Researchers have found that male rhesus monkeys who tend to shun group play, mutual grooming and other social activities have a subtle thing in common with boys who have an autism spectrum disorder. In both cases, they have unusually low levels of a hormone called vasopressin.

Outside the brain, vasopressin helps regulate blood pressure and fluid retention. But in the brain, it has long been thought to play a role in social, sexual and nurturing behavior. And because it interacts with male hormones such as testosterone, some scientists suspect it could be implicated in autism, which affects boys at about four times the rate that it does girls.

So researchers from Stanford University, UC San Francisco and UC Davis decided to explore whether vasopressin levels might be a biological marker for autism. In both humans and rhesus monkeys, they found, levels of the hormone in cerebrospinal fluid — generally a clue to its concentration in the brain — were markedly higher in individuals without social deficits than they were in the least social members of both groups.

Read the full article here