SynopsisAn experiment is described in which depressed patients were asked to recall pleasant or unpleasant experiences from their past life in response to a standard series of stimulus words. The ratio between the time for recall of pleasant and unpleasant experiences was found to fall progressively with increasing severity of depression or of ‘neuroticism’ and to be significantly related to each. Among patients who scored relatively low on depression or neuroticism pleasant memories were recalled more speedily than unpleasant; among those who scored high this relationship was reversed. Possible mechanisms to account for these findings are discussed.

The aetiological factors relevant to the development of post-concussional symptoms are reviewed. From the numerous studies carried out to date, it would appear that both physiogenic and psychogenic influences are important in their genesis. However, where mild-to-moderate injuries are concerned, organic factors are chiefly relevant in the earlier stages, whereas long-continued symptoms are perpetuated by secondary neurotic developments, often of a complex nature.

A signal detection analysis was used in a recognition memory task involving material of varying hedonic tone. Major differences were found between the control and depressed states. Although overall recognition rates were the same, pleasant material was recognised less and unpleasant material more easily by depressives. Neutral material was recognised equally well by both groups. In the depressed state, response biases were altered such that unpleasant material was handled in a preferential way to neutral or pleasant material.

The association between developmental defects of the corpus callosum and major psychiatric disturbance is discussed with a review of published cases. Seven new cases are presented, of which four had clear psychotic symptoms, two receiving a diagnosis of schizophrenia. Of the remainder, one had a developmental disorder affecting social interaction and speech which could be classed as Asperger's syndrome, one had a personality disorder with depressive and conversion symptoms, and the last was an adolescent boy with severe behavioural problems. The difficulties in determining the precise relevance of the callosal anomalies to these clinical manifestations are discussed especially since the prevalence of such anomalies in the population is uncertain. (y Neurol Neurosurg Psychiatry 1993;56:85-93)