Bilateral electrodermal asymmetry in euthymic patients with unipolar and bipolar affective disorders.

Bilateral electrodermal activity (EDA) was examined in depressed patients in remission. In Study 1, 26 unipolar and 24 bipolar patients were compared to 46 psychiatrically healthy controls. Subjects were exposed to 17 86-dB pure tones while skin conductance was recorded from both hands. In Study 2, which was conducted 1 year later, many of these same subjects were recalled to form euthymic groups containing 22 unipolar, 22 bipolar, and 26 controls subjects. EDA was monitored bilaterally while subjects heard 8 86-dB tones and 12 105-dB tones followed by 8 familiar sounds that had a peak intensity of 105-dB. No consistent bilateral asymmetries in EDA were observed. Retest reliability coefficients indicating the stability of lateral differences over the 1-year period were close to zero. The results indicate that bilateral electrodermal asymmetry is not a trait characteristic of individuals prone to major affective disorder.