Sex-dependent hippocampal atrophy among people with methamphetamine-use experience

As methamphetamine use rates continue to climb, understanding its relationship with physical, mental, and cognitive decline is critical. While memory difficulties are common, the underlying neurobiology of these deficits are not well understood. Preclinical work suggests that, at least among male subjects, methamphetamine exposure results in volume loss in the hippocampus, a critical brain region supporting memory outcomes. Human studies investigating the effect of methamphetamine use on hippocampal volume have been equivocal. These inconsistencies may relate to sex differences and varying degrees of use and abstinence in study samples. The current study evaluated hippocampal volume and associated hippocampal-dependent memory in a sex-balanced community sample of people with recent problematic methamphetamine-use experience $(N=90)$ and methamphetamine-naïve controls $(N=90)$ . While group differences in hippocampal volumes were evident for males with methamphetamine-use experience compared to the control group, no such differences were evident for females. However, hippocampal-dependent memory performance (i.e., delayed verbal recall performance) was impaired for both males and females with methamphetamine-use experience and both hippocampal volume and methamphetamine-use experience explained unique and significant variance in memory performance. These findings highlight the importance of considering sex-differences in methamphetamine addiction research.