Can Alcohol or Marijuana Cause Psychosis?


We know that alcohol can damage the brain, disrupt sleep, and lead to addiction. Cannabis, too, can create dependence, while inhibiting blood flow to the brain and impairing short- and long-term memory. But both of these popular drugs have additional serious side effects that you might not have heard about—including the risk of delusions, hallucinations, and psychosis.

According to the National Alliance on Mental Illness (NAMI), psychosis describes “a break with reality,” and 3 in 100 people may experience an episode at some point in their lives, with about 100,000 young people affected every year. Psychosis itself is a symptom, not an illness, and may include delusions and hallucinations—two types of responses that may occur as a result of psychotic disorders.

Alcohol and marijuana both have additional serious side effects that you might not have heard about—including the risk of delusions, hallucinations, and psychosis. Click To Tweet

One point to note, according to American Addiction Centers, is that while hallucinogenic drugs may cause users to see, hear, or feel things that aren’t there, these side effects are not the same as psychosis (though having an adverse reaction to, or taking too much of, these types of drugs can lead to disturbing symptoms like delusions and paranoia). Findings from a study in Experimental Neurobiology show that substances like PCP and LSD are known for causing short-term or long-term effects on the experience of reality, but drugs considered “less harmful” and often legalized (such as alcohol and marijuana) are also associated with psychosis—either while on the drug, or when attempting to stop taking it after prolonged use.


NAMI notes that psychosis, overall, is “characterized as disruptions to a person’s thoughts and perceptions that make it difficult for them to recognize what is real and what isn’t.” One manifestation of this kind of skewed experience among drug users is having delusions, which involves clinging to beliefs that have no basis in reality. For example, a person may believe that the federal government has installed surveillance to spy on them, even though no evidence of this exists. Hallucinations, on the other hand, involve seeing or hearing things that aren’t there or having unusual bodily sensations, such as the feeling that bugs are crawling on the skin.

Other psychotic symptoms include disorganized thinking and incoherent speech; abnormal or disorganized movements, including catatonia, or lack of movement; diminished emotional expression; and “negative symptoms” (lack of engagement in activities, speaking, socializing, etc.). In general, psychotic symptoms can range from mild to severe, causing levels of impairment that can affect an individual’s ability to function, leading them to struggle with basic tasks like maintaining interpersonal relationships, attending work or school, and keeping up with basic self-care.


Substance-induced psychotic disorder is the term used for a person experiencing any of the above symptoms as a result of taking or withdrawing from a drug (and, as a reminder, alcohol is a drug that can damage the brain). Cannabis-induced psychosis seems to occur even more commonly today, as new and stronger strains of the drug circulate, and as legalization efforts increase their usage and acceptance. Research shows that marijuana increases the risk for psychosis, and the findings of a 2019 study published in The Lancet Psychiatry suggest that 10% of new cases of psychosis may be linked to high-potency cannabis. The study also found that daily users of high-potency strains were 5 times more likely to develop a psychotic disorder. Other research has shown that using marijuana at an early age, such as during the teen or tween years, is associated with an increased risk of psychosis.

A 2021 medical review noted that psychosis due to substance abuse is now a common issue observed in medical settings, and the likelihood of developing psychosis “seems to be associated with the severity of use and dependence.” Additionally, with new substances now frequently emerging, it can be difficult to track everything that is available through illicit markets, along with fully studying their long-term effects. “The variety of substances able to provoke an episode of acute psychosis is rapidly increasing,” the report stated.

Alcohol, on the other hand, is more often associated with hallucinations in someone who has abused alcohol for a time and/or has ingested heavier quantities—often when they are trying to quit. This is called alcoholic hallucinosis, and it’s an alarming side effect of chronic alcohol abuse. Research has noted this issue usually involves “acoustic verbal hallucinations, delusions, and mood disturbances arising in clear consciousness and sometimes may progress to a chronic form, mimicking schizophrenia.” Another term for this issue is alcohol-related psychosis, and substance abuse researchers explain that it can also occur as a result of acute intoxication after an episode of heavy intake—creating symptoms like hallucinations, paranoia, and fear.


American Addiction Centers notes that using substances like marijuana can increase the risk of psychosis among those who are already vulnerable based on other factors. These factors include:


The nature of psychotic disorders—such as ongoing thought disturbances and the failure to accurately perceive reality—means that they are considered among the most challenging psychiatric conditions to address. Treatment is possible and may include psychotherapy, medication, lifestyle changes, and other methods of management, so someone who suffers from psychotic conditions can take steps to manage symptoms.

Still, especially if there are pre-existing vulnerabilities, it’s best to avoid the chances of these episodes occurring to begin with. Steer clear of dangerous and addictive substances like marijuana and alcohol, which can lead to the frightening, reality-twisting symptoms of psychosis. Unfortunately, most people with addictions or dependencies on drugs like marijuana and alcohol do not receive treatment, such as entering residential programs. But if you or someone you love is affected by addiction, be proactive and seek help, not only for the addiction but also for the underlying factors that contribute to the problem. It is crucial to address these issues before they lead to the possible lasting damage associated with psychosis.

Psychotic symptoms, addiction, and other mental health issues can’t wait. At Amen Clinics, we’re here for you. We offer in-clinic brain scanning and appointments, as well as mental telehealth, remote clinical evaluations, and video therapy for adults, children, and couples. Find out more by speaking to a specialist today at 888-288-9834 or visit our contact page here.


  1. Always appreciate the researched information and your perspective on mental wellness!

    Comment by Rich Campbell — September 26, 2022 @ 1:17 PM

  2. I very much Appreciate the information contained in your article, especially about the effects of long term usage of the combination of the two drugs.

    Comment by Darryl Sanford — October 4, 2022 @ 1:10 AM

  3. This is a great information!

    Comment by Douglas Morris — August 4, 2023 @ 6:56 PM

RSS feed for comments on this post.

Leave a comment

Contact Us