Rearing Experiences and Stress-Induced Plasma Cortisol as Early Risk Factors for Excessive Alcohol Consumption in Nonhuman Primates

Authors

  • Claudia Fahlke,

    Corresponding author
    1. Laboratory of Clinical Studies-Primate Unit (C.F., J.D.H.) and the Laboratory of Neurogenetics (J.G.L., J.L.), National Institute of Alcohol Abuse and Alcoholism, Bethesda; and the Laboratory of Comparative Ethology, National Institute of Child Health and Human Development (M.C., S.J.S.), National Institutes of Health Animal Center, Poolesville, Maryland.
      Reprint requests: Claudia Fahlke, PhD, Department of Psychology, Göteborg University, Box 500, SE-405 30 Göteborg, Sweden; Fax: 46-31-7734628; E-mail: claudia.fahlke@psy.gu.se
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  • Joseph G. Lorenz,

    1. Laboratory of Clinical Studies-Primate Unit (C.F., J.D.H.) and the Laboratory of Neurogenetics (J.G.L., J.L.), National Institute of Alcohol Abuse and Alcoholism, Bethesda; and the Laboratory of Comparative Ethology, National Institute of Child Health and Human Development (M.C., S.J.S.), National Institutes of Health Animal Center, Poolesville, Maryland.
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  • Jeffrey Long,

    1. Laboratory of Clinical Studies-Primate Unit (C.F., J.D.H.) and the Laboratory of Neurogenetics (J.G.L., J.L.), National Institute of Alcohol Abuse and Alcoholism, Bethesda; and the Laboratory of Comparative Ethology, National Institute of Child Health and Human Development (M.C., S.J.S.), National Institutes of Health Animal Center, Poolesville, Maryland.
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  • Maribeth Champoux,

    1. Laboratory of Clinical Studies-Primate Unit (C.F., J.D.H.) and the Laboratory of Neurogenetics (J.G.L., J.L.), National Institute of Alcohol Abuse and Alcoholism, Bethesda; and the Laboratory of Comparative Ethology, National Institute of Child Health and Human Development (M.C., S.J.S.), National Institutes of Health Animal Center, Poolesville, Maryland.
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  • Stephen J. Suomi,

    1. Laboratory of Clinical Studies-Primate Unit (C.F., J.D.H.) and the Laboratory of Neurogenetics (J.G.L., J.L.), National Institute of Alcohol Abuse and Alcoholism, Bethesda; and the Laboratory of Comparative Ethology, National Institute of Child Health and Human Development (M.C., S.J.S.), National Institutes of Health Animal Center, Poolesville, Maryland.
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  • J. Dee Higley

    1. Laboratory of Clinical Studies-Primate Unit (C.F., J.D.H.) and the Laboratory of Neurogenetics (J.G.L., J.L.), National Institute of Alcohol Abuse and Alcoholism, Bethesda; and the Laboratory of Comparative Ethology, National Institute of Child Health and Human Development (M.C., S.J.S.), National Institutes of Health Animal Center, Poolesville, Maryland.
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  • Staff and research were supported by intramural research funding from the National Institute of Alcohol Abuse and Alcoholism and the National Institute of Child Health and Human Development, Bethesda, Maryland, and by the Swedish Medical Research Council (K98-21P-1184203A).

    The research protocol was approved by the National Institutes of Health, Bethesda, MD, in accordance with and as required by the Animal Welfare Act.

Reprint requests: Claudia Fahlke, PhD, Department of Psychology, Göteborg University, Box 500, SE-405 30 Göteborg, Sweden; Fax: 46-31-7734628; E-mail: claudia.fahlke@psy.gu.se

Abstract

Background: The purpose of this study was to assess the impact of early rearing and stress-induced rise of plasma cortisol collected during infancy as a biological predictors of adult alcohol consumption in nonhuman primates.

Methods: Ninety-seven female and male rhesus macaques (Macaca mulatta) were investigated. They were reared for their first 6 months of life either without mothers or other adults but with constant access to same-aged peers (peer-reared), or as controls with their mothers (mother-reared). When subjects reached 6 months of age, they underwent a series of four sequential weeks of 4-day social separations. Blood was drawn 1 and 2 hr after initiation of the 4-day separation periods, and the plasma was assayed for plasma cortisol concentrations. When the subjects were young adults (approximately 50 months of age), they were tested for voluntary intake of alcohol for 1 hr per day, 4 days a week, during a period of 5 to 7 weeks under normal living conditions.

Results: The social separation challenge increased infant plasma cortisol concentrations, with peer-reared subjects exhibiting higher stress-induced cortisol concentrations than mother-reared animals. Subjects that responded to the social separation challenge with high cortisol levels consumed significantly more alcohol per kilogram of body weight as adults than subjects with a low cortisol response to the separation challenge, regardless of rearing condition. In addition, male and peer-reared subjects consumed significantly more alcohol than female and mother-reared subjects, respectively.

Conclusions: These findings suggest that early rearing experiences, such as adult absence, and high plasma cortisol concentrations early in life after a social separation stressor, are useful psychobiological predictors of future high alcohol consumption among nonhuman primates.

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