The timing of neurodevelopmental abnormality in schizophrenia: an integrative review of the neuroimaging literature

Occipital bending in schizophrenia

OBJECTIVE

To investigate the prevalence of occipital bending (an occipital lobe crossing or twisting across the midline) in subjects with schizophrenia and matched healthy controls.

METHOD

Occipital bending prevalence was investigated in 37 patients with schizophrenia and 44 healthy controls.

RESULTS

Ratings showed that prevalence was nearly three times higher among schizophrenia patients (13/37 [35.1%]) than in control subjects (6/44 [13.6%]). Furthermore, those with schizophrenia had greater normalized gray matter volume but less white matter volume and had larger brain-to-cranial ratio.

CONCLUSION

The results suggest that occipital bending is more prevalent among schizophrenia patients than healthy subjects and that schizophrenia patients have different gray matter-white matter proportions. Although the cause and clinical ramifications of occipital bending are unclear, the results infer that occipital bending may be a marker of psychiatric illness.

Brain abnormalities in schizophrenia

The present study examined, by means of Magnetic Resonance Imaging (MRI), the qualitative brain abnormalities in a group of 58 schizophrenic patients compared to a group of 58 matched control individuals. The possible relationships between these abnormalities and the demographic and clinical features of the participants in the study were also investigated. Schizophrenic patients presented a higher percentage of bland-moderate enlargement of the periencephalic-subarachnoid spaces (p=0.01) and a widespread cerebral atrophy, the latter below the threshold of significance (p=0.06). In the subset of patients with ventricular asymmetry (right larger than left) the age was significantly lower compared to the age of patients without this abnormality (p=0.04). In the subset of patients with cerebellar cisterns enlargement the age as well as the age of onset was higher in comparison to the one of patients without this abnormality (p=0.02; p=0.006). Taking together with previous studies, these findings underline the importance of qualitative assessment of brain morphology in research and clinical evaluation of patients with schizophrenia.

Early detection and treatment of schizophrenia: how early?

OBJECTIVE

Whereas early detection and therapy of schizophrenic psychoses until some time ago concentrated on frank schizophrenia, during the last years some centres have also started to treat patients even before a clear diagnosis could be established. This paper attempts to discuss if and when this is justified in the light of recent research.

METHOD

Mini review of literature.

RESULTS

The rationale for early detection and treatment of schizophrenia is based on several observations: diagnosis and treatment of schizophrenia are often seriously delayed. Consequences of the disease are severe already in the early undiagnosed phase of the disorder and early treatment seems to improve the course of the disease. It can therefore be stated quite safely that patients should be treated as early as possible. However, the question of how early has not been sufficiently answered up to now.

CONCLUSION

We are at the moment in an ethical dilemma between either diagnosing and treating this disorder too late or too early. The only way and prerequisite for solving this dilemma is a more reliable identification of individuals at risk and the beginning disease process.

The catechol-O-methyltransferase polymorphism: relations to the tonic-phasic dopamine hypothesis and neuropsychiatric phenotypes

Diverse phenotypic associations with the catechol-O-methyltransferase (COMT) Val158Met polymorphism have been reported. We suggest that some of the complex effects of this polymorphism be understood from the perspective of the tonic-phasic dopamine (DA) hypothesis. We hypothesize that the COMT Met allele (associated with low enzyme activity) results in increased levels of tonic DA and reciprocal reductions in phasic DA in subcortical regions and increased D1 transmission cortically. This pattern of effects is hypothesized to yield increased stability but decreased flexibility of neural network activation states that underlie important aspects of working memory and executive functions; these effects may be beneficial or detrimental depending on the phenotype, a range of endogenous factors, and environmental exigencies. The literature on phenotypic associations of the COMT Val158Met polymorphism is reviewed, highlighting areas where this hypothesis may have explanatory value, and pointing to possible directions for refinement of relevant phenotypes and experimental evaluation of this hypothesis.