The ageing brain, neuroleptic drugs and the enigma of schizophrenia

CT and MRI Abnormalities in Schizophrenia: The New Developmental Biology of Psychosis?

Despite more than a decade of studies, biological psychiatry has yet to satisfactorily resolve the issue of whether new brain imaging technologies reliably indicate the presence of abnormal cerebral morphology in schizophrenia. The present Perspective offers an alternative view on this topic, as a counter-point to one previously offered in the Journal. It addresses several of the methodological problems inherent to such studies, and evaluates some of the more recent aspects of the literature. Those structural abnormalities which have been reported in schizophrenia appear most readily explicable as a consequence of neurodevelopmental anomalies.

From an animal model of an attentional deficit towards new insights into the pathophysiology of schizophrenia

The paper presents an animal model of schizophrenic-like attentional deficit, consisting of an inability to ignore irrelevant stimuli. It is based on the paradigm of latent inhibition (LI), in which animals learn to ignore repeatedly presented stimuli not followed by meaningful consequences. In a series of experiments it was demonstrated that the capacity to ignore irrelevant stimuli is lost in rats treated with systemic or intra-accumbens injections of amphetamine, in normal volunteers given amphetamine, in high "psychosis-prone" persons, in acute schizophrenic patients and in untreated male adult rats that were raised until weaning under conditions of extremely restricted stimulation. In addition, LI is lost following the disruption of the hippocampal input to the nucleus accumbens. In all of the above conditions tested for antagonism by anti-psychotic drugs a loss of LI is reversed. On the basis of these results we propose an animal model which accommodates a neurodevelopmental dysfunction, hippocampal pathology, mesolimbic DA overactivity, vulnerability to stress, and gender differences, all of which have been postulated as factors in the pathophysiology of schizophrenia.

Abnormalities of Cerebral Structure in Schizophrenia on Magnetic Resonance Imaging: Interpretation in Relation to the Neurodevelopmental Hypothesis

The nature of abnormalities of cerebral structure evident in schizophrenia on magnetic resonance imaging is considered in relation to the neurodevelopmental hypothesis of the disorder. While schizophrenic patients showed increased ventricular volume, the extent of increase with age was comparable with that evident in controls and was unrelated to duration of illness. Conversely, cortical atrophy was evident only in patients, and this increased markedly with age and duration of illness. Such findings could be suggestive of two distinct pathophysiological processes in schizophrenia, but a schema for their reconciliation with the neurodevelopmental hypothesis is elaborated.

Obstetric complications, the putative familial-sporadic distinction, and tardive dyskinesia in schizophrenia

Obstetric complications were more common in the histories of those schizophrenic outpatients without a family history of psychiatric disorder, and were associated with an earlier onset of their illness. Those patients with tardive dyskinesia were more likely to have a family history of psychiatric disorder, less likely to have experienced obstetric complications, and showed greater cognitive deficit. Obstetric complications should be considered in juxtaposition with genetic factors in evaluating the putative familial-sporadic distinction in schizophrenia. Additionally, familial/genetic factors appears to contribute to vulnerability to tardive dyskinesia.

Sight and insight: regional cerebral metabolic activity in schizophrenia visualised by positron emission tomography, and competing neurodevelopmental perspectives

Over the past several years there has emerged a family of highly sophisticated but technically complex procedures for the visualisation of a range of cerebral functions in living man (Andreasen, 1988). The images they produce are so beguiling not just because of their potential to give new insights into the pathophysiology and treatment of major psychiatric disorders, but because they convey information through a quite fundamental modality: people are only convinced by what they can see. However, initial applications of such new technology have appeared just as likely to generate new questions and contradictions as to provide answers to current issues. This is readily illustrated by recent studies on the imaging of brain dopamine receptors in schizophrenic patients by positron emission tomography (PET) (see Waddington, 1989a).

Obstetric complications in schizophrenia and the validity of maternal recall

The significance of the excess of obstetric complications which appears to characterize the histories of schizophrenic patients is critically dependent on the validity of the source of obstetric information, especially when this is obtained by maternal recall. Twenty-one biological mothers of 17 schizophrenic and four other patients were interviewed for their recollections of individual events characterizing the pregnancy and delivery relating to each patient. These were then compared with those events documented in maternity hospital records. Only in two of the 21 instances (9.5%) were inconsistencies of detail apparent which would have affected the designation of the relevant patient as having, or as not having, experienced major obstetric complication(s). It is concluded that maternal recall can be a surprisingly accurate source of obstetric information in relation to research on schizophrenia.

Sight and insight: brain dopamine receptor occupancy by neuroleptics visualised in living schizophrenic patients by positron emission tomography

There can be few more impressive sights in contemporary neuroscience and biological psychiatry than the imaging of neurotransmitter receptors in the brains of living human subjects by positron emission tomography (PET; Sedvall et al, 1986). How has such technology advanced our understanding of the pathophysiology and/or treatment of major psychiatric disorders?