Addiction Research

Daily Marijuana Use Can Lead to Early Onset of Psychosis

Daily marijuana use can lead to more than just a mellow disposition. According to a new Emory University study, such use in adolescence may hasten the onset of symptoms leading up to psychosis.

This study was summarized in a Science Daily release and was recently published in the November issue of the American Journal of Psychiatry.

To reach their findings, researchers analyzed data from 109 hospitalized patients who were experiencing their first psychotic episode. The results from this analysis showed that patients who had a history of using marijuana or cannabis and increased to daily pot smoking experienced both psychotic and pre-psychotic symptoms at earlier stages.

"We were surprised that it wasn’t just whether or not they used cannabis in adolescence that predicted the age of onset, rather it was how quickly they progressed to becoming a daily cannabis user that was the stronger predictor," said Michael Compton, lead author and assistant professor of psychiatry in the Emory School of Medicine.

There was also a gender difference identified in the study. Female subjects who progressed to daily pot smoking had a greater increased risk for the onset of psychosis than males.

For those individuals suffering with schizophrenia, the most abused illicit substance is marijuana. Previous research into this area has shown that pot smoking is likely a risk factor for the disease.

The Emory study also examined what is known as the prodromal period – the period of time when a person has symptoms such as unusual sensory experiences, often precursors to frank hallucinations and delusions.

Prodromal symptoms have been known to occur months, or years, before a diagnosis of psychosis. Roughly 30 to 40 percent of prodomal teenagers will eventually develop schizophrenia or another psychotic disorder.

Elaine Walker, a co-investigator of the study and professor of psychology and neuroscience at Emory noted, "The prodromal period is especially important because it’s considered to be a critical time for preventive intervention.”