Season of birth and electrodermal unresponsiveness in male schizophrenics

Minimal brain damage and seasonality of birth in schizophrenic disorders

A minimal brain damage examination was carried out in 73 schizophrenic patients divided into three groups according to their season of birth. Results showed no statistically significant difference among groups in the prevalence of neurological soft signs.

Electrodermal orienting response during episodes of schizophrenic illness and remissions: a case study

The aim of the present case study was to examine electrodermal orienting response during periods of acute illness and during remission in a male schizophrenic patient. He was exposed five times to a series of moderately intense tones in a standard orienting habituation paradigm, while skin conductance was recorded. He failed to respond to any of the first two tones and was considered a nonresponder both times when he was acutely symptomatically ill. In contrast, he responded to some of the first tones when he was under treatment and both times when he was tested in remission.

Electrodermal activation in first-episode psychotic patients and their first-degree relatives

We hypothesized that electrodermal deviations evident in patients with schizophrenia would also be present in their biological relatives and examined the specificity of abnormal EDA to schizophrenia patients and their families. One hundred and thirty-five first-episode psychotic patients with either schizophrenia or other psychotic disorders; 104 non-psychiatric comparison subjects; 178 relatives of these subjects; and a comparison group of 61 patients with chronic schizophrenia had their EDA monitored while they listened to auditory stimuli. Electrodermal non-responding, regardless of the nature of the stimulus, was common to all patient groups and tended to run in families. However, non-responding did not differentiate the relatives of the psychotic patients from those of non-psychiatric subjects. Responders in both the chronic and first-episode schizophrenia patients showed an excessively high rate of non-specific fluctuations (NSFs), as did the first-degree relatives of the first-episode patients. Patients with major depression had more NSFs than normal, but significantly so only during one of the tone series. Their relatives, however, had a high NSF rate in both tone series. The results indicate that a high NSF rate may represent a psychophysiological marker of risk for schizophrenia and psychotic depression. Electrodermal non-responding is not specific to schizophrenia and is not likely to be useful as an indicator of genetic risk.

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.

Perinatal characteristics and schizophrenia: electrodermal activity as a mediating link in a vulnerability-stress perspective

Vulnerability-stress models of schizophrenia assert that the disorder results from an interaction between genetic or biologically acquired vulnerability and unfavourable environmental conditions. As our knowledge of early environmental factors for schizophrenia evolves, the question of links between early factors and a development of schizophrenia becomes more important. In this article, we analyse the relationship between obstetrical complications (OCs) and adult schizophrenia and methodological concerns in the search for pre- and perinatal risk factors. We review findings of aberrant electrodermal activity in schizophrenic patients and suggest that OCs may induce insults to cerebral structures that are critically involved in the control of orienting and of autonomic responses.

Seasonality of births in schizophrenia and bipolar disorder: a review of the literature

More than 250 studies, covering 29 Northern and five Southern Hemisphere countries, have been published on the birth seasonality of individuals who develop schizophrenia and/or bipolar disorder. Despite methodological problems, the studies are remarkably consistent in showing a 5-8% winter-spring excess of births for both schizophrenia and mania/bipolar disorder. This seasonal birth excess is also found in schizoaffective disorder (December-March), major depression (March-May), and autism (March) but not in other psychiatric conditions with the possible exceptions of eating disorders and antisocial personality disorder. The seasonal birth pattern also may shift over time. Attempts to correlate the seasonal birth excess with specific features of schizophrenia suggest that winter-spring births are probably related to urban births and to a negative family history. Possible correlations include lesser severity of illness and neurophysiological measures. There appears to be no correlation with gender, social class, race, measurable pregnancy and birth complications, clinical subtypes, or neurological, neuropsychological, or neuroimaging measures. Virtually no correlation studies have been done for bipolar disorder. Regarding the cause of the birth seasonality, statistical artifact and parental procreational habits are unlikely explanations. Seasonal effects of genes, subtle pregnancy and birth complications, light and internal chemistry, toxins, nutrition, temperature/weather, and infectious agents or a combination of these are all viable possibilities.

Season of birth and electroencephalogram power abnormalities in schizophrenia

To determine the association between season of birth and electroencephalogram (EEG) power abnormalities in schizophrenia, this study examined the resting EEGs of 28 winter-born and 81 nonwinter-born schizophrenia patients. Eighteen winter-born and 58 nonwinter-born nonschizophrenic psychosis patients (e.g., bipolar disorder patients with psychotic features), and 97 normal subjects were also studied. Compared to normal subjects, nonwinter-born schizophrenia patients had augmented low-frequency power and diminished alpha band power, but winter-born schizophrenia patients failed to have any EEG power abnormalities. Nonwinter-born nonschizophrenic psychosis patients had the same low-frequency and alpha band power abnormalities as nonwinter-born schizophrenia patients. The winter-born non-schizophrenic psychosis group failed to show any EEG power abnormalities. The results of this study indicate that in psychosis the functional characteristics of the brain vary depending on the season in which a person is born. Low-frequency and alpha band EEG power abnormalities may help distinguish psychosis stemming from a seasonally varying pathogen from psychosis of other etiologies.

No difference found between winter- and non-winter-born schizophrenic cases

The distinction between winter-born (WBS) and non-winter born (NWBS) schizophrenic cases has been proposed as a strategy to identify distinct etiologic subtypes within schizophrenia, the WBS subgroup being a predominantly environmental subtype. The goal of this paper is to empirically test the validity of this strategy by comparing WBS and NWBS groups on a broad array of clinical and biological variables. DSM-III-R schizophrenic, schizoaffective and schizophreniform subjects were comprehensively assessed using (i) the Comprehensive Assessment of Symptoms and History; (ii) a comprehensive neurological exam; (iii) a neuropsychological battery, including IQ and the Continuous Performance Test and (iv) an MRI scanning. The patients were divided into WBS and NWBS, using five alternative sets of definitions of winter birth. These comparisons yielded no differences between the groups on any of the 23 variables. The results suggest that the distinction between winter-born and non-winter-born cases has very limited power to identify distinct schizophrenic subtypes, and that better delineation of the correlates of environmental risk factors in schizophrenia will require a better identification of these factors.

The relationship of the skin conductance and finger pulse amplitude components of the orienting response to season of birth in schizophrenia and depression

Schizophrenia is said to be associated with a modest excess of winter births. We examined relations of season of birth (SOB) to the skin conductance response (SCR) and finger pulse amplitude response (FPAR) components of the orienting response (OR) in 83 schizophrenic patients, 59 depressed patients, and 81 normal controls. SCR-OR nonresponding was more prevalent among depressed patients regardless of SOB, whereas only winter-born schizophrenics showed significantly more frequent electrodermal nonresponding than controls. However, this latter relation was not confirmed with log linear analysis. No other relations of SOB to SCR-OR or FPAR-OR nonresponding were significant. Our data do not support the view that nonresponding in the SCR or FPAR components of the OR is associated with winter birth either in schizophrenia or depression.

Seasonality of birth and ventricular enlargement in chronic schizophrenia

Many studies have established that birth dates during the winter and early spring months are more common in schizophrenic patients than in the general population. It has been hypothesized that children born in winter are more likely to be exposed to environmental factors which could lead to the development of schizophrenia later in life. Another finding of interest has been the demonstration in brain-imaging studies that mild ventricular enlargement is more often found in schizophrenic patients than in healthy control subjects. In the present report, an increased incidence of ventricular enlargement was found in schizophrenic patients born in the winter months. Although the relationship between seasonality of birth and brain abnormalities is unclear, these phenomena could be partly linked.

Postimperative negative variation and skin conductance response in chronic DSM-III-R schizophrenia

The hypothesis was tested that there are relationships between schizophrenic negative or deficit symptoms, the skin conductance nonresponding and an elevated amplitude of the postimperative negative variation (PINV). These variables were recorded in 16 chronic schizophrenics and 10 healthy controls. Clinical symptoms were assessed by the Brief Psychiatric Rating Scale, Scale for the Assessment of Negative Symptoms, Frankfurt Complaint Questionnaire 3 and Chapman Questionnaire. In the patient group we found a significantly elevated PINV at Fz. Surprisingly, only one patient was a skin conductance nonresponder. PINV amplitude at Fz and the number of skin conductance responses to habituation were not correlated with negative or deficit symptoms inclding anhedonia. The hypothesis thus had to be rejected.

Early parental death: relation to electrodermal orienting response and gender in schizophrenia

The aim of the present study was to examine age at parental loss by death and its relation to electrodermal orienting response and sex in schizophrenia. Forty-four DSM-III schizophrenic inpatients were exposed to a series of moderately intense tones in a standard orienting habituation paradigm, while skin conductance was recorded. The twenty-three patients who failed to respond to any of the first two tones were found to be younger when they lost their first parent compared to the 21 responders. When the 44 patients were divided according to sex, the females were found to be younger than the males when parental loss occurred. Finally, when multivariate analyses were performed, it was found that both responding/nonresponding and sex provided almost equally large independent contribution to the prediction of parental loss.

Symptomatology and electrodermal activity as predictors of neuroleptic response in young male schizophrenic inpatients

This study examined whether the response to treatment with neuroleptic medication in 21 schizophrenic patients could be predicted from symptomatology, electrodermal activity, and premorbid adjustment. Positive symptoms and high levels of electrodermal activity were associated with a good response to conventional neuroleptic drugs. However, multivariate analysis indicated that symptomatology was the only independent predictor of treatment response.

Season of birth and electrodermal activity in functional psychoses

The present study examined the association between electrodermal activity (EDA) and season of birth in a sample of first-episode patients with schizophrenia, schizophreniform disorder, and affective disorder with psychotic features, and in a normal control group. Patients with schizophrenia who were born during the season of excess risk (January-April) were less responsive than those born during other times of the year. They had lower skin-conductance levels and fewer skin-conductance responses. No such effects were found in patients with schizophreniform or affective disorder, or in the normal subjects. When compared with the control group, winter-born schizophrenics showed significantly more evidence of hyporesponsivity. In contrast, nonwinter-born patients did not differ from normal subjects in skin-conductance level or number of skin-conductance responses. Schizophreniform patients born during the other seasons of the year were more likely to be hyporesponsive. The above results provide supporting evidence for the validity of the season of birth phenomenon. We hypothesize that a viral infection, or some other perinatal complication associated with winter and early spring births, leads to temporal lobe damage and consequent dysregulation of electrodermal activity in patients with schizophrenia.

Electrodermal orienting response, maternal age, and season of birth in schizophrenia

Consistent with earlier research, male schizophrenic patients born during the season of excess risk for schizophrenia (January-April) showed significantly lower electrodermal responsivity than controls born during the season of excess risk, and patients and controls born during the season not associated with increased risk (May-December). No support for maternal age as an explanation for the season-of-birth effect was found.