Spatial attention and neural asymmetry in obsessive-compulsive disorder.

Patterns of lateralized dysfunction in obsessive-compulsive disorder (OCD) were examined using the Posner spatial attention paradigm. While controls responded faster to left visual field targets than to right, patients lacked this asymmetry. The difference in asymmetry patterns was significant for the invalid cue condition, but not for the valid cue condition. Reversal of normal asymmetry was correlated with obsession severity. Findings support aberrant hemispheric balance in OCD.