Co-Occurring Schizophrenia & Substance Use Disorder

People with substance use disorders (SUD) often have co-occurring mental health disorders, such as schizophrenia.1 This means that they have a dual diagnosis, or one or more mental health conditions that occur at the same time as one or more SUDs.1

If you or someone you know is struggling, you should know that treatment can help. This article will help you understand schizophrenia, the dual diagnosis of schizophrenia and addiction, and how to seek treatment for schizophrenia and addiction.

What is Schizophrenia?

woman sitting on sofa with her knees pulled up to her chest and head down, distressed by her ADHD and substance abuse symptoms

Schizophrenia is a serious mental illness and psychotic disorder that can co-occur with SUDs.1 It can cause significant dysfunction and includes a wide range of cognitive, behavioral, and emotional impairments.1 People with schizophrenia may struggle with their thoughts, in activities of daily living, relating to others, perceiving reality, and cognition.2

According to the American Psychiatric Association (APA), less than 1% of people in the United States has schizophrenia.2 Statistics show that schizophrenia tends to affect men and women equally but seems to have an earlier onset in males.2 People who have schizophrenia can feel like they’ve lost touch with reality, which can be distressing for both the person and their loved ones.3

What Are the Symptoms of Schizophrenia?

Schizophrenia can cause several symptoms that range in severity. The APA explains that symptoms fall into 3 main categories: positive symptoms (symptoms that are abnormally present), negative symptoms (symptoms that are abnormally absent), and disorganized symptoms (symptoms that cause bizarre, abnormal, or distorted cognition and behavior).2

The APA’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) provides diagnostic criteria for schizophrenia. People must display at least 2 of the following schizophrenia symptoms over a 1-month period, and must have at least one of the first 3 symptoms:1

  • Grossly disorganized or catatonic behavior
  • Delusions (meaning believing something that isn’t true or believing something is true when it isn’t)
  • Hallucinations (meaning you see, hear, feel, or smell things that aren’t there)
  • Disorganized speech (such as rambling on or incoherence)
  • Negative symptoms (meaning those that are lacking, such as diminished emotional expressions or lack of motivation)

These symptoms must cause significant impairment in the person’s ability to function in areas such as work, interpersonal relations, or self-care, and functioning must be significantly below the level prior to the onset of symptoms.1

It’s important to note that some symptoms can also occur in people who are intoxicated with certain substances, such as cannabinoids, cocaine, amphetamines, and hallucinogens, and can also occur in substance-induced psychosis.4 This is why diagnosing and treating co-occurring disorders can be challenging and why they require a proper and prompt diagnosis.

How is Schizophrenia Diagnosed?

Only a doctor or qualified mental health professional can diagnose schizophrenia. They use criteria from the DSM-5 to confirm a suspected diagnosis.

The DSM-5 explains that people must show ongoing signs of disturbance for at least 6 months, with at least one month of active symptoms outlined above.1 A doctor should provide a thorough medical exam to rule out other disorders that could resemble schizophrenia and rule out whether the symptoms were induced by substance use.1

The Relationship Between Schizophrenia and Drug or Alcohol Misuse

Schizophrenia and alcohol or drug misuse are closely related. People with schizophrenia are more likely to smoke, use alcohol heavily, use marijuana heavily, and use recreational drugs.5 Substance misuse can be a major contributor to early death and increased disability that frequently occurs in people with schizophrenia.5

People with a dual diagnosis of schizophrenia and SUD might wonder if one disorder caused the other, but there isn’t an established, direct causality, as co-occurring disorders tend to develop as a result of many various factors.5

How Alcohol Affects People with Schizophrenia

Alcohol is one of the most commonly used substances by people with schizophrenia, with one meta-analysis reporting a lifetime prevalence of alcohol use disorder (AUD) of 24.3% in people with this mental health condition.6 Alcohol does not cause schizophrenia, but it can worsen symptoms.1

Research has shown that alcohol misuse by people with schizophrenia is associated with many different problems and side effects, including:7

  • Increased likelihood of recurring psychiatric symptoms.
  • Psychosocial instability.
  • Other SUDs.
  • Violence.
  • Victimization.
  • Legal problems.
  • Medical problems such as HIV infection and hepatitis.
  • Family problems.
  • Institutionalization.

How Drug Misuse Affects People With Schizophrenia

Schizophrenia and drug use are often closely related. Research shows that individuals with schizophrenia commonly misuse drugs, especially marijuana and cocaine.8 Despite the high prevalence of drug use, it does not directly cause schizophrenia.9 Similar to alcohol use, drug use can worsen symptoms and overall outcomes of the disease.1

In addition, people with schizophrenia who use drugs can experience:1

  • Poorer outcomes in psychotic symptoms.
  • Higher rates of inpatient and emergency services utilization.
  • Difficulty with finding stable housing.
  • Higher rates of incarceration.
  • Greater risk for self-destructive and violent behaviors.
  • Victimization.
  • Suicide.
  • Poor physical health.
  • Cognitive impairment.
  • Employment problems.
  • Legal difficulties.
  • Unstable social relationships.
  • Poorer treatment compliance.

Can Drug Use Cause Schizophrenia?

Some researchers have hypothesized that drug use could be a potential contributor to the development of schizophrenia.10 Drug use directly impacts parts of the brain thought to be affected by disease processes in psychosis; while drug use could increase the risk of psychotic symptoms, using drugs does not directly cause schizophrenia.9,10 A complex interplay of different risk factors, including genes and environment, can influence the development of co-occurring SUD and schizophrenia.

Risk Factors for Co-Occurring Schizophrenia and Substance Use Disorder

Researchers have identified potential risk factors for co-occurring SUD and schizophrenia, which include:

  • Substance use: Research has found evidence that supports the relationship between SUD and the onset of schizophrenia if the onset of SUD occurs first.10 Substance use may contribute to the development of mental illness in general.9
  • Genetic vulnerability: Researchers believe that a combination of genetics and the environment can contribute to co-occurring disorders like schizophrenia and SUD.9
  • Brain area involvement: Areas of the brain that are affected by substances are also impacted by mental illnesses like schizophrenia.9
  • Environmental influences: This can include factors like chronic stress, trauma, adverse childhood experiences, and other influences.9

How to Treat Schizophrenia and Addiction

cropped image of a group therapy sessions

While treatment for co-occurring disorders can be challenging, research shows that treatment is effective, and outcomes can be even better for people once they stop substance use.10 Properly diagnosing a co-occurring disorder is important to avoid missing one disorder and to provide the right treatment.11  Integrated treatment is the advisable approach, according to the Substance Abuse and Mental Health Services Administration.1

Treatment often involves medication, as well as:1

  • Cognitive-behavioral therapy.
  • Group behavioral therapy.
  • Contingency management.
  • 12-Step facilitation.
  • Motivational enhancement.
  • Motivational interviewing.

Sunrise House Treatment Center, our New Jersey metro area inpatient rehab facility, offers different levels of addiction treatment and treatments for co-occurring disorders to help you or your loved one start the path to recovery. These include:

  • Medical detox to help you stop using substances and undergo withdrawal if deemed necessary for your situation. You will receive a private room and 24/7 medical supervision to keep you safe and comfortable.
  • Residential treatment, which can help you focus on recovery from co-occurring disorders. You’ll live onsite and participate in a variety of individual, group, and holistic therapy sessions to promote long-term recovery.
  • Aftercare to help ensure your ongoing recovery.

In the event that attending a residential treatment program is not an option, you can still obtain some level of addiction treatment that meets your unique needs. American Addiction Centers, Sunrise House’s parent company, has several facilities throughout the nation that offer additional levels of care, including outpatient treatment and sober living options.

If you or a loved one is struggling with schizophrenia and addiction, you can start the recovery process and get admitted today. You can also gather more information about insurance plans that cover treatment and paying for rehab, as well as Please call our free and confidential helpline at 928-900-2019 to start the treatment process at Sunrise House Treatment Center.

Was this page helpful?
Thank you for your feedback.

American Addiction Centers (AAC) is committed to delivering original, truthful, accurate, unbiased, and medically current information. We strive to create content that is clear, concise, and easy to understand.

Read our full editorial policy

While we are unable to respond to your feedback directly, we'll use this information to improve our online help.