Previous studies have found that cannabis users were more likely to develop psychotic disorders than non-cannabis users, but were unable to determine a causal relationship between use of the drug and psychosis. A new study suggests that there is no causal link.
In the new study, by comparing families with and without a history of marijuana use, the Harvard researchers were able to address this question.
They recruited four groups:
-87 non-psychotic people who had used no drugs.
-84 non-psychotic people who had used marijuana.
-32 patients who had schizophrenia but hadn’t used drugs.
-76 patients with schizophrenia who had used marijuana.
They then looked at the relatives of those with schizophrenia in comparison to the relatives of those in the control groups.
The results showed an increased risk of developing schizophrenia in the relatives of patients who already had schizophrenia, whether or not those patients used marijuana.
This study, then, finds no evidence that marijuana is associated with developing schizophrenia.
Full Story: PsyBlog: Marijuana Does Not Cause Schizophrenia
Mind blowing research that indicates that schizophrenia, bipolar disorder, and multiple sclerosis could be caused by a retrovirus and triggered by other infections such as toxoplasmosis:
The facts of schizophrenia are so peculiar, in fact, that they have led Torrey and a growing number of other scientists to abandon the traditional explanations of the disease and embrace a startling alternative. Schizophrenia, they say, does not begin as a psychological disease. Schizophrenia begins with an infection.
The idea has sparked skepticism, but after decades of hunting, Torrey and his colleagues think they have finally found the infectious agent. […]
After eight years of research, Perron finally completed his retrovirus’s gene sequence. What he found on that day in 1997 no one could have predicted; it instantly explained why so many others had failed before him. We imagine viruses as mariners, sailing from person to person across oceans of saliva, snot, or semen—but Perron’s bug was a homebody. It lives permanently in the human body at the very deepest level: inside our DNA. After years slaving away in a biohazard lab, Perron realized that everyone already carried the virus that causes multiple sclerosis. […]
Through this research, a rough account is emerging of how HERV-W could trigger diseases like schizophrenia, bipolar disorder, and MS. Although the body works hard to keep its ERVs under tight control, infections around the time of birth destabilize this tense standoff. Scribbled onto the marker board in Yolken’s office is a list of infections that are now known to awaken HERV-W—including herpes, toxoplasma, cytomegalovirus, and a dozen others. The HERV-W viruses that pour into the newborn’s blood and brain fluid during these infections contain proteins that may enrage the infant immune system. White blood cells vomit forth inflammatory molecules called cytokines, attracting more immune cells like riot police to a prison break. The scene turns toxic.
Previously: Virus Behind Insanity?
Photo by Micah Baldwin
A pair of authors suggest that the rise in mental illness since the 18th century is due to biological factors, possibly a virus: “Growing population and urbanization allowed the infectious agent — a virus or parasite — to spread more rapidly in the densely populated cities, they say.” Or it could just be increased diagnosis, rather than increased occurrence.
(via Post Atomic)
See also: Is Schizophrenia Caused by Retroviruses?