Which Drugs Trigger Schizophrenia? A Pharmacological Review

October 7, 2025 •

4 min read

Studies indicate that between 24% and 32% of individuals who experience drug-induced psychosis may later develop a schizophrenia spectrum disorder [1.3.2]. This article explores which drugs trigger schizophrenia-like symptoms and the difference between temporary psychosis and a chronic diagnosis.

Quick Summary

A variety of illicit drugs and prescription medications can induce psychosis, a state that mimics symptoms of schizophrenia. The risk depends on the substance, dosage, genetics, and other factors. Some episodes may unmask an underlying chronic disorder.

Key Points

Illicit and Rx Drugs: Both illegal substances like cannabis and stimulants, and prescription drugs like corticosteroids, can trigger psychosis [1.2.1, 1.4.1].
Psychosis vs. Schizophrenia: Drug-induced psychosis is often temporary, while schizophrenia is a chronic disorder; however, one can lead to the other [1.3.2, 1.3.6].
Cannabis Risk: Heavy cannabis use, especially starting in adolescence, significantly increases the risk of developing psychosis [1.2.1, 1.5.3].
Dopamine Disruption: Stimulants (cocaine, amphetamines) and Parkinson's medications trigger psychosis primarily by increasing dopamine activity [1.2.3, 1.9.1].
Glutamate & Serotonin: Dissociative drugs like ketamine (glutamate system) and hallucinogens like LSD (serotonin system) also produce schizophrenia-like symptoms [1.2.3].
Underlying Vulnerability: A personal or family history of mental illness and genetic predisposition are key risk factors for developing drug-induced psychosis [1.2.1, 1.2.5].
Medical Consultation is Key: Experiencing psychosis is a serious medical event that requires immediate evaluation by a healthcare professional [1.3.4, 1.6.2].

Understanding the Link Between Drugs and Psychosis

The relationship between substance use and schizophrenia is complex. While no drug is proven to cause schizophrenia outright, many substances can induce psychotic episodes characterized by hallucinations and delusions, the hallmark symptoms of the disorder [1.3.2, 1.3.4]. This condition is known as substance/medication-induced psychotic disorder [1.3.3]. For some vulnerable individuals, particularly those with a genetic predisposition, substance use can trigger the first episode of schizophrenia or worsen an existing condition [1.2.1, 1.2.2].

It is crucial to distinguish between substance-induced psychosis and schizophrenia. Substance-induced psychosis typically arises during or shortly after using a substance and often resolves once the drug clears from the system [1.3.4]. In contrast, schizophrenia is a chronic, lifelong mental health disorder where symptoms must persist for at least six months for a diagnosis, independent of substance use [1.3.2]. However, research shows a significant risk of converting from a drug-induced psychosis to a schizophrenia diagnosis, with some estimates as high as 46% for cannabis-induced psychosis [1.2.1].

Illicit Drugs Known to Trigger Psychosis

Several classes of illicit drugs are strongly associated with triggering psychotic episodes. Their mechanisms often involve disrupting key neurotransmitter systems in the brain, such as dopamine, serotonin, and glutamate [1.2.3].

Cannabis (Marijuana)

Cannabis is one of the most studied substances in relation to psychosis [1.2.3]. The risk is particularly linked to frequent use of high-potency cannabis, which is rich in delta-9-tetrahydrocannabinol (THC) [1.2.3]. Research indicates that regular cannabis users are twice as likely to develop psychosis, and heavy users are four times as likely [1.2.1]. The risk is highest for those who begin using cannabis during adolescence [1.2.1, 1.2.2]. THC can produce transient psychotic symptoms by stimulating CB1 receptors, which in turn can increase dopamine release in certain brain regions [1.2.3]. One study suggested that up to 30% of schizophrenia cases in young men might be prevented by avoiding cannabis use disorder [1.5.1].

Stimulants (Cocaine, Amphetamines, Methamphetamine)

This class of drugs is notorious for inducing psychosis, particularly paranoid delusions [1.6.1]. Stimulants like cocaine and amphetamines significantly increase the concentration of dopamine in the brain's synapses [1.2.3, 1.6.2]. This overstimulation of the dopamine system is central to the 'dopamine hypothesis of schizophrenia' and can produce symptoms nearly identical to paranoid schizophrenia [1.2.3]. Symptoms can include hallucinations (both auditory and visual), paranoia, and formication—the feeling of bugs crawling on or under the skin [1.2.1]. The risk is dose-dependent, and psychosis can become persistent in some chronic users [1.2.1, 1.6.1].

Hallucinogens and Dissociative Drugs

Classic Hallucinogens (LSD, Psilocybin): These drugs primarily act on the serotonin system, particularly the 5-HT2A receptors [1.2.3]. While they can produce profound perceptual distortions and hallucinations, the psychosis they induce is often characterized by more visual aberrations than is typical in schizophrenia [1.2.3].
Dissociative Drugs (PCP, Ketamine): Phencyclidine (PCP) and ketamine are known to cause short-term psychosis that closely mimics schizophrenia, including both positive and negative symptoms (like emotional flattening and cognitive impairment) [1.2.1, 1.2.3]. They act as NMDA receptor antagonists, which led to the 'glutamate hypothesis of schizophrenia' [1.2.3]. Ketamine, in particular, can cause hallucinations, delusions, and disorganized thinking that are temporary but can be severe [1.8.1, 1.8.5].

Prescription Medications That Can Induce Psychosis

Psychosis is not only linked to illicit substances but can also be a rare but serious side effect of various prescribed medications [1.4.1]. This is often dose-dependent and more likely in individuals with pre-existing risk factors [1.4.3].

Corticosteroids

Medications like prednisone, used to treat inflammation in conditions such as asthma and rheumatoid arthritis, can cause a range of psychiatric side effects, including psychosis [1.7.1]. 'Steroid psychosis' is more common with high doses (typically over 40 mg/day of prednisone equivalent) [1.7.1, 1.7.3]. The exact mechanism is unclear but is thought to involve the medication's impact on the HPA axis, as well as the dopamine and serotonin systems [1.7.1, 1.7.4].

Dopamine Agonists

Used primarily to treat Parkinson's disease, these drugs (e.g., levodopa, pramipexole, ropinirole) work by increasing dopamine levels or mimicking dopamine's effects in the brain [1.4.2]. While this helps manage motor symptoms, it can also lead to psychosis in up to 60% of patients, especially at higher doses [1.4.2, 1.9.1]. The resulting symptoms are often visual hallucinations [1.9.4].

Other Medications

Stimulants for ADHD: Medications like Adderall (amphetamine) and Ritalin (methylphenidate) can increase psychosis risk, especially at high doses [1.6.2, 1.6.4]. The risk appears to be higher for amphetamines compared to methylphenidate [1.6.5].
Antidepressants: Though rare, certain antidepressants, including SSRIs, SNRIs, and tricyclics, have been associated with inducing psychosis, particularly at high doses [1.4.2].
Miscellaneous Drugs: Other medications reported to have a risk of inducing psychosis include certain antibiotics, anticholinergics, and antiepileptic drugs [1.4.1, 1.4.3, 1.4.4].

Comparison of Psychosis-Inducing Drug Classes


Drug Class	Examples	Primary Mechanism of Action	Common Psychotic Features
Cannabinoids	Marijuana (THC)	CB1 receptor agonism, indirect dopamine increase [1.2.3]	Paranoia, perceptual alterations, conceptual disorganization [1.2.3].
Stimulants	Cocaine, Amphetamines	Block dopamine reuptake, increasing synaptic dopamine [1.2.3, 1.6.1]	Paranoid delusions, auditory/visual hallucinations, formication [1.2.1, 1.6.1].
Dissociatives	Ketamine, PCP	NMDA glutamate receptor antagonism [1.2.3]	Positive and negative symptoms similar to schizophrenia, dissociation [1.2.3, 1.8.1].
Corticosteroids	Prednisone, Dexamethasone	HPA axis disruption, dopamine/serotonin system effects [1.7.1, 1.7.4]	Mania, depression, hallucinations, delusions [1.7.1].
Dopamine Agonists	Levodopa, Ropinirole	Increase or mimic dopamine activity [1.4.2]	Primarily visual hallucinations, paranoid ideation [1.9.1, 1.9.4].

Conclusion

The link between drug use and schizophrenia-like psychosis is multifaceted. Illicit substances like cannabis and stimulants, along with prescription medications such as corticosteroids and dopamine agonists, can all precipitate psychotic episodes by disrupting the brain's delicate neurochemical balance [1.2.1, 1.4.2, 1.6.2]. While these episodes are often temporary, they can unmask or accelerate the onset of a chronic psychotic disorder like schizophrenia in vulnerable individuals [1.2.5]. Understanding these risks is vital for both users and clinicians to make informed decisions about substance use and medication management. If you or someone you know experiences psychotic symptoms, seeking immediate medical evaluation is critical.

For more information on substance use and mental health, visit the National Institute on Drug Abuse (NIDA).

Frequently Asked Questions

Drugs are not proven to directly cause schizophrenia, but they can trigger psychotic episodes that mimic its symptoms. In individuals who are already genetically vulnerable, substance use can precipitate the first episode of schizophrenia or worsen the condition [1.2.2, 1.3.4].

Symptoms of drug-induced psychosis typically last for a few hours to a few days and resolve once the substance has been eliminated from the body. However, in some cases, particularly with chronic use of drugs like methamphetamines, symptoms can persist for weeks or longer [1.2.1, 1.3.4].

Yes, research shows a strong link. Individuals who regularly use cannabis are twice as likely to develop psychosis, and those who use it heavily are four times more likely. The risk is especially high for adolescents and users of high-potency THC products [1.2.1].

The main differences are duration and cause. Drug-induced psychosis is directly tied to substance use or withdrawal and is often temporary. Schizophrenia is a chronic mental disorder with symptoms lasting at least six months, which cannot be solely attributed to substance use [1.3.2].

Anti-Parkinson drugs, which are dopaminergic, are associated with a very high risk, affecting up to 60% of patients [1.4.2]. High-dose corticosteroids also carry a significant risk [1.7.1]. Stimulants prescribed for ADHD, like amphetamines, are also a known risk factor [1.6.5].

While a single use of a powerful drug can trigger an acute psychotic episode, it is less likely to lead to a chronic schizophrenia diagnosis. More often, the transition from substance-induced psychosis to schizophrenia is associated with prolonged, heavy use of substances like cannabis or amphetamines [1.2.1, 1.2.3].

You should contact a healthcare professional immediately. Do not stop or change the dosage of your medication without medical supervision. A doctor can assess your symptoms, rule out other causes, and determine the safest course of action, which might involve adjusting the dosage or switching medications [1.7.1, 1.9.4].

Yes, major risk factors include a genetic predisposition or family history of mental illness, a previous psychiatric diagnosis, beginning substance use at a young age, and using high doses of a substance [1.2.1, 1.2.5].