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The Development of Trait Anxiety in Nonhuman Primates During the First Year of Life
Rachel Puralewski1, Nakul Aggarwal1, Jonathan A Oler1
1Department of Psychiatry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA.
Insights
Anxious temperament (AT), a predictor of anxiety disorders, emerges in infant primates within weeks. This behavioral inhibition trait remains stable throughout the first year, reaching maturity by 52 weeks.
Area of Science:
- Primate behavior
- Developmental psychology
- Neuroscience
Background:
- Anxious temperament (AT) in nonhuman primates models human childhood behavioral inhibition.
- Behavioral inhibition is a significant risk factor for anxiety disorders and stress-related psychopathology.
- Understanding the early development of AT is crucial for identifying risk factors for psychopathology.
Purpose of the Study:
- To characterize the developmental trajectory of anxious temperament (AT) in infant primates during their first year of life.
- To examine the stability of individual differences in AT and its components across development.
- To identify the earliest antecedents of AT in primate development.
Main Methods:
- Longitudinal phenotyping of infant monkeys (n=35) over the first 52 weeks of life.
- Assessment of AT through threat-related freezing behavior, coo-calling, and plasma cortisol levels.
- Statistical analysis to determine developmental trends and stability of AT components.
Main Results:
- AT levels showed a linear increase, reaching mature levels by 52 weeks of age.
- Individual differences in AT and its behavioral/hormonal components were stable throughout development.
- AT and its components are present from the earliest weeks of primate life.
Conclusions:
- Anxious temperament is an early-developing, stable phenotype in primates.
- These findings support further research into the neurobiological underpinnings of AT during early development.
- Understanding primate AT development may offer insights into human anxiety disorders.
Abstract:
Anxious temperament (AT) is a nonhuman primate phenotype that models childhood behavioral inhibition, a prominent risk factor for anxiety disorders and stress-related psychopathology. To understand its earliest antecedents, we characterized AT's developmental trajectory over the first year of life. Infant monkeys (n = 35, 24 females) were longitudinally phenotyped for AT by assessing threat-related increases in freezing behavior, reductions in coo-calling, and increases in circulating cortisol at 1.5, 6, 12, 24, and 52 weeks. AT levels increased linearly, reaching mature levels by 52 weeks. Individual differences in AT, and its components, were stable across development. These findings support further studies during early primate life aimed to uncover neurobiological factors mediating development of this phenotype, which in humans is linked to stress-related psychopathology. SUMMARY: Anxious temperament (AT) or behavioral inhibition (BI), a trait-like characteristic in humans associated with later development of anxiety-related psychopathology, is evident during earliest weeks of primate life. Developmental patterns of AT and its components (threat-related freezing, reductions in cooing, increases in plasma cortisol) across the first year of primate life are presented. Individual differences in AT and its behavioral and hormonal components are relatively stable across the first year of life, reaching maturity by one year.
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