Three volumetric studies in adolescent chronic cannabis users were included, two of which consist of the same sample [154], [155]. As an exception, these two studies [154], [155] were included despite involving participants with symptoms of alcohol dependence given the modest number of studies included in this population (for details see Table 1). The MRI scans, focused on specific regions of interest and were obtained following 28 days of abstinence from cannabis use. Medina et al. (2009, 2010) [154], [155] reported significantly larger volumes of the inferior posterior vermis, as well as a marginal group-by-gender interaction in the prefrontal cortex, in which female and male cannabis users demonstrated, respectively, larger and smaller prefrontal cortex volumes compared to the same-gender controls. McQueeny et al. (2011) [156] also described an effect of gender in which female cannabis users but not males, exhibited a larger right amygdala volume.
