Ann Intern Med

High-potency cannabis tied to psychosis and addiction risk

August 27, 2025

Study details: This systematic review analyzed 99 studies involving >221,000 individuals from 1977 to 2023. Researchers examined associations between high-concentration delta-9-tetrahydrocannabinol (THC) cannabis products (defined as >5 mg or >10% THC/serving or labeled as “shatter,” “dab,” or “high-potency concentrate”) and mental health outcomes. Studies included randomized trials, observational studies, and therapeutic investigations.

Results: Among non-therapeutic studies, high-THC products were consistently associated with increased risk of psychosis or schizophrenia (70%) and cannabis use disorder (75%). Unfavorable associations were also reported for anxiety (53%) and depression (41%). Therapeutic studies showed mixed results for anxiety and depression, with nearly half suggesting benefit, but a substantial proportion also indicating harm. No therapeutic studies found benefit for psychosis or schizophrenia.

Clinical impact: These findings reinforce concerns about the psychiatric risks of high-potency cannabis, particularly in non-medical contexts. While some therapeutic promise exists for mood disorders, the evidence is inconsistent and often low quality. Clinicians should counsel patients on the potential mental health risks of high-THC products and advocate for more rigorous research to guide safe use.

Source:

Rittiphairoj T, et al. (2025, August 26). Ann Intern Med. High-Concentration Delta-9-Tetrahydrocannabinol Cannabis Products and Mental Health Outcomes: A Systematic Review. https://pubmed.ncbi.nlm.nih.gov/40854216/