After reviewing existing literature and statistics, researchers from the University of Warwick have found evidence which suggests a significant relationship between cannabis consumption and the onset (or exacerbation) of mania symptoms.

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We’ve presented quite a few studies on cannabis here on ZME Science. Our general impression is that due to legal constraints (which are somewhat debatable), the medical potential of the substance is largely ignored. In 2014, a study showed that inhaled cannabis can significantly mitigate Parkinsons symptoms, and another one also shown some promise in easing pain and fighting depression. However, it’s not all good; heavy consumption leads to poor memory and abnormal brain structure and teen consumption also has negative impacts on the brain.  Now, in a paper published in the Journal of Affective Disorders, mental health researchers found another negative side effect: cannabis causes or accentuates mania symptoms.

Technically speaking, mania is the mood of an abnormally elevated arousal energy level; manic depression is also called bipolar disorder. High irritability, depression and overall frenzy are all symptoms of mania, which can itself be a symptom of other psychological conditions. During a manic phase, patients tend to feel euphoric and may believe they can accomplish anything – but this usually backfires, and the exactly opposite feelings set in.

The fact that marijuana consumption seems to be connected to mania is, while interesting, not entirely surprising. Lead author Dr Steven Marwaha said:

“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?”

After analyzing previous studies and medical statistics, they found the answer to those questions.

“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.”

In other words, we now know that cannabis consumption and mania are linked; it doesn’t necessarily means that one causes another, but that’s definitely possible. The research also showed that in people already suffering from mania, the symptoms are greatly exacerbated.

Scientists also underlined the fact that the clinical use of cannabis is grossly understudied.

“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 effected by genetic vulnerability and environmental risk factors.”

Journal Reference:

1. Melanie Gibbs, Catherine Winsper, Steven Marwaha, Eleanor Gilbert, Matthew Broome, Swaran P. Singh. Cannabis use and mania symptoms: A systematic review and meta-analysis. Journal of Affective Disorders, 2015; 171: 39 DOI:10.1016/j.jad.2014.09.016