CCK-4: Psychophysiological conditioning elicits features of spontaneous panic attacks

Area of Science:

• Neuroscience
• Psychiatry
• Human Physiology

Background:

• Cholecystokinin-tetrapeptide (CCK-4) is a validated model for inducing subjective panic anxiety and dose-dependent stress hormone elevation.
• Previous research has minimally explored CCK-4's impact beyond subjective panic and stress hormones.

Purpose of the Study:

• To investigate the effects of CCK-4 on emotional facial expressions.
• To specifically examine CCK-4's influence on fear-relevant facial muscles.
• To establish a more objective method for measuring subjective panic anxiety.

Main Methods:

• 20 healthy males were randomly assigned to placebo, 25 μg CCK-4, or 50 μg CCK-4 groups in a double-blind manner.
• Subjects underwent three investigations with balanced orders of CCK-4 and placebo administration.
• Facial muscle activity and hypothalamo-pituitary-adrenocortical (HPA)-axis activity were recorded.

Main Results:

• CCK-4 administration resulted in a dose-dependent increase in panic anxiety, fear-relevant facial muscle activation, and elevated stress hormones.
• Placebo administration prior to CCK-4 showed no significant panic or stress response.
• A psychophysiological conditioning effect was observed during placebo administration following CCK-4, without concurrent HPA-axis activity increase.

Conclusions:

• Facial electromyography (EMG) can measure varying intensities of panic anxiety and conditioning effects.
• The dissociation between HPA-axis activity and fear-relevant facial muscle activation aligns with prior findings on spontaneous panic attacks.