Can THC Help Some Schizophrenics?

Jun 04, 2009

cannabinoids, marijuana, schizophrenia, THC

The surprising finding that THC might help at least a small percentage of schizophrenia patients for whom conventional treatments have failed was reported in the June issue of the Journal of Clinical Psychopharmacology

This is surprising because, as the British government's Advisory Council on the Misuse of Drugs reported last year, "there is clear evidence that the use of cannabis may worsen the symptoms of schizophrenia and lead to relapse." The ACMD -- a far more objective body than any U.S. government outfit remotely connected to drug policy -- did not consider marijuana to be a significant cause of psychosis in otherwise healthy people; its report reflects a broad consensus that marijuana (and specifically THC) can worsen the prognosis of schizophrenics or those with a genetic vulnerability to schizophrenia.

But doctors at the Rockland Psychiatric Center in Orangeburg, New York, reviewing the records of one severely ill patient -- a man who was "grossly psychotic, assaultive, disorganized" and not responding to conventional treatment -- noticed that he had a history of "calm behavior when he was using marijuana." So as an experiment, they prescribed THC capsules (dronabinol, brand name Marinol). "Remarkably," they write, "he became calm, logical, nonviolent, and cooperative within days and was discharged within weeks." 

They then tried the same thing with five other patients with a similar history -- unresponsive to conventional treatments but showing some signs of improvement when they smoked marijuana. Three of these "improved to a clinically significant extent," one showed no significant change, and one got somewhat worse. That's a remarkable level of success in chronically ill patients for whom conventional antipsychotic drugs had failed, "in which success with any intervention might be unlikely."

The article goes on to lay out some possible explanations, but at this point no one knows for sure why this small group of psychotic patients had an anomalous and positive reaction to THC. What is clear is that the relationship of cannabinoids to schizophrenia is more complex and variable than even many experts -- much less anti-marijuana propagandists -- have acknowledged.