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. Author manuscript; available in PMC: 2021 Nov 25.
Published in final edited form as: Drug Alcohol Depend. 2020 May 25;213:108063. doi: 10.1016/j.drugalcdep.2020.108063

Figure 2. White matter volumes : Partial correlations with verbal learning and dependency severity.

Figure 2.

A) The Total white matter volumes were significantly different across the three groups (ANCOVA-p=0.009). Ketamine polydrug (K+PolyS) users had larger white matter volumes than ND users (p=0.011) and Primarily-K users (p=0.050), covaried for age and sex, with a linear trend showing K+PolyS>Primarily-K>Non-drug users (p=0.004). Adjusted p-values were derived from Tukey’s post hoc tests. In addition, all ketamine users combined had larger white matter volumes than ND controls (p=0.046). B) Across all participants (blue line), larger white matter volumes predicted better verbal learning, after adjustments for age, sex and education (r=0.21, p=0.019). C) Across both ketamine user groups (brown line), earlier age of onset of ketamine use (years) predicted larger white matter volumes (r=−0.27, p=0.015). D) Across both ketamine user groups (brown line), larger white matter volumes predicted more severe drug dependency, after adjustments for age and sex (r=0.23, p=0.044).