Interoception in Fear Learning and Posttraumatic Stress Disorder

What is it about?

PTSD is a fear-related psychiatric disorder triggered by the experience of one or more threatening and traumatic events. A traumatic event can be thought of as a concentrated time during which an individual learns to associate neutral internal and external bodily signals with the threat and then becomes fearful of them. This fear learning occurs consciously as well as unconsciously and is considered central to the development and maintenance of PTSD symptoms. In this article we explain how fear learning during and after a traumatic experience may be influenced by interoception, the way that the nervous system senses and interprets the meaning of internal body signals such as a pounding heartbeat or sweaty palms. For example, interoceptive signals during a traumatic event (such as a pounding heartbeat) may amplify subsequent feelings of threat when exposed to an associated signal present during the trauma (such as the smell of gasoline during an explosion), even when the cue is subsequently presented in a safe setting (for example, the smell of gasoline at a gas station). We argue that increased sensitivity to interoceptive signals modifies how the trauma is remembered and leads to new forms of fear learning whereby subtle changes in the body (such as slight increases in heart rate while at the gym) can elicit full-blown fear responses and attempted avoidance of perceived internal or external bodily triggers, through a process called higher-order fear learning. Although fear learning has been a large focus of PTSD research, the role of interoception in this form of learning has largely been unexplored. We summarize prior neural and behavioral research on interoception and fear learning in PTSD, and we propose some ways that individual differences in the awareness and integration of interoceptive signals may reinforce or interfere with fear learning processes and related PTSD symptoms. Finally, we propose new avenues for examining the role of interoception in treatment approaches for PTSD.

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Photo by Nick Fewings on Unsplash

Photo by Nick Fewings on Unsplash

Why is it important?

The role of interoception in fear learning has largely been unexplored, even though interoceptive sensations such as a pounding heartbeat or difficulty breathing are commonly associated with trauma symptoms. Considering the role of interoception in the fear learning processes central to PTSD may help us to better understand the individual characteristics that make someone susceptible to developing PTSD following a traumatic event. It may also lead to strategies that could improve the efficacy of current treatments, or to the development of new treatments for PTSD.

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