Secretory Immunoglobulin A and Heart Rate Reactions to Mental Arithmetic and Hypnotic Suggestions

The current study replicates and extends previous research on the effects of both specific hypnotic suggestions and a mental arithmetic task on secretory immunoglobulin A (sIgA). Participants (14 males, 16 females) were shown a short video on immune functioning and then sat quietly for 8 minutes in order to obtain an initial baseline measure of sIgA. Participants were then administered an 8-min mental arithmetic (stress) task and a 16-min hypnosis task in a counterbalanced order and separated by a second 8-min baseline period. During the hypnosis condition, participants received a taped hypnotic induction followed by specific suggestions for increasing immune components in their saliva. During the mental arithmetic condition, participants received a taped 8-min paced auditory serial arithmetic test (PASAT). During the procedure, heart rate was continuously recorded at 5-sec intervals, and 4-min timed saliva samples were obtained immediately following both resting baselines and both tasks for subsequent sIgA analysis. Results showed a non-significant increase in sIgA levels following the mental arithmetic task, but a significant increase in both sIgA concentration and sIgA secretion rate following the hypnosis task. Results also demonstrated that the hypnosis task and mental stress task could be significantly distinguished by both physiological (heart rate) and experiential (questionnaire) measures. SIgA concentration following the hypnosis task was significantly greater than following the PASAT, suggesting that hypnosis is at least as powerful a technique as a mental stress task for increasing sIgA levels, without the corresponding increases in heart rate and subjective stress. However, within the 8-min resting condition immediately following the hypnosis task, sIgA levels decreased to below initial baseline levels, indicating that the effects of the hypnosis task are short lived. Potential mechanisms underlying the observed increases in sIgA are presented and implications about the clinical significance of these findings are discussed.