Anxiety as a Factor in the Development of Autistic Spectrum Symptoms: an Experimental Study

TL;DR

This study demonstrates that increased anxiety from social defeat in mice reduces sociability and exploratory behavior, and that anxiolytic treatment can reverse these effects, providing insights into autism-related social deficits.

Contribution

It shows that anxiety induced by social defeat causes autism-like social deficits in mice, and that anxiolytic treatment can restore normal social behavior, suggesting new avenues for understanding autism.

Findings

Social defeat increases anxiety and reduces sociability in mice.

Diazepam reduces anxiety and restores social behaviors.

Behavioral changes in defeated mice resemble autism symptoms.

Abstract

It is well known that psychoemotional disorders may be accompanied by decreased sociability in humans. It has been shown that repeated social defeats in 10 daily agonistic interactions in male mice led to development of the expressed level of anxiety and to reduction of communication estimated in the elevated plus-maze and partition tests, respectively. In the social interactions test, sociable behavior toward unfamiliar partner and exploratory activity were dramatically decreased in defeated male mice. Avoidance of approaching partner was significantly increased. Demonstration of self-grooming behavior was increased in defeated males. Chronic diazepam treatment (0.5 mg/kg, i.p., 2 weeks) led to significant decrease of anxiety level estimated in the elevated plus maze test and to improvement of communication in the partition test. In the social interaction test diazepam completely restored the level of sociability and exploratory activity and reduced avoidance behavior of approaching partner. Diazepam did not affect self-grooming demonstration. It is concluded that main factor which provokes decrease in communication in defeated male mice is the high level of anxiety. Similarity between changes in social behavior in defeated mice and symptoms of autism in humans is discussed. It is supposed that this behavioral approach may be useful for studying the molecular mechanisms of autistic spectrum disorders, developing under chronic negative social experiences.