NEW YORK, United States, Tuesday February 10, 2015 – A controversial new study, which challenges previous research linking marijuana to increased rates of mental illness, has suggested that the herb could be used to treat depression that results from long term stress.
Scientists found that chronic stress reduced the production of endocannabinoids – naturally produced chemical compounds in the brain that affect motor control, cognition, emotions and behaviour – leading to depression.
Endocannabinoids are nevertheless similar to the chemicals found in marijuana (cannabis) and its active ingredient, delta-9-tetrahydrocannabinol (THC), which could be used to restore endocannabinoids levels in the brain, according to researchers at the University of Buffalo.
“Chronic stress is one of the major causes of depression,” said Dr Samir Haj-Dahmane of the University’s Research Institute on Addictions.
“Using compounds derived from cannabis to restore normal endocannabinoid function could potentially help stabilise moods and ease depression.”
The study, which was published in the journal Neuroscience, did not indicate which form of marijuana would best treat stress-related depression.
Dr Haj-Dahmane also pointed out that the research is at a very early stage.
“Our research thus far has used animal models; there is still a long way to go before we know whether this can be effective in humans,” he said.
“However, we have seen that some people who suffer from post-traumatic stress disorder have reported relief using marijuana.”
Dr Haj-Dahmane added that the next step in the research is to determine whether using a marijuana extract, cannabidiol (CBD), restores normal behaviours in the animals without leading to dependence on the drug.
Previous studies have nonetheless found that smoking marijuana increases the risk of depression, anxiety, psychosis and schizophrenia.
Last October, a definitive 20-year study into the effects of long-term marijuana use concluded that it is addictive, causes mental health problems and opens the door to hard drugs.
The paper by Professor Wayne Hall, a drugs advisor to the World Health Organisation (WHO), found smoking marijuana doubles the risk of developing psychotic disorders.
Professor Hall’s findings also indicated that one-in-six teenagers who regularly smoked the drug became dependent on it, and cannabis users did worse at school.
Meanwhile, US researchers found the brains of users were less able to react to dopamine, the “feel-good” chemical that prompts the feeling of “get-up-and-go.”