Schizophrenia, or schizophrenia spectrum disorder, is a serious mental illness affecting 24 million people worldwide.

If you live with schizophrenia, your ability to relate to reality is significantly impaired. This can be highly distressing for you and your loved ones.

Data from 2013 revealed that schizophrenia was one of the top 25 causes of disability worldwide and suggested there aren’t enough adequate healthcare services available to those with schizophrenia.

People with schizophrenia are significantly more likely to also have substance use disorder (SUD), which includes the more specific diagnosis of alcohol use disorder (AUD).

Schizophrenia in combination with alcohol use, and particularly AUD, can have serious health ramifications, both mental and physical.

Alcohol can intensify what doctors call the positive symptoms of schizophrenia — things that are added, like hallucinations and delusions. It can also strengthen negative symptoms — things that are absent, like the absence of joy (anhedonia) or motivation (avolition).

Read on to learn more about the risks associated with drinking alcohol for people with schizophrenia.

Alcohol negatively affects the way our brains work and process information. Therefore, in cases of mental health disorders like schizophrenia, it’s generally not a good idea to drink alcohol.

According to the Centers for Disease Control and Prevention (CDC), excessive alcohol use includes:

  • Binge drinking. Consuming a high quantity of alcohol in a single 2- to 3-hour period. For women, this is four or more drinks, and for men it is five or more drinks.
  • Heavy drinking. High alcohol consumption per week. For women, this is eight or more drinks, and for men it is 15 or more drinks.
  • Underage drinking. Any alcohol consumption if you’re under 21 years of age.
  • Pregnant drinking. Any alcohol consumption by a pregnant person.

Sometimes people assume that those with schizophrenia use alcohol to self-medicate their symptoms from either schizophrenia itself or from the antipsychotic medications used to treat schizophrenia. But research has not supported this idea.

Some older, less commonly used antipsychotic medications might increase substance cravings and use.

There have been studies to examine the effects of antipsychotics on people with AUD, as well as the use of AUD medications for people with schizophrenia. One study suggested that long-acting injectable antipsychotic drugs may lead to better outcomes than daily oral medication, while another study suggested this was not the case. More investigation is needed.

People with schizophrenia are nearly three times more likely to develop SUD, including AUD, during their lifetime. In people with schizophrenia, SUD has been associated with:

  • increased severity of schizophrenia symptoms
  • non-compliance with treatment
  • violence
  • suicide
  • increased rates of re-hospitalization

One review found that nearly 1 in 4 people with schizophrenia also have AUD. Having dual diagnoses of both schizophrenia and AUD can lead to severe complications.

For people who have schizophrenia, the additional diagnosis of AUD increases the risk of other medical and social complications, including:

More broadly, studies show that alcohol use, when combined with mental illness, leads not only to an increase in physical aggression, but also an even greater increase in physical aggression victimization — especially for women.

Alcohol, when misused, has the potential to cause psychosis.

Psychosis is a collection of symptoms that can make it difficult to relate to reality. It’s considered a hallmark of schizophrenia. Symptoms of psychosis include:

When psychosis is a result of alcohol, it’s known as alcohol-related psychosis or alcohol hallucinosis. There are several forms of alcohol misuse that can lead to psychosis, including:

Although alcohol-related psychosis may appear similar to schizophrenia, it’s a distinct and separate condition. When compared to people with schizophrenia, people with alcohol-related psychosis are more likely to have:

  • less formal education
  • older age at first-episode psychosis
  • more intense depression
  • more intense anxiety
  • fewer disorganized thoughts and behaviors

Researchers haven’t determined the exact cause of alcohol-related psychosis. But it’s believed to be related to neurotransmitters that are affected by alcohol, such as dopamine and serotonin. Symptoms usually occur shortly after heavy drinking or during withdrawal.

If you’ve had alcohol-related psychosis, you’re less likely to have another episode if you abstain from alcohol.

Scientists haven’t proved that AUD causes schizophrenia, or that schizophrenia causes AUD. However, having one increases your likelihood of being diagnosed with the other.

People experiencing first-episode psychosis reported substance use between 30 and 70 percent of the time, and nearly 1 in 5 reported alcohol misuse.

This may point to schizophrenia and AUD sharing a common cause.

For example, researchers have suggested that alcohol use in adolescence is a predictor of having both a mental health disorder and SUD later in life.

Another theory suggests that the reward and motivation circuits in the brains of people with schizophrenia may be physiologically impaired, and that AUD shares the same impairment.

It’s believed that the risk of schizophrenia is strongly connected to genetics.

Twin studies have found that when one identical twin is diagnosed with schizophrenia, the second has a 41 to 65 percent chance of having the same diagnosis. For non-identical twins, the range drops dramatically, from 0 to 28 percent.

AUD may also have a genetic component, and studies have found a significant overlap between the genes related to AUD those related to schizophrenia.

Some signs that could indicate an alcohol or substance use problem include:

  • being unable to control how much they drink
  • frequent cravings for alcohol
  • continuing to drink despite negative effects
  • preferring to drink over other activites
  • have tried to quit drinking in the past but were unable to
  • spending a lot of time drinking or recovering from alcohol’s effects
  • having troubles with home, social, or work life because of alcohol
  • continuing to drink in risky situations
  • continuing to drink despite alcohol worsening their mood or memory
  • drinking more over time to feel the same effects
  • symptoms of withdrawal when not drinking, including:
    • nausea
    • sweating
    • shaking
    • vomiting
    • hallucinations

If you suspect someone with schizophrenia might be misusing alcohol, it’s important to remember that these signs are not definitive on their own, and if you’re going to approach them, to do so with empathy.

For people who have both AUD and a psychotic disorder such as schizophrenia, doctors recommend treating both disorders at the same time.

You can expect treatment to include medication and possibly some form of psychotherapy along with social interventions. Consult with a doctor to determine the right therapies for your particular circumstances.

Managing substance misuse and behavioral health must both be considered when coming up with a treatment plan. Your healthcare team might include:

  • psychiatrists
  • social workers
  • nurses
  • occupational therapists
  • peers

There are also 12-step programs available for people with both SUD and mental illness.

If you have schizophrenia and believe you also have AUD, reach out to a mental health professional or primary care physician. They may have treatment available, and if they don’t, they’re likely to be able to help you find treatment. Including a loved one in your treatment search can help you feel supported and stay motivated.