Table 8.
Summary of significant correlations found between measures of white matter integrity and indices of cannabis use, cognition, alcohol use, and mental health where findings were investigated in 4 or more studies.
| FA | MD | RD | AD | Other | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ↓ | ↑ | ↓ | ↑ | ↓ | ↑ | ↓ | ↑ | ↑ | ||||||||||||||||||||||||||||||
| CC | ILF | FMi | ATR | UF | CC | ILF | UF | LP | FR | CG | SLF | PFC | FMi | FMa | OF | SCR | MCP | ILF | CC | FR | MCP | CC | ATR | SLF | CC | MCP | ILF | LP | AB | FMi | CF | FIM | CG | MCP | CF | CG | GE | |
| Age of onset | - | - | - | - | - | 4 | 2 | 1 | 1 | - | - | 1 | 1 | 1 | 1 | - | - | - | - | 1 | 1 | - | - | - | 1 | 1 | - | 1 | 1 | - | - | 1 | 1 | 1 | - | 1 | - | - |
| Duration | 1 | 1 | 1 | - | - | - | - | - | - | - | - | 1 | - | - | - | 1 | - | - | - | 1 | - | - | 2 | - | - | - | - | - | - | 1 | 1 | - | - | - | - | - | 1 | - |
| Dosage | - | - | - | 1 | - | - | - | - | - | - | 1 | 1 | - | 1 | - | - | 1 | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Frequency | - | - | - | - | - | - | - | - | - | - | - | 1 | - | - | - | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Impulsivity | 2 | - | - | - | - | 1 | - | - | - | 2 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Neurocognition | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Memory | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Alcohol use | - | - | - | - | - | - | - | - | - | - | - | - | - | – | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 1 |
| Mental health | - | - | 1 | 2 | - | - | - | - | - | - | - | - | - | - | - | - | - | – | - | - | - | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | |
| Craving | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 1 | - | - | - | 1 | - | - | - | - | 1 | - | - | - | - | - | - | - | 1 | - | - | - | |
↓, negative correlation; ↑, positive correlation; -, not examined; AD, axial diffusivity; FA, fractional anisotropy; MD, mean diffusivity; RD, radial diffusivity. White Matter Tracts: CC, corpus callosum; CG, cingulate gyrus, listed grey matter region in results, suggests white matter tracts within region; ATR, anterior thalamic radiations; FMi, forceps minor; FMa, forceps major; FR, frontal region, listed grey matter region in results, suggests white matter tracts within region; OF, occipito-frontal; SCR, superior corona radiata clusters; FIM, fimbria; AB, angular bundle; CF, commissural fibres; GE, global efficiency, graph theory metric, not a white matter tract; SLF, superior longitudinal fasciculus; ILF, inferior longitudinal fasciculus; UF, uncinate fasciculus; LP, lateral prefrontal cortex, listed grey matter region in results, suggests white matter tracts within region; AB, angular bundle.