CBD Reduced Depression-Like Behavior and Protected Memory in Socially Isolated Mice

CBD mitigated anhedonia (loss of pleasure) and reduced immobility in the tail suspension test in socially isolated mice. CBD also protected recognition memory that was impaired by isolation. However, CBD did not have anxiolytic effects and unexpectedly increased anxiety-like behavior in group-housed (non-stressed) mice. Social isolation reduced hippocampal BDNF expression, while CBD preserved it in isolated mice.

Adult C57BL/6 male mice were subjected to 12 weeks of social isolation or group housing with chronic CBD administration. Behavioral tests included sucrose preference, open field, light/dark box, novel object recognition, and tail suspension. Hippocampal gene expression for CB1R, 5HT1AR, and BDNF were analyzed.

Social isolation is a major contributor to depression and cognitive decline. This study shows CBD has specific antidepressant and neuroprotective effects in an isolation model, though its anxiogenic effects in non-stressed animals highlight the context-dependent nature of CBD's actions.

The dual finding that CBD helps depression-like symptoms in stressed mice but can increase anxiety in non-stressed mice aligns with clinical observations that CBD effects depend heavily on context, baseline state, and individual variation.

Male mice only. One dose of CBD tested. Social isolation model does not fully replicate human depression. 12-week isolation is extreme. The anxiogenic effect in non-stressed mice needs replication and mechanistic investigation.