Fluoxetine but not risperidone increases sociability in the BTBR mouse model of autism

Autism, a neurodevelopmental disorder, is characterized by abnormal social interactions, impaired social communication and repetitive behaviors and/or restricted interests, along with several associated symptoms including irritability and anxiety. Risperidone is approved for the irritability and self-injurious behaviors found in autism. Fluoxetine is under evaluation for the repetitive behaviors and anxiety associated with autism. These two drugs were evaluated in the BTBR T+tf/J (BTBR) mouse model of autism and C57BL/6J (B6) mice by using the three-chambered social approach test and elevated plus maze to determine effects on sociability and anxiety. Fluoxetine increased sociability, defined as time spent with a stranger mouse, in the BTBR mice without affecting anxiety-like behavior in the elevated plus maze. Fluoxetine did not significantly change either behavior in the B6 mice. Risperidone did not affect sociability or anxiety-like behaviors and had a sedative-like effect at higher doses. These findings suggest that fluoxetine may have some therapeutic efficacy for treating the social behaviors in autism.