Could Marijuana Use Increase the Risk of Depression?

As more states push for medical and recreational use of marijuana, a new study shows that regular use of the drug can increase the risk of depression and anxiety in some individuals.

Findings published in the journal the Proceedings of the National Academy of Sciences (PNAS) found that people who use marijuana typically have brains that are less capable of responding to dopamine, a neurotransmitter that triggers motivation for rewards.

Furthermore, the latest study results also reiterate previous findings that suggest that marijuana use can leave people feeling lazy and indifferent about life in general.

For this study in particular, researchers examined 48 people who used Ritalin. According to researchers, this ADHD drug was used to help them better understand how marijuana influences the brain via dopamine levels.

Findings revealed that marijuana users had significantly lower dopamine levels than healthy controls--all which signaled signs of marijuana addiction that could lead to increased rates of depression and anxiety.

"We found that marijuana abusers display attenuated dopamine (DA) responses to MP, including reduced decreases in striatal distribution volumes. These deficits cannot be unambiguously ascribed to reduced DA release (because decreases in nondisplaceable binding potential were not blunted) but could reflect a downstream postsynaptic effect that in the ventral striatum (brain reward region) might contribute to marijuana's negative emotionality and addictive behaviors," researchers added, in a news release. 

"Moves to legalize marijuana highlight the urgency to investigate effects of chronic marijuana in the human brain."