Allocation of attention in obsessional disorder.

It is suggested that obsessional disorders may be usefully described as a breakdown of cognitive control processes. Groups of obsessional, anxious and normal subjects were therefore tested on a task involving varying levels of attention, performed under normal and stressed conditions. Results provide some support for the hypothesis of attention failure under stress, but do not confirm that this is due to an underlying difference in the way obsessionals allocate attention.

Further observations of evoked potentials in obsessional patients.

This study was designed to replicate and extend earlier findings. Evoked potentials (EP) were recorded, using a task of varying complexity involving shape discrimination, with matched groups of obsessional and normal subjects. Results confirmed previous findings that obsessional patients are characterized by reduced amplitudes and decreased latencies of late EP components; divergences between the groups were more marked for tasks of increased complexity.

Some electrophysiological observations in obsessional states.

Averaged evoked potentials were recorded from a group of obsessional patients and matched normal controls for three types of visual stimulation: passive monitoring of a light flash, a pattern consisting of gratings and a cognitive task involving discrimination of two similar shapes. As the complexity of information processing required by the tasks increased, differences in the evoked potentials of obsessionals became more marked. The main finding was of faster latency and reduced amplitude of the N220 component in the cognitive task. The relevance of this finding to a theory of obsessional disorder is discussed.