From Psych Central (December 13, 2013) — “New research from Harvard Medical School, in a comparison between families with a history of schizophrenia and those without, finds little support for marijuana use as a cause of schizophrenia.”
Link to article:
In this first-of-its-kind study by researchers at Harvard University, this long-debated question seems to have been answered. And the naysayers are right.
This study used four experimental groups:
- Group #1 — Controls with no lifetime history of psychotic illness, cannabis, or any other drug use.
- Group #2 — Controls with no lifetime history of psychotic illness, and a history of heavy cannabis use during adolescence, but no other drug use.
- Group #3 — Patients with no lifetime history of cannabis use or any other drug and less than 10 years of being ill.
- Group #4 — Patients with a history of heavy cannabis use and no other drug use during adolescence and prior to the onset of psychosis.
A total of 282 people served as direct participants in this study with another 4,291 relatives of the test subjects used to gather family histories. Here is the verdict:
“The researchers concluded that the results of the current study…suggest that having an increased familial risk for schizophrenia is the underlying basis for schizophrenia in these samples — not the cannabis use.”
In science however one study — regardless of how extensive — usually doesn’t cut it. As a lifelong naysayer concerning this topic, I am hopeful that these findings will be replicated by future research. Common sense doesn’t always prevail. Sometimes, common sense is dead wrong. However, this is one instance (in my opinion) where common sense prevails. The idea that cannabis causes schizophrenia has always seemed a bit preposterous to me.
If you are so inclined, I am adding a link to the full text of the research article published in the journal, Schizophrenia Research. Here is the link: