Schizophrenics have consistently been found to be born with unusually high frequency in the early months of the calendar year. A previous study found significantly more schizophrenics to be born following warmer as contrasted with cooler summers, thus suggesting that summer temperature or a correlate of summer temperature may be an effective factor in the season of birth schizophrenia relationship. The current study re-tested the warmer vs. cooler summer finding, using both a local sample (N = 301) and a nationwide sample of Swedish schizophrenics (N = 13,440), each sample showing increased frequency of births in the early months of the year. In order to localize the possible effects of temperature to a more specific gestational period, the schizophrenics in each sample were further divided into sub-groups based upon which trimester of gestation likely occurred during the summer prior to the birth. The 71 years (1876-1946) during which the patients were born rank-ordered by mean summer temperature at representative geographical locations, and the rank-orders of years were divided into temperature quartiles. The rates of births for the total patient groups and the trimester sub-groups among both samples showed no positive linear or systematic relationship to temperature during the previous summer. Even the warmest among the 71 years were not followed by increased rates of births of schizophrenics. The results of the study did not corroborate the earlier finding.
A study was conducted in Sweden in 1989-1992 to evaluate differences in quality of life (QL) in consecutive male and female patients after acute myocardial infarction (AMI), coronary artery by-pass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA). Somatic and psychological dimensions of QL were assessed by self-administered questionnaire in patients one month (n = 376) and one year (n = 349) after the cardiac event. Normal controls (n = 88) were used for comparison. Differences between gender groups, as well as between study patients and controls in somatic and psychological dimensions of QL were studied. Patients were shown to experience poorer QL when compared with demographically similar controls, especially at the one-month assessment. Female patients had poorer QL after one month (in general health, feeling of arrythmia, anxiety, depression, self-esteem, experience of sex life) and after one year (general health, anxiety, depression) compared with male patients. In all dimensions of QL a proportion of patients (19-45%) experienced a decrease in QL from the one-month to the one-year assessment occasion. Healthcare workers concerned with secondary prevention must be aware that QL differs between male and female patients in several dimensions after a cardiac event. These findings should be taken into account in the clinical management of patients, particularly for female patients who may need special attention.
Pre- and perinatal adversities may increase the risk for schizophrenia and bipolar disorder. Hypoxia-related obstetric complications (OCs) are associated with brain anatomical abnormalities in schizophrenia, but their association with brain anatomy variation in bipolar disorder is unknown.
Magnetic resonance imaging brain scans, clinical examinations and data from the Medical Birth Registry of Norway were obtained for 219 adults, including 79 patients with a DSM-IV diagnosis of bipolar disorder (age 29.4 years, s.d. = 11.8 years, 39% male) and 140 healthy controls (age 30.8 years, s.d. = 12.0 years, 53% male). Severe hypoxia-related OCs throughout pregnancy/birth and perinatal asphyxia were each studied in relation to a priori selected brain volumes (hippocampus, lateral ventricles and amygdala, obtained with FreeSurfer), using linear regression models covarying for age, sex, medication use and intracranial volume. Multiple comparison adjustment was applied.
Perinatal asphyxia was associated with smaller left amygdala volume (t = -2.59, p = 0.012) in bipolar disorder patients, but not in healthy controls. Patients with psychotic bipolar disorder showed distinct associations between perinatal asphyxia and smaller left amygdala volume (t = -2.69, p = 0.010), whereas patients with non-psychotic bipolar disorder showed smaller right hippocampal volumes related to both perinatal asphyxia (t = -2.60, p = 0.015) and severe OCs (t = -3.25, p = 0.003). No associations between asphyxia or severe OCs and the lateral ventricles were found.
Pre- and perinatal hypoxia-related OCs are related to brain morphometry in bipolar disorder in adulthood, with specific patterns in patients with psychotic versus non-psychotic illness.
Many studies have shown schizophrenics to be born with unusual frequency in the period January-April, and one interpretation of this seasonality of birth is that the parents of schizophrenics have an unusually strong general tendency to conceive offspring who will be born in January-April. This parental conception habits interpretation may be tested by studying whether the siblings of schizophrenics are also born with increased frequency in January-April. The present study investigated the season of birth of 288 full siblings and 44 half-siblings in 91 families of male schizophrenics. Approximately 5% of the siblings were known to be schizophrenic; with the schizophrenic siblings excluded from the analyses, the full siblings showed a birth pattern much closer (nonsignificant) to that of the schizophrenics than to that of the general population. Half-siblings showed January-April birth rates at or below the population level. Although the mechanisms responsible for the current results still remain unclear, the study suggests that seasonality of births of schizophrenics may be related to the parents' conception habits as well as to an etiological or triggering effect on the development of schizophrenia in the offspring.