How Does Drug Use Cause Schizophrenia?

Medically Reviewed on 5/3/2022

Which drugs can cause schizophrenia?

Schizophrenia is one of the most common mental illnesses. Although drug use does not cause schizophrenia, there is unassailable evidence that the two are closely related.
Schizophrenia is one of the most common mental illnesses. Although drug use does not cause schizophrenia, there is unassailable evidence that the two are closely related.

Schizophrenia is one of the most common mental illnesses. It causes you to lose touch with reality, affecting your ability to distinguish between what’s real and what’s not. 

While it is unclear to many what causes this condition, some people appear to be born susceptible. For example, men are more likely to develop schizophrenia than women, and some people are genetically predisposed. 

According to scientific data, drugs do not directly cause schizophrenia. However, there is more than enough compelling evidence that drug misuse can increase the risk of developing schizophrenia or a similar illness. 

You may be wondering whether drug use causes schizophrenia. Simply put, you may already have this condition, but symptoms are mild until you have a drug-induced break. In this case, one may assume that your condition was caused by the drug now that the signs are clear. 

You may also experience a drug-induced psychotic break that progresses to schizophrenia. While it may make some sense to say that the drugs were responsible, sometimes it’s just the case that you were prone to develop schizophrenia in the first place.

Some drugs, like cocaine, LSD, or amphetamines, can bring about symptoms of schizophrenia in individuals who are susceptible. These drugs can also lead to psychosis or cause a relapse in someone who’s already recovering from an episode. 

Teenagers and young adults who often use cannabis are more likely to develop schizophrenia later in life.

Some of the symptoms of schizophrenia can also be mistaken for signs of drug addiction. These include things like:

  • Hallucinations
  • Being delirious or believing things that are not true
  • Lack of motivation
  • Trouble organizing your thoughts
  • Social isolation
  • Difficulty speaking clearly

The link between schizophrenia and drug use comes down to the human brain. Past research has documented relationships between dopamine, serotonin, drug use, and mental illness

Dopamine and schizophrenia

Experts have developed the dopamine theory of schizophrenia, also referred to as the “dopamine hypothesis.” It states that overproduction of dopamine may result in schizophrenic symptoms. The signs of schizophrenia and being high on drugs can be traced back to increased levels of dopamine. 

Dopamine causes a disruption in your working memory. Perhaps it’s the reason why people think that certain schizophrenic individuals must be abusing drugs, which is a wrong assumption to make.

Serotonin and schizophrenia

Changes in serotonin levels are also closely linked to schizophrenia. Fluctuations in levels of serotonin can lead to symptoms that can be mistaken for mental illness: for example, disruptions of certain cognitive processes, attention span, sensitivity to pain, aggression, mood, sleep, sexual drive, appetite, and energy levels. 

Prescription drugs and schizophrenia

Certain prescription medicines also play a role in the link between drugs and schizophrenia. 

Clozapine. This antipsychotic medicine works by rebalancing serotonin and dopamine to improve thinking, mood, and behavior. It also has known effects on the reduction of suicidal ideation in people diagnosed with schizophrenia and other similar disorders. Once you start taking clozapine for schizophrenia, it is not advisable to miss a dose, as it may increase the likelihood of a relapse.

Amphetamines. This class of drugs acts as stimulants to the central nervous system. Common examples of amphetamines are Adderall, methamphetamine, and ecstasy. The use of these drugs results in an increase in certain types of brain activity. People abuse amphetamines to feel more energetic, confident, and euphoric. They also cause a reduction of the apathy often associated with schizophrenia. 

Despite the feeling of being focused and energetic that amphetamines give, scientific evidence shows that people who use amphetamines are worse at performing duties than non-users. 


Schizophrenia is the most disabling mental illness. See Answer

Cannabis and schizophrenia

Cannabis does not cause schizophrenia or psychosis. However, people with schizophrenia are more likely to misuse the drug than other people. These effects are more pronounced in younger people and individuals with first-episode psychosis. According to some studies, increasing the frequency and dose of cannabis may predict the onset of schizophrenia or psychosis in the future.

People who start using cannabis at a younger age double the risk of developing schizophrenia in the future. The same applies to daily use of high-potency cannabis, which particularly increases the chance of future mental illness by as much as five times. 

The culprit is tetrahydrocannabinol (THC), which is the psychoactive substance responsible for the high associated with marijuana use. The effects of THC in nonpsychotic persons are the same as the positive, negative, and cognitive symptoms of schizophrenia. They also mimic the neurophysiological occurrences synonymous with psychosis.

Cocaine and schizophrenia

It is possible that cocaine can lead to the progression of schizophrenia. There are cases where individuals diagnosed with the condition report having used cocaine within a year preceding the onset of symptoms. 

Cocaine is known to cause a dysfunction of the prefrontal cortex of the brain. This is one of the neurological signs of schizophrenia. Also, this drug can worsen the paranoia and hallucinations associated with schizophrenia.


Although drug use does not cause schizophrenia, there is unassailable evidence that the two are closely related. Some of the chemical changes that drugs cause in your brain can be responsible for the progression of psychosis. 

It’s therefore important that individuals who present with symptoms of related mental illnesses be discouraged from drug use. There is also a pressing need for educating children and adolescents about recreational drug use, as they may otherwise end up dealing with serious mental issues in later adulthood due to the effect of drug use on brain development. 

Ultimately, though, drug addiction and schizophrenia are two different conditions that should be addressed and treated separately.

Medically Reviewed on 5/3/2022

American Addiction Centers: "Amphetamine Addiction: Symptoms, Side Effects & Treatment."

American College of Neuropsychopharmacology: "The Role of Serotonin in Schizophrenia."


Cochrane: "Amphetamines for schizophrenia."

Cureus Journal of Medical Science: "The Association Between Cannabis Use and Schizophrenia: Causative or Curative? A Systematic Review."

Frontiers in Psychiatry: "The role of dopamine in schizophrenia from a neurobiological and evolutionary perspective: old fashioned, but still in vogue."

Georgetown Behavioral Hospital: "Drug-Induced Schizophrenia: Triggers, Causes, & Treatments."

National Alliance on Mental Illness: "Clozapine (Clozaril and FazaClo)."

National Health Service: "Causes - Schizophrenia."

Neuropsychopharmacology: "An experimental study of catechol-o-methyltransferase Val158Met moderation of delta-9-tetrahydrocannabinol-induced effects on psychosis and cognition."

Neuroscience: "Dopaminergic control of working memory and its relevance to schizophrenia: A circuit dynamics perspective."

Schizophrenia Research: "Marijuana Use in the Immediate 5-Year Premorbid Period is Associated with Increased Risk of Onset of Schizophrenia and Related Psychotic Disorders."