Visual impairments in type 1 bipolar disorder

Abstract

Abstract Objectives: The present study evaluated early visual processing, in terms of the contrast sensitivity function (CSF), in bipolar disorder (BPD) patients. Methods: Data were recorded in 17 healthy participants and 17 outpatients with type 1 BPD, from 20 to 45\u2009years of age. The CSF was measured at spatial frequencies of 0.2, 0.6, 3.1, 8.0, 16.0 and 20.0 cycles per degree (cpd) using Gabor patches and a two-alternative, forced-choice, logarithmic staircase method. The groups were matched for gender, age and level of education. Results: The CSF differed between groups. Patients with BPD had lower discrimination at spatial frequencies of 0.2 cpd (P\u2009<\u20090.001), 0.6 cpd (P\u2009<\u20090.001), 16.0 cpd (P\u2009<\u20090.001) and 20.0 cpd (P\u2009<\u20090.001) compared with healthy subjects. No differences were observed at 3.1 cpd (P\u2009>\u20090.05) and 8.0 cpd (P\u2009>\u20090.05). This visual impairment was related both to longer duration of illness and to greater severity of manic symptoms. Conclusions: The differences in visual processing were pronounced in patients with BPD, which justifies further investigations of the pathophysiological mechanisms that are involved in sensorial alterations.