While many students believe that marijuana is exclusively a recreational drug with no harmful effects, studies are beginning to show that this may not be the case. According to a recent study, there is a distinct correlation between marijuana use and the onset of schizophrenia-spectrum disorder.

Getting high from marijuana usually results in a relaxed feeling, but for some, it can end in a marijuana-induced psychosis.

The study, performed in Denmark by Dr. Mikkel Arendt, found that of the latter group, 77 percent of patients develop subsequent psychotic episodes and 45 percent are diagnosed with a schizophrenia-spectrum disorder.

“For the majority of patients, cannabis-induced psychotic symptoms proved to be a first step in the development of a schizophrenia-spectrum disorder or other severe psychopathology,” Arendt wrote in the British Journal of Psychiatry.

Not only is there a strong correlation between cannabis-induced psychosis and schizophrenia, but it also hastens the onset of schizophrenic symptoms.

Marijuana usage cannot be causally linked with schizophrenia diagnosis by this study because there are too many outside factors to be considered, including genetic predisposition, socioeconomic status and the use of other drugs. However, Eric Strain, a psychology professor at Johns Hopkins University, said that the study has significant findings, regardless of its lack of a definitive conclusion.

“The study suggests that a substance-induced psychotic episode serves as an important indicator identifying a group of patients at high risk for subsequent psychiatric needs,” Strain said in a Psychiatric News article.

In an article for Nature Reviews, Robin M. Murray said that the strongest correlation between marijuana-induced psychosis is in individuals who already have a predisposition for psychotic disorders.

“Individuals without evidence of any predisposition to psychosis generally responded to cannabis by feeling more at ease with the world, and experienced only minor perceptual change,” Murray wrote. “However, those who were identified as psychosis-prone reported more marked perceptual changes, and feelings of increased suspicion and hostility after taking cannabis.”

Murray’s article goes on to say that the use of marijuana by an individual who is psychosis-prone increases his or her risk for psychotic symptoms by 24 percent while the risk for non-predisposed users is only increased by 6 percent.

Murray cites a Swedish study of 50,000 men that found that “men who had smoked cannabis by the age of conscription had doubled the risk of schizophrenia in the ensuing 15 years. In addition, they found that men who had smoked cannabis on at least 50 occasions were six times more likely to later receive a diagnosis of schizophrenia.”

Brad Baumes, a junior cinema major, on the other hand, pointed out that there is a significant lack of causality to these studies.

“As far as I know marijuana use only brings out emotional problems that you already have. It doesn’t cause the problems,” Baumes said. “I know a lot of people who use marijuana and I don’t know anyone who has had marijuana-induced psychosis, at least on the psychotic level.”

Another study in New Zealand shows results similar to those of the other studies mentioned.

“Those who had used cannabis by the ages of 15 or 18 reported significantly more psychotic symptoms at age 26 compared with non-users,” Murray wrote. “Furthermore, 10 percent of those who used cannabis by the age of 15 was diagnosed with schizophrenia psychosis when they were 26 years old, compared with 3 percent of the non-using control group.”

However, Baumes pointed out that there may be other factors involved.

“The people that choose to smoke marijuana and also get diagnosed with schizophrenia may also happen to be a group of people that also do something else. There are too many factors to say that marijuana causes schizophrenia,” Baumes said.

Baumes makes a valid point, as much as the criticism of the correlation between marijuana and psychopathology is that there are in fact far too many confounding variables.

While many of the findings of these studies cannot conclusively link marijuana use to the manifestation of schizophrenia-spectrum disorders, even the smallest correlation could mean that it will affect a large number of people.

As Murray states, marijuana is the third most popular recreational drug following alcohol and tobacco — meaning that even the smallest percentage of users that may develop schizophrenia because of their marijuana usage will result in a large number of new cases of the disorder.

Meagan Jean, a junior philosophy, politics and law major, said that she was not aware of the correlation.

“After a certain amount of time using marijuana I could see why some type of mental disorder could result,” Jean said. “Basically, whenever you are messing around with your brain by using drugs there could always be consequences. I never thought that there was that strong of a correlation, though, especially with schizophrenia.”

Ryan Dean, a pre-med junior, said that the study won’t have an effect on whether or not this study will change college students’ minds about smoking.

“Smoking marijuana with the information that it could lead to schizophrenia is like drunk driving,” Dean said. “You know the risks, but they don’t seem to outweigh the experience or convenience of doing either one.”