Reduced prepulse inhibition is associated with increased hypnotizability

Hypnosis involves the manipulation of conscious attentional discrimination. The prepulse inhibition (PPI) paradigm assesses primary unconscious information processing. We investigated the correlation between hypnotizability and PPI of the startle reflex. Forty-eight healthy subjects were evaluated with the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) and acoustic PPI. Subjects were divided into low, medium, and high hypnotizable groups. The low-hypnotizable group showed a significantly higher inhibition of the startle response, at lead intervals 60 ms and 120 ms, than did the medium- and high-hypnotizable groups. We conclude that hypnotizability and PPI may be negatively correlated. These findings lend further support for the role of dopaminergic neurotransmission mechanisms in the determination of hypnotizability levels.