High-potency cannabis may be associated with a higher risk of psychosis and cannabis use disorder compared with lower-potency products. The researchers who conducted a literature review on the question published their findings in Lancet Psychiatry.
Studies have shown that the Δ⁹-tetrahydrocannabinol (THC) concentration in cannabis has more than doubled over the past 10 years. Heavy cannabis use has been associated with a 4 times higher risk of psychosis. Use of the substance has also been linked to depression, anxiety and cannabis use disorder (CUD).
To explore the impact of higher-potency cannabis on mental health, the researchers searched Embase, PsycINFO, and MEDLINE for relevant studies published from inception through 2021. Out of 6389 possibilities, 20 studies met their criteria.
The studies indicated a higher risk of psychosis with high-potency cannabis compared with lower-potency products. A couple of the studies indicated users were up to 3 times more likely to develop psychosis symptoms for the first time. Another study that used an online survey found similar results. The association between anxiety and high-potency cannabis varied across studies.
The researchers stated they did not do a meta-analysis due to the limitations of their search. For example, some studies used self-reported data, and the studies presented inconsistent data on THC exposure.
The researchers suggested future research should explore the association in more detail. In the meantime, “the findings support recommendations to discourage the use of higher potency cannabis products for low-risk use,” the researchers concluded. “This recommendation should be incorporated into education tools and in the management of cannabis use in clinical settings. Policy makers should carefully consider cannabis potency when regulating cannabis in legal markets, such as through limits or taxes based on THC concentration.”
Petrilli K, Ofori S, Hines L, Taylor G, Adams S, Freeman TP. Association of cannabis potency with mental ill health and addiction: a systematic review. Lancet Psychiatry. 2022;S2215-0366(22)00161-4. doi:10.1016/S2215-0366(22)00161-4