Marmosets, studied in their natural habitat using non-invasive fecal hormone measurements, are mainly monogamous, live in stable social groups with female competition and male cooperation, and form social bonds similar to humans, making them a potential model for social stress disorders. Laboratory studies confirm these behaviors and show sexually dimorphic responses to challenges influenced by age and social context. Their good adaptation to captivity, twin births, small size, and life cycle advantages have led to their use as animal models for psychiatric diseases like major depression. Juvenile marmosets have been used to develop a depression model and test Ayahuasca as an alternative treatment, with positive results encouraging further studies.
Chronic stress from social isolation in juvenile male marmosets reduces neuronal volume in the somatosensory cortex, a brain region implicated in depression. Ayahuasca, a psychedelic brew, given before and during isolation prevented this reduction, with treated animals showing neuronal volumes similar to non-stressed controls. Trends also suggested preserved cortical structure, though differences in neuronal density and overall cortical volume were not statistically significant. These results indicate ayahuasca may protect against stress-induced cortical atrophy and support further research into its therapeutic potential for stress-related psychiatric disorders, especially in adolescents.