Behavioral effects of mefloquine in tail suspension and light/dark tests

Mefloquine hydrochloride has been used widely in the past few decades for malaria prophylaxis and treatment. However, in recent years, it has fallen out of favor due to reports of exposure being linked to numerous neuropsychiatric effects, including emotional disturbances. In this study we examined the effects of different doses (5, 25, or 100 mg/kg) of mefloquine relative to vehicle on male C57BL/6 J mice in two tests of emotional behavior, the light–dark box and the tail suspension test. It was found that mefloquine exposure reduced anxiety-linked behaviors in the light–dark box and reduced total immobility times in the tail suspension test, especially at higher doses. Our results lend support to the notion that mefloquine exposure could induce emotional disinhibition.