Fronto-temporal cortical atrophy in 'nyaope' combination heroin and cannabis use disorder

Sub-Saharan Africa is one of the top three regions with the highest rates of opioid-related premature mortality. Nyaope is the street name for what is believed to be a drug cocktail in South Africa although recent research suggests that it is predominantly heroin. Nyaope powder is most commonly smoked together with cannabis, a drug-use pattern unique to the region. Due to the increasing burden of this drug in low-income communities and the absence of human structural neuroimaging data of combination heroin and cannabis use disorder, we initiated an important cohort study in order to identify neuroanatomical sequelae. Twenty-eight male nyaope users and thirty healthy, matched controls were recruited from drug rehabilitation centers and the community, respectively. T1-weighted MRI images were obtained using a 3 T General Electric Discovery and cortical thickness was examined and compared. Nyaope users displayed extensive grey matter atrophy in the right hemispheric medial orbitofrontal, rostral middle frontal, superior temporal, superior frontal, and supramarginal gyri (two-sided t-test, p < 0.05, corrected for multiple comparisons). Our findings indicate cortical abnormality in nyaope users in regions involved in impulse control, decision making, social- and self-perception, and working memory. Importantly, affected brain regions show large overlap with the pattern of cortical abnormalities shown in heroin use disorder.

Automated summary

Sub-Saharan Africa is one of the top regions with high rates of opioid-related premature mortality, where the street drug "Nyaope" is believed to be a cocktail of drugs, predominantly heroin with cannabis. The study found extensive grey matter atrophy in specific brain regions of Nyaope users, impacting impulse control, decision making, social- and self-perception, and working memory. These affected brain regions overlap with cortical abnormalities observed in heroin use disorder.