These results seem to confirm the role of COMT genotype in the modulation of executive functions related to frontal lobe function in healthy individuals but not in schizophrenia patients.
A neuropsychological etiology has been suggested for lack of insight in schizophrenia patients, mainly based on frontal, right parietal, right hemisphere, or diffuse cerebral dysfunctions. The aim of this study ws to investigate the neuropsychological pathogeny of lack of insight in schizophrenia patients. We examined a sample of 40 DSM-III-R schizophrenia inpatients admitted because of a recrudescence of symptoms. Schizophrenic symptoms were evaluated through the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms. Neurologic explorations included an assessment of frontal neurologic signs, abnormal involuntary movements, and soft neurologic signs. Lack of insight was assessed through three items from the Manual for the Assessment and Documentation of Psychopathology (AMDP). A global index from these three items (lack of feeling ill, lack of insight, and uncooperativeness) was obtained. A neuropsychological battery composed of tests involving many functional areas of the brain was used. No correlation between bad performance and lack of insight was found on any test. On the contrary, lack of insight was associated with better performance on immediate verbal, immediate visual, and delayed visual memory tasks. Moreover, the three components of lack of insight were extracted as an independent factor when they were included together with the positive and negative symptoms, neurologic abnormalities (frontal and soft neurologic signs, and abnormal movements), and a global measure of cognitive performance. The results of the study do not support the neuropsychological hypothesis of lack of insight.(ABSTRACT TRUNCATED AT 250 WORDS)
A study was carried out on a group of 95 schizophrenic patients (DSM-III-R criteria) under the age of 35, 23 of whom were cannabis abusers in the past year. The objective of the study was to evaluate the effect of cannabis on positive and negative schizophrenic symptoms, evaluated using Andreasen's Scales for the Assessment of Positive and Negative Symptoms (SAPS and SANS). There were no statistically significant differences between the groups on the SAPS; the group of cannabis abusers had higher scores except for the delusions subscale. On the SANS nonabusers scored higher, with a significant difference on the alogia subscale. The results suggest that the consumption of cannabis by schizophrenic patients could attenuate negative symptoms, which would support the self-medication hypothesis of cannabis abuse.
Prevalence and correlates of primary motor abnormalities in schizophrenia are presently ill defined. This study was aimed at examining the prevalence, syndromic structure, external correlates, and response to antipsychotic medication of a broad array of primary motor abnormalities. Two-hundred antipsychotic-naive patients with schizophrenia spectrum disorders were examined for motor abnormalities using the Modified Rogers Scale. Thirty-one motor signs were subjected to factor analysis, and the resulting factors examined for association with a number of risk factors, clinical and psychopathological variables. One-hundred and eighty-nine patients were reassessed for motor abnormalities after completing a 4-week trial with antipsychotic medication. Prevalence rates for at least one motor sign and syndrome at baseline were 66% and 40%, respectively. Motor signs clustered together into seven clinically interpretable factors: abnormal involuntary movements, hypokinesia, retarded catatonia, echo-phenomena, excited catatonia, catalepsy, and parkinsonism. All motor domains but parkinsonism were inter-related. Abnormal involuntary movements were associated with variables indicating both neurodevelopmental dysfunction and illness severity, and most motor domains were closely related to negative or disorganization symptoms. Change scores in motor domains after treatment with antipsychotic medication indicated improvement for abnormal involuntary movements, hypokinesia, retarded catatonia, excited catatonia and echophenomena, and worsening for parkinsonism. It is concluded that primary motor dysfunction is a prevalent and heterogeneous condition of schizophrenia. Motor abnormalities segregate into various syndromes, which have different clinical correlates and a differential response pattern to antipsychotic medication. It is hypothesized that the existence of a differential dopaminergic dysfunction in the nigroestriatal circuitry is responsible for the generation of those motor domains that improve and worsen with antipsychotic drugs.
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