Startle potentiation to unpredictable threat and the internalizing spectrum

Area of Science:

• Psychiatry and Psychology
• Psychophysiology
• Internalizing Disorders

Background:

• Increased sensitivity to ambiguity and unpredictability is noted in various psychiatric disorders.
• Heightened startle potentiation to unpredictable threat is observed in anxiety and trauma-related disorders.
• Previous research shows mixed findings for depression and generalized anxiety disorder.

Purpose of the Study:

• To investigate the association between heightened startle potentiation to unpredictable threat and the higher-order internalizing spectrum.
• To determine if startle potentiation to unpredictable threat is a transdiagnostic marker for internalizing disorders.

Main Methods:

• A sample of 193 young adults (18-35 years) was recruited, oversampled for psychiatric disorders.
• Participants underwent the Structured Clinical Interview for DSM-5 to assess lifetime psychiatric history.
• Startle potentiation to predictable and unpredictable threat was measured using a threat task.

Main Results:

• Heightened startle potentiation to unpredictable, but not predictable, threat was found in participants with a history of major depressive episode, generalized anxiety disorder, PTSD, specific phobia, OCD, and eating disorder.
• Higher-order mediational modeling revealed that greater startle potentiation to unpredictable threat was associated with a latent internalizing dimension.
• This internalizing dimension explained all associations between startle potentiation to unpredictable threat and individual disorders; no link was found with externalizing disorders.

Conclusions:

• Heightened startle potentiation to unpredictable threat is robustly associated with the internalizing spectrum of psychiatric disorders.
• This finding suggests a core psychophysiological mechanism underlying internalizing conditions.
• Higher-order dimensional approaches can enhance the understanding of core mechanisms in psychiatric disorders.