New research suggests that the effect of cannabis on dopamine may help to treat certain symptoms of bipolar disorder.

Researchers from the University of California San Diego recently presented findings that cannabis use may help modulate overactive dopaminergic activity in bipolar patients whose symptoms are thought to arise in part from increased dopamine – a neurotransmitter which plays an important role, when at normal levels, in motivation, the sense of wellbeing and other key human behaviours.

Specifically the researchers found that bipolar patients who were also cannabis users showed a reduced tendency to engage in risky behaviours, as well as normalised motivation and some improvement in cognitive ability.

The improvements only held true for the bipolar participants, and not for the general population, leading the authors to infer that dopaminergic modulation may be responsible for the outcomes.

This differs from previous research that reported negative implications of cannabis and dopamine – for example evidence suggesting that chronic use of cannabis was linked to reduced striatal dopamine release.


A complex relationship

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    The relationship between cannabis and dopaminergic function is complex. THC indirectly causes an increase in dopamine levels during and after cannabis use. Although it’s not fully understood, sustained exposure to elevated levels of dopamine prompts adaptations in the brain that lead to reduced dopaminergic function in otherwise healthy individuals.

    These changes can lead to issues such as poor memory, decreased focus, impaired learning ability, increased impulsiveness and a poor sense of wellbeing relative to abstinence or mild use. In addition, this effect on dopamine is believed to play a part in the habit-forming or addictive properties of long-term cannabis use.

    However, for those with already elevated dopaminergic activity this new research presented at a conference hosted by the Society for Neuroscience suggests cannabis use may be a different story entirely.

    More research is needed in a larger sample to confirm and elaborate on these results, but the findings provide promise of yet another potential application of cannabis in the medical space. Other health conditions such as obesity and schizophrenia have been linked to elevated dopamine, offering up other diseases that may also benefit from these findings.

    These results highlight the complexity of cannabis as a substance whose properties can vary across populations. With any cannabis research one should keep in mind that what is bad news for some may turn out to be good news for others.

    Clayton Hale CannIntelligence contributing writer

    Photo: Carole Raddato

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    This article was written by one of CannIntelligence’s international correspondents. We currently employ more than 40 reporters around the world to cover individual cannabis and cannabinoid markets. For a full list, please see our Who We Are page.