The onset of mental illness is often a very stressful time.  There are many challenges especially for people diagnosed with schizophrenia. If they lack access to proper mental health treatment or education about the illness, they are at increased risk of coping with drugs and alcohol. Drug and alcohol use can also lead to an earlier presentation of psychotic symptoms, induce psychotic relapse, or increase symptom severity.

Common substances abused by people with schizophrenia include alcohol, nicotine, cocaine, and cannabis. Substance abuse studies vary widely with claims ranging from 10% of 70% of people with schizophrenia having a problem.1 Researchers have found that over half of all people with schizophrenia abused at least one substance prior to the onset of the mental illness. People with schizophrenia also are 4.6 times more likely to be diagnosed with a substance use disorder than the general population.2

People with schizophrenia who abuse substances experience more cognitive impairment, more intense psychosis and higher rates of needing emergency services. They are also more likely to be incarcerated and experience legal troubles. Among people with schizophrenia, young men and people with lower levels of education are particularly at risk for developing a substance use disorder.3

Some researchers focus on the self-medication theory, asserting that people use drugs or alcohol to self-medicate when experiencing unpleasant symptoms or the side effects of antipsychotic medication.4 Others focus on genetic factors, asserting that people predisposed to develop schizophrenia are also at risk for substance use. Researchers further assert that environmental factors can play a role, as a majority of people with schizophrenia and substance abuse experienced a significant trauma earlier in life.

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Alcohol Abuse

Because alcohol is so readily available, it can become easier for people with schizophrenia to develop a dependence on it compared to illegal drugs. Roughly one-third of people with schizophrenia will develop alcohol use disorder at some point in their lives. Often the alcohol abuse will precede the development of schizophrenia, which suggests that the self-medication theory is not always correct.5

Nicotine Abuse

Forty-four percent of cigarettes sold in the United States are bought by people with a psychiatric disorder. Seventy percent of people with schizophrenia have nicotine-dependence, which can make them more likely to experience a relapse of symptoms. People with schizophrenia who smoke are more likely to have hallucinations, delusions, and disorganized speech and require higher dosages of antipsychotic medications.6

Cannabis Abuse

Cannabis use has also been shown to potentially worsen or accelerate the development of psychotic symptoms in certain groups. One study found that 53% of people experiencing their first psychotic episode also qualified for cannabis use disorder.7

Cocaine Abuse

Schizophrenic patients with cocaine use disorder are at increased risk of suicide, low-treatment compliance, and hospitalization. They are also more likely to come from low-income communities and have had trauma earlier in life. People may use cocaine to cope with the negative symptoms of schizophrenia and feelings of dysphoria.8

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Treatment Options
Because schizophrenia and substance abuse occur so frequently together, it’s important to treat both disorders simultaneously. If a person stops substance use without being connected to proper medication and treatment for mental health, they are likely to relapse. And if a person is given mental health treatment without addressing substance abuse, they are unlikely to adhere to treatment. This is why it’s important to treat both disorders at concurrently.9

The first step of dual diagnosis treatment is typically the detox period, to ensure the patient is treated for withdrawal symptoms. Detox also enables medical professionals to rule out the possibility that psychotic symptoms being caused by drug or alcohol abuse rather than schizophrenia itself. After the initial detox and evaluation, interventions in dual diagnosis programs may involve:

  • cognitive behavioral therapy
  • adult daily living skills training
  • family involvement
  • substance refusal skills training
  • medication management
  • motivational interviewing techniques

Treating both disorders together may also help patients improve self-care habits like sleep and nutrition and treat other chronic medical conditions that have developed in conjunction with poor mental health and substance abuse.

With the right support and treatment for both disorders, people with schizophrenia can learn to manage symptoms without the use or drugs or alcohol. They’re also less likely to experience relapse or worsening symptoms. If you have a loved one with co-occurring disorders, take steps today to educate yourself about treatment programs in your community. For more resources, visit or NAMI ( Both sites can connect you to local therapists and other helpful organizations.

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Last Updated: Oct 2, 2020