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Significant Link Between Cannabis Use and Mania Symptoms


There is a strong link between smoking cannabis and the exacerbation of mania symptoms, including feelings of anger, hyperactivity and delusions, report reveals.

Mental health researchers from Warwick Medical School carried out a review of scientific reports which examined the effects of cannabis use. The paper, published in the Journal of Affective Disorders, sampled 2,391 individuals who had experienced mania symptoms.

Mania symptoms are part of bipolar disorder and patients may experience symptoms including extreme elation, a reduced need for sleep, aggressive behavior and hearing voices. Lots of symptoms that a cannabis user may also experience after extended use of the drug.

"Previously it has been unclear whether cannabis use predates manic episodes. We wanted to answer two questions – does cannabis use lead to increased occurrence of mania symptoms or manic episodes in individuals with pre-existing bipolar disorder? But also, does cannabis use increase the risk of onset of mania symptoms in those without pre-existing bipolar disorder?" said Dr Steven Marwaha, the lead author of the report.

"Cannabis is the most prevalent drug used by the under-18s and during this critical period of development services should be especially aware of and responsive to the problems that cannabis use can cause for adolescent populations’ he continued.

The original scientific report was conducted by researchers, led by Melissa DelBello, MD, the Dr. Stanley and Mickey Kaplan Chair of Psychiatry and Behavioral Neuroscience.

The researchers studied 103 adolescents between 12 and 20 years who had been diagnosed with bipolar and hospitalised. Out of 103 adolescent 32 had already been diagnosed with a substance abuse disorder. 17 participants were diagnosed with alcohol abuse or dependency and 12 for cannabis, the other 3 participants were involved in using both alcohol and cannabis.

The remaining 71 participants developed a substance use disorder during their follow up period, around 17-283 weeks.

"Our analyses revealed several risk factors that were associated with developing a new substance use disorder after the first manic episode in adolescence," said DelBello at the time the report was published. "Psychosis and PTSD showed the strongest evidence of predicting a new-onset substance use disorder."

Researchers at Warwick Medical School looked at previous reports and studies to conclude that cannabis use paved the way for the onset of mania symptoms.

"The observed tendency for cannabis use 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" said Dr Marwaha.

"There are limited studies addressing the association of cannabis use and manic symptoms, which suggests this is a relatively neglected clinical issue. However our review suggests that cannabis use is a major clinical problem occurring early in the evolving course of bipolar disorder. More research is needed to consider specific pathways from cannabis use to mania and how these may be affected by genetic vulnerability and environmental risk factors” He added.


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