Sex differences in inter-temporal decision making and cortical thickness of the orbitofrontal and insula in young adult cannabis users: Evidence from 1111 subjects

To test for sex differences in the impact of cannabis use on decision-making and brain correlates, we employed cortical thickness (CT) analysis of brain regions involved in intertemporal decision-making namely bilateral orbitofrontal cortex(OFC) and insula in young adult nondependent cannabis-users(CU) and non-users(NU) and their scores on delay discounting task.

Neuroimaging analyzes of previously collected data were performed on 608CU and 503NU. CT analysis was performed on MRI images. OFC and insula thickness, scores on the delay discounting test were compared between groups and correlated.

Controlling alcohol-use and intra-cranial-volume, CU exhibited sex differences in CT. The bilateral insula was significantly thinner in male CU. OFC was thinner in females relative to controls. Female CU had thinner Right-medial OFC, Left-lateral-OFC. While male CU scored significantly lower on items within delay discounting task, female CU delay-discounting scores were within normal range.

Our results demonstrate that cannabis-use differentially affects decision-making across sexes. Cortical morphology mirrors this dimorphism. CU subjects did not show a correlation between CT of OFC or insula and delay discounting, implying that thinner cortices and lower DD scores in males may be independent alterations which may be premorbid to cannabis use and may lead to cognitive deficits in later years.