An acne treatment blamed for triggering suicides in young people has been shown to cause depressive behaviour in animal tests.

The finding lends support to claims that Roaccutane, not the acne, may have led to the affected individuals taking their own lives.

Sarah Bailey from the University of Bath and Michelle Lane from the University of Texas found when the drug was given to mice it left the animals immobile for longer periods than normal during stress tests. Dr Bailey, writing in Neuropsychopharmacology, said further research was needed in humans. Roche, the manufacturer, said there was no proven link with suicide but the company was "constantly monitoring" safety.