Speed of Human Information Processing in Psychiatric Disorders

Reaction Time (RT) studies have reported psychomotorretardation in relation to Major Depression. However, theinterpretation of RT data is constrained because individuals canadopt different speed-accuracy trade-off strategies. InspectionTime (IT) is an index that is not prone to speed-accuracytrade-offs, and measures the speed of early information processing.It is essential to locate the earliest information processing stagein which a breakdown occurs because any subsequent stage may as aconsequence be impaired. IT may reflect the direct influence of theunderlying mediating mechanism involving neurotransmitter activity.Participants who were medically diagnosed with psychiatricdisorders were found to have longer ITs (slower speed ofinformation processing) than healthy controls. Un-medicatedpatients, expected to have the most depleted level ofneurotransmitter activity, were found to have the longest ITcompared to medicated and healthy controls. Increased IT was alsofound during electroconvulsive treatment. The analyses shed somelight on the underlying cognitive processes of psychiatricdisorders.