Panic patients in the non-panic state: physiological and cognitive dysfunction.

Panic attacks and the antipanic effect of antidepressants are claimed to distinguish panic disorder (PD) from generalised anxiety disorder. However, most studies showing neurochemical disturbances in PD overlook the non-panic state. We compared panic patients in the non-panic state with controls on biochemical, psychological and physiological measures. There were no differences on the neuroendocrine tests. Self-ratings of bodily and psychological symptoms of anxiety were significantly higher in patients and they scored worse on word recall. Patients had significantly more skin conductance fluctuations and slow wave activity in the electroencephalogram, a sign of hyperventilation which may have implications for brain activity. Discrepancies between patients' self-ratings and objective measures of pulse rate and psychomotor performance indicated that panic patients have distorted perceptions of both physical and mental functioning. Hyperventilation and cognitive distortions in the non-panic state may facilitate panic attacks and are part of the pathophysiology of PD.