Marijuana (Cannabinoids)Psychosis

Marijuana and the onset in psychotic disorders

 Early onset of psychosis is associated with a history of lifetime cannabis abuse or dependence, according to researchers at Harvard Medical School in Boston.

First, the details.

  • 233 patients with schizophrenia, schizoaffective disorder, or bipolar disorder with psychotic features were evaluated using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders.

And, the results.

  • The age at the onset of psychosis was 3 years earlier among those who used cannabis over a lifetime.
  • Patients developed cannabis abuse/dependence 3 years before psychosis.
  • There was no association with alcohol abuse/dependence.
  • Patients with lifetime panic disorder also had a 4-year earlier age at onset of psychosis.
  • The effects of panic disorder and cannabis abuse/dependence were independent of each another.

The bottom line?
The authors concluded, “Early onset of psychosis… is characterized by differential clinical features, notably a history of lifetime cannabis abuse/dependence.”

This is the latest in a series of studies published this year and summarized here.

12/9/08 20:49 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.