Table 1.
Study characteristics
| Author | Country | Exposed | Controls | Age at follow up (s.d.) | Cannabis effect ‘d’ (CI) |
|---|---|---|---|---|---|
| Fried et al. (2005) | Canada | 38 | 59 | 17.86 (1.02) | −0.179 (−0.587 to 0.229) |
| Jackson et al. (2016) | USA (Minnesota) | 308 | 1387 | 18.06 (0.63) | −0.136 (−0.234 to −0.038) |
| Jackson et al. (2016) | USA (RFAB) | 118 | 193 | 17.89 (0.51) | −0.121 (−0.315 to 0.074) |
| Mokrysz et al. (2016) | UK | 74 | 1709 | 15 (not reported) | −0.009 (−0.224 to 0.242) |
| Meier et al. (2018) | UK | 132 | 1242 | 18 (not reported) | −0.15 (−0.330 to 0.029) |
| Meier et al. (2012) | New Zealand | 52 | 242 | 38 (not reported) | −0.45 (−0.752 to −0.148) |
| Ross et al. (2020) | USA | 86 | 476 | 17.25 (0.64) | −0.065 (−0.239–0.108) |