Startle response during smoking and 24 h after withdrawal predicts successful smoking cessation

Rationale: The startle response is thought to reflect changes in attentiona l processes in humans. The startle response shows a number of forms of plas ticity, of which prepulse inhibition (PPI) refers to the attenuation of the startle response to a strong sensory stimulus (pulse), when such a pulse i s preceded by a stimulus of lower intensity (prepulse). Recent studies have shown that nicotine modulates startle and PPI of the startle reflex in hum ans and animals. The present study examined individual differences in cogni tive benefits obtained from smoking as indexed by startle response and PPI. Objectives: We investigated, using a within-subjects design, the effects o f cigarette smoking via a comparison of baseline and withdrawal measures of startle and PPI in 18 subjects wishing to quit cigarette smoking. The rela pse of five of these subjects enabled a between-group comparison of these m easures with the successful quitters. Methods: Startle and PPI were measure d on three separate occasions: before quitting, 24 h after quitting and I m onth after quitting. Results: The presence of a high startle response ampli tude while subjects were still engaged in their normal smoking patterns (ba seline) and the occurrence of a significant drop of startle amplitude in wi thdrawal relative to baseline factors were found to be predictive of an ind ividual's ability to quit smoking. Changes in PPI were found to reflect the se changes in startle amplitude. Conclusions: The observed response pattern s are discussed in terms of individual differences in commitment to quittin g and self-dosing to manipulate attentional mechanisms as measured by the a coustic startle response. Furthermore, it is suggested that these specific response profiles may be predictive of the ability to quit smoking.