Stress and the social brain

As noted in a review article by Carmen Sandi, from the Brain Mind Institute at the EPFL and József Haller, from the Hungarian Academy of Sciences, stress often affects our social lives. “When undergoing high-level or persistent stress, individuals frequently retract from social interactions and become irritable and hostile. Predisposition to antisocial behaviours — including social detachment and violence — is also modulated by early life adversity; however, the effects of early life stress depend on both the timing of exposure as well as genetic factors. Research in animals and humans has revealed some of the structural, functional and molecular changes in the brain that underlie the effects of stress on social behaviour.”

In the review, “stressors experienced in different phases of the lifespan are shown to affect individuals’ interest in and reactions towards conspecifics — including social motivation, social recognition and aggression — and consider the mechanisms that mediate such effects. Although there remain many gaps in our knowledge, the evidence accumulated so far has revealed surprisingly specific associations between the characteristics and concomitants of stress and its immediate and long-term consequences for brain function and social behaviours.

The emerging model suggests that social withdrawal in adulthood is a general consequence of experiencing, or having experienced, high and persistent stress levels, regardless of the developmental period (prenatal, early postnatal, juvenile or adulthood) when the episode occurs. Similarly, aggression tends to be facilitated by stress (acute, chronic or developmental) unless the stress is inflicted by social defeat, which has an inhibitory effect on aggressive behaviour. From a developmental perspective, stress seems to impose a progressive pattern of dysfunctional social behaviour that begins with asociality (elicited by prenatal stressors), progresses to hostility (which emerges when stress is suffered postnatally) and ends with antisociality (which seems particularly bound to stress experienced in the juvenile period).

Much progress still remains to be made to increase our understanding of how the social brain works, and we are only beginning to reveal how stress can interact with social brain function. But this understanding will guide the development of novel treatment strategies. For example, neurochemical mechanisms that favour a pro-social attitude (such as oxytocin) might be used to develop pharmacological tools to reverse undesirable changes in neuronal communication that are caused by stress. Epigenetic mechanisms could be considered as alternative targets for intervention.”

Carmen Sandi and József Haller, Stress and the social brain: behavioural effects and neurobiological mechanisms, in Nature Reviews Neuroscience, 2015 May 20, doi:10.1038/nrn3918