and treatment for the psychiatric disorder. While it is possible to treat people with mental illness while they are still using, treatment of mental illness is far more effective when the individual is sober and fully participating in treatment.

Multipronged rehabilitation

Rehabilitation for substance abuse typically incorporates individual and group psychotherapy, education about alcohol and drugs, exercise, proper nutrition, and participation in a 12-step recovery program such as Alcoholics Anonymous. The objective is not simply to refrain from drugs and alcohol, but to learn to live life without them.

Psychiatric treatment

The nature and severity of the psychiatric illness and the substance use disorder, associated risks or complications, and the individual’s treatment history will help determine the appropriate level of care – inpatient treatment, partial hospitalization or outpatient treatment.


Some people find therapy to be a helpful part of maintaining their sobriety. This can include individual therapy (e.g., cognitive behavioral therapy) as well as self-help groups such as Alcoholics Anonymous, Narcotics Anonymous or Smart Recovery.


Medications can be helpful in maintaining sobriety as well as in treating the psychiatric disorder. A physician may prescribe medications to treat people with alcoholism or other addictions. The complexity of choices makes it advisable for any individual with dual diagnosis and their loved ones to discuss medication management strategies with their doctors.

Family and social supports

Participation in education, counseling sessions and support groups for the patient’s family also fosters successful rehabilitation for substance abuse and treatment for a psychiatric problem.

Find help for a dual diagnosis



National Alliance on Mental Illness

The Kim Foundation


Helpful Resources:

Alcoholics Anonymous



Narcotics Anonymous


Smart Recovery



Other resources/reading: