‘Significant’ link between cannabis and mania – study

Reuters/Alessandro Bianchi
There is a ‘significant’ link between the onset and exacerbation of mania symptoms and cannabis use, claims a study by a leading institution.

Researchers from the University of Warwick say cannabis can be linked to mania – symptoms of which include prolonged states of elatedness, difficulty in sleeping and hyperactivity, and bouts of aggression, and in extreme cases becoming delusional or hearing voices.

Dr Steven Marwaha, author of the study published in the Journal of Affective Disorders, said: “Previously it has been unclear whether cannabis use predates manic episodes.”

He said the researchers tried to determine whether cannabis use can lead to an increase in mania symptoms or manic episodes in both individuals with pre-existing and those without pre-existing bipolar disorder. They examined 2,391 people who had experienced mania symptoms.

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“The observed tendency for cannabis use is to precede or coincide with, rather than follow, mania symptoms, and the more specific association between cannabis use and new onset manic symptoms, suggests potential causal influences from cannabis use to the development of mania. It is a significant link,” he said.

“Our review suggests that cannabis use is a major clinical problem occurring early in the evolving course of bipolar disorder.”

He added that the findings suggest cannabis use significantly worsened mania symptoms in people who had previously been diagnosed with bipolar disorder.

Cannabis is the most prevalent drug used by the under-18s, where brain development is at a critical stage. Marwaha claims the use of cannabis could lead to manic episodes later in life.

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Meanwhile, a study released earlier this month said cannabis has the potential be used to treat depression caused by chronic stress.

The team, from the University at Buffalo's Research Institute on Addictions in New York, examined endocannabinoids, which are chemicals in the brain similar to substances found in cannabis.

Senior researcher Samir Haj-Dahmane said: “Chronic stress is one of the major causes of depression. Using compounds derived from cannabis — marijuana — to restore normal endocannabinoid function could potentially help stabilize moods and ease depression.”

Medical marijuana is legal in 23 US states, where it can be used for conditions like multiple sclerosis and glaucoma.