Depression in schizophrenia: I. Association with neuropsychological deficits

The presence of depression in schizophrenia has been well described with regard to stage and symptoms of illness; however, little is known about the possible etiology.

In an effort to advance the understanding of the neurobiology of depression in schizophrenia, we grouped patients with schizophrenia based on their ratings on the 21-item Hamilton Depression Rating Scale. There were 63 patients (35 men, 28 women) in the high (> or = 18) depression group and 81 patients (52 men, 29 women) in the low (< 18) depression group. The groups were compared in demographic, clinical, and eight neuropsychological domains.

The two groups differed in age at onset of illness, severity of delusions, and performance in a single neuropsychological domain: attention. The specific component of impaired attention was vigilance, with poorest performance seen in women with higher depression scores.

The presence of specific attentional impairment associated with depressive symptoms in schizophrenia is consistent with the hypothesis of frontal lobe dysfunction in depression, because these regions have been implicated in attentional processes.