The effects of early life stress on reward processing

Abstract

Early life stress (ELS), in the form of childhood maltreatment, abuse, or neglect, increases the risk for psychiatric sequelae later in life. The neurobiology of response to early stress and of reward processing overlap substantially, leading to the prediction that reward processing may be a primary mediator of the effects of early life stress. We describe a growing body of literature investigating the effects of early life stressors on reward processing in animals and humans. Despite variation in the reviewed studies, an emerging pattern of results indicates that ELS results in deficits of ventral striatum-related functions of reward responsiveness and approach motivation, especially when the stressor is experienced in early in development. For stressors experienced later in the juvenile period and adolescence, the animal literature suggests an opposite effect, in which ELS results in increased hedonic drive. Future research in this area will help elucidate the transdiagnostic impact of early life stress, and therefore potentially identify and intervene with at-risk youth, prior to the emergence of clinical psychopathology.

Acute social isolation evokes midbrain craving responses similar to hunger

“…Rodents, for example, spontaneously seek social contact (35), fare better in group housing than in isolated housing (35,36) and cooperate with and help cage mates (37)(38)(39)(40). Extended periods of isolation, especially during development, can dramatically disrupt behavior and brain function (41,42). Even a brief acute period of social isolation in rodents induces an increased motivation for subsequent social interaction (43).…”

Beyond Broca’s area

“…For example, a large body of literature has demonstrated the ability of psychotherapy to alter brain activity in a way that promotes improved emotional regulation 7 . Early social experiences, such as a history of abuse and/or neglect, can blunt the brain's response to rewards in the environment (such as money or social praise), while increasing sensitivity to drugs of abuse 8,9 . A burgeoning literature is illustrating that one key mechanism through which experiences influence brain function is through alterations in gene expression, otherwise known as epigenetics.…”

The longitudinal stability of fMRI activation during reward processing in adolescents and young adults

“…Accordingly, a host of individual difference studies have sought to uncover potential mechanisms that may influence disease risk via their effects on reward processing, such as genetic risk and stress exposure (e.g. Banihashemi et al, 2014;Carey et al, 2017;Casement et al, 2015;Corral-Fríasa et al, 2015;Hanson et al, 2015bHanson et al, , 2015aJia et al, 2016;Kumar et al, 2015;Luking et al, 2016;Novick et al, 2018;Romens et al, 2015;Ruggeri et al, 2015). By examining possible causal mechanisms underlying mental illness, findings from this line of research have the potential to have a large impact on the development of novel treatment and prevention measures.…”