What Is the Relationship Between Substance Use Disorder and Schizophrenia?
Substance use disorder (SUD) is an illness that impacts your brain and how you behave. It is also called addiction or substance abuse. It leads to a loss of control over use of substances like drugs and alcohol. While addiction is the most serious form of SUD, symptoms could also be milder than addiction.1
Having SUD along with a mental health illness such as schizophrenia is called having co-occurring mental disorders. You can treat both conditions with medicine and behavioral therapies.1
What research shows about the link between SUD and schizophrenia
Research has found many people with schizophrenia also have SUD. A 2018 review shows that 42 percent of those living with schizophrenia have SUD. The top substances used by this group are:2
- Illegal drugs
- Cannabis
- Alcohol
- Stimulants
Experts also found that people having their first psychotic episode are more likely to:3,4
- Use cannabis daily
- Smoke tobacco
- Drink alcohol
This is compared with those without psychotic disorders. Some experts even think a link exists between the use of cannabis and tobacco at a younger age and the risk of developing schizophrenia.3,4
The connection between SUD and schizophrenia
A number of factors may contribute to the co-occurrence of SUD and schizophrenia.
External stress
Those prone to developing schizophrenia because of genetics or other factors may develop it when exposed to external stress, like substance use. The substance can act as a trigger for the disease.3,4
A build-up of challenges
Your risk of developing schizophrenia could increase when you face many challenges, such as:3,4
- Trouble with thinking
- Struggles at school or work
- Poverty
Self-medication
People with schizophrenia may use substances to cope with their symptoms or side effects of treatment. But there is not a lot of evidence at this time to support this theory.3
Reward-circuit issues
SUD and schizophrenia may share a common underlying problem in the way certain parts of the brain work. More precisely, it points to issues with the brain’s reward circuit. This is involved in how we feel pleasure and motivation.3,5
How SUD affects schizophrenia
SUD does not directly cause schizophrenia. But regularly using alcohol and illegal drugs may worsen psychotic episodes or trigger more of them. These episodes appear to be linked to:6
- Cannabis
- LSD
- Other drugs that cause hallucinations
Compared with people who have schizophrenia alone, those who have both schizophrenia and SUD have higher rates of:2
- Hospital stays
- Homelessness
- Aggression
- Violence
- Being sent to jail or prison
- Thoughts of suicide
Diagnosing and treating SUD and schizophrenia
If a doctor has diagnosed you with both schizophrenia and SUD, you will need treatment for each condition. It is best to treat them at the same time. But they are most likely treated with different doctors.1
Symptoms between schizophrenia and SUD often overlap. This can make it hard for doctors to diagnose each condition separately. They may:1,7
- Screen for alcohol and drugs
- Do a physical exam
- Do a psychiatric exam
Once diagnosed, you will need a custom treatment plan. It should be based on your mental disorder and the substance misused. The plan will likely involve:1
- Behavioral therapies. There are different types of therapies that you may complete alone or with medicine. They include talk therapy, practicing mindfulness, and learning skills to control strong emotions and change behaviors.
- Medications. Prescription drugs can help treat addiction to opioids, alcohol, and nicotine. They can also ease schizophrenia symptoms. You may be able to take medicine that treats more than 1 condition.