Sensorimotor gating deficits in bipolar disorder patients with acute psychotic mania

Deficits in sensorimotor gating as assessed by prepulse inhibition (PPI) and habituation of the human startle response have been noted in schizophrenia and other patients with known dysfunction in the brain substrates that regulate PPI. During acute mania, bipolar disorder (BD) and schizophrenia patients present with symptoms that are similar. To determine if these clinical similarities extend to neurophysiologic domains, PPI and startle habituation were assessed in BD patients with acute psychotic mania and compared with a sample of acutely psychotic schizophrenia patients and a normal comparison group.

Fifteen BD patients, 16 schizophrenia patients, and 17 control subjects were assessed on PPI and startle habituation.

The BD patients had significantly lower PPI than did the control subjects in two of the three PPI conditions (60- and 120-msec interstimulus intervals) as well as less startle habituation. The BD patients did not statistically differ from the schizophrenia patients in PPI or habituation.

These findings of sensorimotor gating deficits among bipolar disorder patients are consistent with other findings using different measures of information processing and suggest that the neurobiological substrates underlying sensorimotor gating may be dysregulated during acute manic and psychotic states.