Gender differences in prepulse inhibition (PPI) in bipolar disorder: men have reduced PPI, women have increased PPI

Prepulse inhibition (PPI) is a measure of sensorimotor gating or information processing. Few studies have examined PPI in bipolar disorder (BD); two studies reported a PPI disruption and two reported no change. There are gender differences in PPI and within the clinical profile of BID, which may explain some of these discrepancies. Thus, the effect of gender on PPI in BID was the focus of the current study. Euthymic BID patients (14 male/15 female) were compared to age- and IQ-matched healthy control participants (16 male/16 female). Assessment of PPI included 21 pulse-alone trials (115 dB) and a total of 42 prepulse-pulse trials (seven of each prepulse: 74, 78, 86 dB) at two stimulus onset asynchrony levels (SOA: 60, 120 ms). There was a group x SOA and a group x gender interaction, reflecting that men with BD showed reduced PPI compared to control males at the 60-ms SOA (3% in BID vs. 26% in controls), but not the 120-ms SOA. In contrast, women with BD had significantly increased PPI compared to female controls at the 120-ms SOA (49% in BID vs. 29% in controls), but not the 60-ms SOA. Compared to control participants BD patients showed changes in PPI, which are gender-dependent; male BID participants had reduced PPI, whereas female BID participants had increased PPI. This gender difference highlights the need to consider men and women with BID as two distinct groups, at least in PPI studies.