The Journal of Clinical Investigation study showed rats given a cannabinoid were less anxious and less depressed.
Apparently its effect was similar to that of the antidepressant drug Prozac, which also stimulates nerve growth in the hippocampus. The rats were less anxious and more willing to eat in a novel environment that would normally make them fearful.
The new research suggests that the size of the dose may be crucial. The results showed that regular injections of high, but not low, doses of the artificial cannabinoid HU210 were associated with anti-anxiety and antidepressive effects.
Cannabinoids appear to alter the effects of pain, nausea, tumours, sclerosis and other disorders in both animals and humans.
The study is published in the Journal of Clinical Investigation.