Schizophrenia and Substance Use Disorder: What’s the Connection?

For many reasons, substance use and mental health disorders often happen together. Having schizophrenia and substance use disorder (SUD) at the same time is called a dual diagnosis or co-occurring disorders. Some people start using alcohol or drugs as a temporary escape from schizophrenia, while for others, substances may trigger psychosis and other mental health symptoms. Over time, substance use can make living with schizophrenia more difficult.

In this article, we’ll explain how schizophrenia and SUD affect each other, why they often occur together, and why treating both at the same time is key to feeling better.

Understanding Schizophrenia and Substance Use Disorder

Schizophrenia is a mental health condition that affects how a person thinks, feels, and behaves. The condition includes psychotic symptoms, like hallucinations (hearing voices or seeing things that aren’t there) or delusions (holding strong beliefs that aren’t based in reality). Schizophrenia can also make a person feel emotionally numb, withdraw from others, or lack motivation to do even simple tasks.

In SUD, a person keeps using drugs or alcohol in a way that harms their life. This can involve substances like cannabis, opioids, or other drugs.

Having both schizophrenia and SUD doesn’t mean that one caused the other. These conditions often develop together due to a mix of shared risk factors, like family history, brain chemistry, or stressful life events. Experiences such as trauma or high stress can increase the chance of someone developing mental illness and also misusing substances.

Sometimes, schizophrenia comes first, and drug or alcohol use starts later. In other cases, heavy substance use — especially using cannabis during the teen years — may lead to the onset of schizophrenia. The connection is complex, and it’s not always clear which starts first.

How Common Is Schizophrenia Plus SUD?

It’s quite common to have both schizophrenia and SUD. Researchers estimate that in the U.S., nearly half of people with schizophrenia will have SUD at some point in their lives. This means that people with schizophrenia are about three to six times more likely to have SUD compared to people without schizophrenia.

Why People With Schizophrenia May Use Substances

People with schizophrenia may use alcohol or drugs even though it can make symptoms worse. There are several reasons why this happens.

The Self-Medication Hypothesis

People with schizophrenia may use substances to cope with the overwhelming symptoms of schizophrenia or the side effects of antipsychotic medications. This is also known as self-medicating.

For example, someone might use drugs to cope with the positive symptoms of schizophrenia, such as hearing voices or feeling paranoid. Others may use substances to numb negative symptoms, which include feeling flat, unmotivated, or disconnected.

Some antipsychotic medications can cause side effects like drowsiness, restlessness, and weight gain. A person may turn to certain drugs to feel more awake, relaxed, or in control.

Stress and Environmental Factors

Life with schizophrenia can be isolating and stressful. Stress is a major trigger for substance use. People may use drugs to cope with poverty, loneliness, trauma, or lack of stable housing. Facing stigma, job loss, or difficulty finding support can add to the problem, creating a cycle that worsens both mental health and substance use.

Genetic Risk for Substance Use

Some people are born with genes that raise their risk of both schizophrenia and SUD. These genes can affect how the brain uses dopamine, a brain chemical involved in both psychosis and feelings of reward.

Reward Circuitry Dysfunction

Even without drug use, schizophrenia can change how the brain experiences pleasure or stress.

The brain’s reward system, which depends on chemicals like dopamine, has been shown to work differently in people with schizophrenia. This can make it hard to feel motivated or take pleasure in activities. When people can’t experience the joy and energy they once had, some may turn to substances to try to boost these brain chemicals.

How Does Substance Use Affect Schizophrenia?

Substance use or misuse can affect anyone’s life, but for people with schizophrenia, the impact is often greater. The more someone uses drugs or alcohol, the higher the risk of problems with work, relationships, health, and safety.

Certain drugs, such as cannabis or amphetamines, can worsen psychotic symptoms. These substances raise dopamine levels in the brain, which are already higher than usual in people with schizophrenia. This can lead to stronger symptoms, such as feeling paranoid, hearing voices, or having trouble thinking.

Substance use may also make medications less effective or lead to missed or irregular doses. If medications aren’t taken as prescribed, symptoms may return, or psychotic episodes might happen more often.

People with both mental health conditions are also more likely to stop treatment for schizophrenia or drop out of treatment programs. This can lead to more relapses, more time in the hospital, and more stress overall.

The Importance of Treating Both Conditions Together

When someone has both schizophrenia and SUD, leaving one condition untreated can make the other worse. That’s why doctors and researchers recommend integrated treatment — treating both conditions at the same time, ideally with the same care team. This approach usually combines medications, therapy, and community support.

Medications

Antipsychotic medications are the most effective medicines for managing symptoms of schizophrenia. Certain antipsychotics, such as clozapine, may be helpful if other medications haven’t worked in the past. For opioid or alcohol use disorders, other medications may be added to help reduce cravings and prevent relapse.

Therapy and Support

Some forms of talk therapy, such as cognitive behavioral therapy (CBT), can teach coping skills and help change harmful thinking patterns. Some treatment programs also involve contingency management, which use rewards to motivate people to stay away from substances.

Community Support

Case managers and rehabilitation programs can help with housing, jobs, transportation, and other basic needs. Peer support groups — especially those focused on dual diagnosis — also offer encouragement and connection from others who understand. For more help, national resources like SAMHSA and the National Alliance on Mental Illness can be valuable.

Tips for Care Partners and Family Members

Supporting someone with both schizophrenia and SUD is hard, and there’s no one right way to do it. It’s normal to feel worried, frustrated, or overwhelmed at times. If you don’t know where to start or what to try next, here are a few tips:

• Learn about both conditions so you can better understand what your loved one is going through. Patience and empathy may then come more easily.
• Encourage treatment, but avoid blame or pressure.
• Set clear boundaries to protect your well-being, especially when it comes to safety or substance use at home.
• Take care of yourself, because your mental health matters, too. Talking with a therapist or finding a support group for families or caregivers can help.
• Celebrate progress, no matter how small. Recovery takes time, and every step forward counts.

You are not alone. Support is available for both you and your loved one.

Talk With Others Who Understand

On MySchizophreniaTeam, the social network for those with schizophrenia and their loved ones, people come together to ask questions, give advice, and share their stories with others who understand life with schizophrenia and other mental health conditions.

Do you or someone you care about have a dual diagnosis of schizophrenia and SUD? What have been the biggest challenges? Share your thoughts or start a conversation in the comments below.