Rationale: Over 301 million people worldwide are suffering with anxiety disorders. Some of these use cannabis to help cope with their anxiety. Researchers are interested in knowing whether cannabis effectively treats anxiety.

Method: A large meta-analysis explored the link between anxiety and cannabis by combining results from 31 well-designed studies. 

Results: The analysis showed a positive association between anxiety and cannabis use: overall, people who used cannabis were about 1.24 times more likely to also be clinically anxious. Those with a cannabis use disorder were 1.68 times more likely to be anxious than non users. Even infrequent cannabis use was associated with more symptoms of anxiety.

Meaning: A large analysis of many studies suggests that anxiety disorders are not helped by cannabis, and may be worsened. Anxiety risk is elevated among those who have a cannabis use disorder, or even just use cannabis occasionally. If cannabis were good medicine for anxiety, we would expect symptoms to decrease with use, but this is not what the evidence shows.