Childhood adversity linked to fear overgeneralization and reduced safety learning in teens

A study of adolescents who experienced childhood adversity found that they were less able to distinguish between signals of safety and threat in an experimental setting. This impaired threat-safety discrimination was associated with a tendency to overgeneralize their fear responses. The study was published in the Journal of Child Psychology and Psychiatry.

Childhood adversity includes a range of stressful or traumatic experiences, such as abuse, neglect, household dysfunction, and exposure to violence. It is associated with disruptions in brain development, particularly in regions involved in emotional regulation and stress response, including the amygdala and prefrontal cortex. Chronic exposure to adversity can alter the functioning of the hypothalamic-pituitary-adrenal axis, resulting in heightened physiological reactivity to stress.

Children who face such adversity are at increased risk for developing mental health conditions such as anxiety, depression, and posttraumatic stress disorder. They may also experience difficulties with emotion regulation, social functioning, and cognitive performance. In adulthood, early adversity is linked to poor health outcomes, including cardiovascular disease, substance use disorders, and chronic inflammation.

Lead author Celine Samaey and her colleagues aimed to investigate how childhood adversity influences fear learning during adolescence—specifically, whether adolescents who had experienced adversity would show impairments in distinguishing safe from threatening cues and a greater tendency to generalize fear responses.

The study involved 119 adolescents between 12 and 16 years old, with an average age of 14. Sixty-five participants were girls, and 63 had been exposed to childhood adversity, as assessed by the abbreviated Juvenile Victimization Questionnaire – 2nd Revision.

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Participants completed two key experimental tasks. In a fear conditioning task, they viewed circles of different sizes. One specific circle (designated CS+) was occasionally followed by a mild electric shock to the wrist, while another (CS–) was never followed by a shock. After learning this association, participants were shown additional circles of varying sizes and asked to rate how likely they thought it was that each circle would be followed by a shock. This allowed researchers to assess how broadly participants generalized fear to stimuli that resembled the threatening one.

Participants also completed a perceptual discrimination task, where they had to judge whether pairs of circles were the same or different in size. This test was used to determine whether generalization of fear might be due to difficulty distinguishing the visual stimuli.

As the fear conditioning task progressed, participants generally became more likely to expect an electric shock. Girls reported lower shock expectancy overall compared to boys.

Importantly, adolescents with greater exposure to childhood adversity were more likely to expect shocks, even for stimuli that were not followed by shocks. Boys who had experienced adversity gave higher threat ratings to the safe circle and to other generalization stimuli than boys without such experiences. Girls exposed to adversity showed elevated threat expectations for nearly all stimuli except the most extreme generalization stimulus.

This pattern suggests that adolescents who experienced childhood adversity were more prone to generalizing fear and had a reduced ability to distinguish between threatening and safe cues. Interestingly, those exposed to adversity were not worse at visually distinguishing the circles—in fact, they tended to perform better in the perceptual discrimination task. This indicates that their increased fear generalization was not due to perceptual confusion but rather to differences in emotional learning.

“The current study showed that CA [childhood adversity] is associated with reduced threat-safety discrimination and increased fear generalization during adolescence. As such, altered fear learning emerges as an important process through which adversity increases risk for the development of psychopathology,” the,” study authors concluded.

The study sheds light on the links between childhood adversity experiences and fear learning. However, it should be noted that the study used a very mild electric shock as the object of fear. The patterns of learning to respond to serious threats or dangers might not be the same.

The paper, “Childhood adversity is associated with reduced threat-safety discrimination and increased fear generalization in 12- to 16-year-olds,” was authored by Celine Samaey, Aleksandra Lecei, Maarten Jackers, Lise Jennen, Koen Schruers, Bram Vervliet, Bart Boets, and Ruud van Winkel.