Chronic administration of 13-cis-retinoic acid increases depression-related behavior in mice.

Retinoid signaling plays a well-established role in neuronal differentiation, neurite outgrowth, and the patterning of the anteroposterior axis of the developing neural tube. However, there is increasing evidence that nutritional vitamin A status and retinoid signaling play an important role in the function of the adult brain. 13-Cis-retinoic acid (13-cis-RA) (isotretinoin or Accutane), a synthetic retinoid that is an effective oral treatment for severe nodular acne, has been linked with depression and suicide in patients. The purpose of this study was to test the hypothesis that chronic administration of 13-cis-RA would lead to depression-related behaviors in mice. Young, adult male mice received 13-cis-RA (1 mg/kg) by daily intraperitoneal injection for 6 weeks. This treatment paradigm produced plasma levels of 13-cis-RA that are comparable to those reported in human patients taking Accutane. In both the forced swim test and the tail suspension test, we found that 13-cis-RA-treated mice spent significantly more time immobile compared to vehicle-treated controls. In the open field test, there was no change in anxiety-related behavior in 13-cis-RA-treated mice. Furthermore, chronic administration of 13-cis-RA did not impair locomotion in either the open field or the rotarod test. Taken together, these results suggest that administration of 13-cis-RA increases depression-related behaviors in mice.