While short-term effects of cannabis on cognition are known, its long-term impact on cognitive decline is less clear. A new Danish study challenges assumptions, finding no significant cognitive harm associated with cannabis use over decades.
Researchers tracked 5,162 Danish men for 44 years, measuring IQ in early adulthood and late midlife using the Børge Prien’s Prøve (BPP). 39.3% of participants reported cannabis use.
Key findings
- Less cognitive decline in cannabis users:
- Users experienced 1.3 fewer IQ points decline than non-users, though the difference is modest.
- No impact of initiation age or frequency:
- Cognitive decline was not linked to early cannabis use or frequent consumption.
Strengths include the long follow-up and consistent testing. However, reliance on self-reported cannabis use, low participation rates, and the all-male sample limit generalization.
This study suggests cannabis use does NOT accelerate cognitive decline across adulthood. Further research is needed to confirm recovery effects and explore gender differences.