Sex Differences In Schizophrenia Research Articles

An animal model for the effects of estradiol on dopamine-mediated behavior: Implications for sex differences in schizophrenia

Schizophrenic women have been consistently found to have a later age of onset and a less severe clinical course of illness as compared with schizophrenic men. Because these differences are not explained by diagnostic artifacts or sociocultural factors, we tested the hypothesis that they are determined by the influence of the gonadal hormones testosterone and estradiol on dopaminergic (DA) neurotransmission. We used animal models in which the effects of the hormones on behavioral changes induced by the DA antagonist haloperidol (catalepsy) and by the DA agonist apomorphine (oral stereotypies, grooming and sitting behavior) were investigated in neonatal and in adult treated rats. No consistent effects of testosterone were observed. Estradiol significantly reduced the behavioral changes induced by both haloperidol and apomorphine, and this effect was more pronouced in neonatally treated animals. These results suggest a downward regulation of DA neurotransmission by estradiol, which is supported by the results of 3H-sulpiride binding determinations in brain homogenates from the same animals: estradiol caused a 2.8-fold reduction of DA receptor affinity to sulpiride. Our findings suggest that estradiol might act as a protective modulator in schizophrenia by enhancing the vulnerability threshold for psychosis through the downward regulation of DA neurotransmission. Such mechanism could explain, at least in part, the later onset and the more favorable course of schizophrenia in female patients.

The Effect of Culture on the Sex Differences in Schizophrenia

Cultural influences on sex differences in clinical characteristics and symptomatology of schizophrenia were studied among 369 schizophrenic patients from the United States and Turkey. Male schizophrenics were more likely to be single, and were younger than female schizophrenics at onset of symptoms and when first diagnosed, treated and hospitalised in both cultures. Turkish male and female schizophrenics were more ambivalent, inappropriate, "silly", euphoric, depersonalised, dissociated, mute, conceptually disorganised, and exhibiting more flight of ideas and thought than American male and female schizophrenics. Irrelevant thought and stereotypic behaviour were most severe in Turkish male and American female schizophrenics. Hallucinatory behaviour was most intense in Turkish separated, divorced, or widowed female schizophrenics and American married male schizophrenics. Turkish married female and Turkish separated, divorced, or widowed male schizophrenics were most disoriented. Turkish single female schizophrenics were most mute. Turkish separated, divorced, or widowed male schizophrenics showed most intense stupor behaviour.

Temporal Lobe Asymmetries as the Key to the Etiology of Schizophrenia

With evidence that determinants of psychosis are present early and influence brain development, and in the absence of a significant environmental contribution, schizophrenia may be regarded as a genetic encephalopathy. Morphological abnormalities are particularly apparent in the temporal lobe and on the left side of the brain, and in a number of studies significant diagnosis x side interactions have been detected. Such interactions suggest an intimate relationship between the disease process and the mechanisms that determine asymmetrical brain development. These mechanisms presumably relate to the human capacity for speech and communication, and they may have played a critical role in the evolution of the human brain. A candidate locus for an asymmetry determinant and the psychosis gene within the exchange region of the sex chromosomes is proposed. Some sex differences in schizophrenia (e.g., with respect to age of onset and brain structure) may relate to subtle differences in the rate of asymmetry development in the two sexes.

Implications of Olfactory Agnosia for Understanding Sex Differences in Schizophrenia

In our studies, 50 percent of the male patients with schizophrenia have an olfactory agnosia. This finding is of interest because the olfactory neuroanatomical network involves brain regions found to be abnormal in patients with schizophrenia, and this olfactory deficit appears to be sex dependent. This article reviews conceptual models for assessing olfactory function, describes the neuroanatomical structures involved, and reviews the findings of olfactory performance in patients with neurological dysfunction. The findings are then integrated with neuropathological studies of patients with schizophrenia. Finally, as there is increasing evidence for a sex difference in patients with schizophrenia, a model is suggested to account for these differences based on neuro-developmental and latent lesion hypotheses.

Sex differences in schizophrenia

Sex differences in schizophrenia

Sex differences in schizophrenia

Sex differences in schizophrenia

Sex differences in schizophrenia: Timing or subtypes?

Sex differences in schizophrenia: Timing or subtypes?

Sex differences in schizophrenia: Timing or subtypes?

Sex differences in schizophrenia: Timing or subtypes?

Sex Differences in Schizophrenia: A Commentary*

A critique is offered of Samuels' article suggesting that reported sex differences in concordance rates for schizophrenia are either methodological artifacts or a function of sociological processes. Evidence of sex differences in age of onset, clinical expression, concordance rates among primary relatives, and premorbid competence is cited. Finally, it is concluded that sex differences in schizophrenia offer important clues to the development of the disorder and should be considered in future theories of schizophrenia.