M. Petit

The effects of familiarity and emotional expression on face processing examined by ERPs in patients with schizophrenia

BACKGROUND The main objective of the study was to determine whether patients with schizophrenia are deficient relative to controls in the processing of faces at different levels of familiarity and types of emotion and the stage where such differences may occur. METHODS ERPs based on 18 patients with schizophrenia and 18 controls were compared in a face identification task at three levels of familiarity (unknown, familiar, subjects own) and for three types of emotion (disgust, smiling, neutral). RESULTS The schizophrenic group was less accurate than controls in the face processing, especially for unknown faces and those expressing negative emotions such as disgust. P1 and N170 amplitudes were lower and P1, N170, P250 amplitudes were of slower onset in patients with schizophrenia. N170 and P250 amplitudes were modulated by familiarity and face expression in a different manner in patients than controls. CONCLUSIONS Schizophrenia is associated with a genelarized defect of face processing, both in terms of familiarity and emotional expression, attributable to deficient processing at sensory (P1) and perceptual (N170) stages. These patients appear to have difficulty in encoding the structure of a face and thereby do not evaluate correctly familiarity and emotion.

Saccadic and smooth-pursuit eye movements in deficit and non-deficit schizophrenia

We have analyzed eye movement performances in schizophrenics showing primary negative or deficit symptoms (n=16) and non-deficit schizophrenics (n=55), and compared them with those of controls (n=34) in order to study the relationships between negative symptoms and eye movement abnormalities. Patients were subtyped into deficit and non-deficit subgroups using the Schedule for the Deficit Syndrome. Three oculomotor paradigms were used: smooth pursuit, a reflexive saccade paradigm and an antisaccadic task. The smooth pursuit gain was significantly decreased (and the rate of catch-up saccades increased) in schizophrenics as compared with controls, but no difference was observed between patient groups. In the reflexive saccade paradigm, no difference was found between controls and patients, except for latency in deficit patients. In the antisaccade paradigm, the number of errors and the latency of successful antisaccades were significantly increased in schizophrenics as compared with controls. The latency of successful antisaccades in both directions was significantly increased in deficit patients as compared with non-deficit patients. The latency of rightward successful antisaccades was significantly increased as compared with the latency of leftward antisaccades in deficit patients only. However, when patients were classified into negative and non-negative groups using the PANSS, no difference was found in the antisaccade paradigm. Smooth pursuit impairment does not seem to depend on the primary enduring negative symptoms.In deficit schizophrenics, the abnormalities observed in the antisaccadic task are consistent with prefrontal dysfunction, and may suggest parietal lobe dysfunction as well.

Month of birth in deficit and non-deficit schizophrenic patients

In order to test the hypothesis that an excess of summer births is a risk factor for deficit syndrome, the month of birth was studied in 53 deficit schizophrenic patients compared to 158 non-deficit patients. No significant difference in terms of month of birth or season of birth was observed between deficit and non-deficit patients, suggesting that summer births might not be a risk factor for deficit schizophrenia.

Apolipoprotein E-ε4 frequency in deficit schizophrenia

The apolipoprotein E (ApoE) genotype has been found to affect the expression of several neuropsychiatric disorders. We determined ApoE genotype frequencies and their relationship to primary negative symptoms in 61 non-deficit and 45 deficit schizophrenic patients, and compared them with 98 control subjects. No difference was observed when genotype or allele frequencies were compared between the three groups. Our data do not support a role for ApoE in the phenotypic expression of schizophrenia.

Kleine-Levin syndrome misdiagnosed as schizophrenia.

A 27 year-old man initially considered as a schizophrenic patient was later diagnosed as having Kleine-Levin syndrome.

No pathogenic rearrangement within the DISC 1 gene in psychosis.

A translocation disrupting the DISC 1 gene segregates with schizophrenia and related psychiatric disorders in a large Scottish family. Mutation screening of this gene by routine PCR‐based methods has remained largely negative. We sought to detect rearrangements affecting DISC 1 in 347 individuals meeting the DSM3R criteria for schizophrenia or schizoaffective disorder, 70 subjects with bipolar disorder and 377 psychiatrically healthy controls, but failed to detect any pathological rearrangement.