Table 2.
The strength of evidence concerning cannabis and cannabinoids in behavioral outcomes among persons without a medical condition or history of a psychiatric disorder.
| Behavioral Outcome | Number of studies finding a negative impact of cannabis use | Number of studies finding no impact of cannabis use | Level of Evidence |
|---|---|---|---|
| Verbal, Episodic, and Verbal Working Memory | 24 | 13 | 4 (24/37 = 64.9%) |
| Visuospatial Memory | 1 | 6 | 1 (1/6 = 16.7%) |
| Attention | 12 | 8 | 4 (12/20 = 60.0%) |
| Processing Speed | 3 | 3 | 3 (3/6 = 50.0%) |
| Executive Function | 16 | 8 | 4 (16/24 = 66.7%) |
| Impulsivity/Inhibitory Control | 10 | 7 | 3 (10/17 = 58.8%) |
| Intelligence (IQ) | 3 | 4 | 3 (3/7 = 42.9%) |
| Motivation | 4 | 2 | 4 (4/6 = 66.7%) |
| Psychosocial Functioning | 7 | 1 | 5 (7/8 = 87.5%) |
| Depression | 16 | 11 | 3 (16/27 = 59.3%) |
| Anxiety | 14 | 9 | 4 (14/23 = 60.9%) |
| Psychosis | 25 | 2 | 5 (25/27 = 92.6%) |
1 = 0–19% corresponds with strong evidence of no effects of cannabis use.
2 = 20–39% corresponds with moderate evidence of no effects of cannabis use.
3 = 40–59% corresponds with mixed evidence of neutral or negative effects of cannabis use.
4 = 60–79% corresponds with moderate evidence of negative effects of cannabis use.
5 = 80–100% corresponds with strong evidence of negative effects of cannabis use.