Season of birth variations in the temperament and character inventory of personality in a general population.

BACKGROUND: Since several studies show season of birth variations in morbidity, suicidal behavior and CSF (cerebrospinal fluid) monoamine metabolites, we investigated season of birth variations in personality in the population. METHODS: We analyzed by multiple logistic regressions the Temperament and Character Inventory (TCI) for 2,130 individuals taking part in the Betula prospective random cohort study of Umeå, Sweden. RESULTS: The personality dimensions were correlated significantly with age and gender. We stratified the data according to age, gender and the season of TCI measurement. By the median split in each stratum, a high-value group and a low-value group were obtained for each of the personality dimensions. Those born during February to April were significantly more likely than those born during October to January to have high NS (novelty seeking) among women, particularly the subscale NS2 (impulsiveness vs. reflection), and to have high PS (persistence) among men. Temperament profiles also showed season of birth variations. CONCLUSIONS: We discuss the associations in the literature between personality and the monoamines serotonin and dopamine, and suggest that our results are compatible with a hypothesis of season of birth variation in the monoamine turnover. The personality traits are likely to be influenced by several genetic and environmental factors, one of them being the season of birth.

Season of birth variations in dimensions of functioning evaluated by the diagnostic interview for borderline patients.

In view of recent reports showing that cerebrospinal fluid (CSF) levels of monoamine metabolites exhibit season of birth variations, and that they are also associated with section II (impulse action patterns) of the diagnostic interview for borderline patients (DIB), we analyzed two samples of data to investigate the relationship between the season of birth and the DIB. The first sample comprised 202 patients participating in psychobiological research in Stockholm, and the second sample comprised 130 patients who had committed suicide in Västerbotten in northern Sweden. Those with intermediate score for section II (impulse action patterns) were significantly more likely to have been born during the season October to January in the pooled data, and this tendency persisted in separate analyses for the two samples and for the two diagnostic groups mood disorders and schizophrenia, respectively. Those with high score for section IV (psychosis) were significantly more likely to have been born during February to April in the pooled sample and in the nonschizophrenic group. In the group with schizophrenia, those born during February to April had significantly high scores for section III (affects). These results throw further light on the role of season of birth in suicidology and in psychiatric morbidity.

Variations in CSF monoamine metabolites according to the season of birth.

The cerebrospinal fluid (CSF) concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) as well as their ratios and correlations were analyzed in relation to the season of birth. The sample consisted of 241 drug-free patients participating in psychobiological programs and comprising the DSM-III-R diagnoses of mood, anxiety and adjustment disorders. Significant season-of-birth variations were found even after adjusting for sex, age, height, the diagnostic category and the month of lumbar puncture. Those born during February to April had significantly lower values of 5-HIAA. Values of HVA and of the ratios HVA/5-HIAA and HVA/MHPG were significantly higher for those born during October to January. Correlation coefficients also showed season-of-birth variations. These results may provide an important link for the season-of-birth variations reported for several neuropsychiatric disorders.

CSF monoamine metabolites in relation to the diagnostic interview for borderline patients (DIB).

The cerebrospinal fluid concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol, and their ratios were studied in relation to the Diagnostic Interview for Borderline patients (DIB) evaluated retrospectively from hospital records for a sample of 202 patients participating in psychobiological programs on mood disorders. No correlations with the total DIB score were significant. Patients with borderline personality disorder (BPD) defined by a total DIB score of at least 7 or 6, respectively, did not differ significantly from non-BPD regarding the metabolites. However, for section II (impulse action pattern) of the DIB, those with an intermediate value of the section score had significantly higher levels of 5-HIAA and HVA, suggesting that such higher than normal concentrations may be protective against impulsive or suicidal behavior generated by an underlying psychiatric morbidity due to other risk factors.

Anticipation in unipolar affective disorder.

Anticipation describes an inheritance pattern within a pedigree with an increase in disease severity and/or decrease in age at onset in successive generations. The phenomenon of anticipation has recently been shown to be correlated with the expansion of trinucleotide repeat sequences in a neuromuscular disease, various neurodegenerative disorders and mental retardation. We have studied parent-offspring differences in age at onset and disease severity in 31 pairs with unilineal inheritance of unipolar affective disorder (UPAD). Life-table analyses showed a significant decrease in survival to 1st episode of major depression in the offspring generation compared with the parental generation (P = 0.0007). There was also a significant difference in age at onset (P < 0.001) between parents and offsprings. The offspring generation experienced onset 15.6 years earlier and illness 1.5 x more severe than did the parent generation. Furthermore, there was a significant correlation (P < 0.05) in age at onset between parent and offspring generations. When we excluded pairs where the affected parent has an age of onset greater than the age of the child at the time of ascertainment (i.e., 23 pairs left), there was still a significant (P = 0.02) decrease in age at onset (8.4 years) and 1.5 x more severe disease in the offspring generation. No evidence for specific maternal or paternal inheritance was found. We found evidence of anticipation in 75-80% of this sample of unilineal family pairs of UPAD. Anticipation is, thus, an inheritance pattern in a large group of UPAD which suggests that the expansion of trinucleotide repeat sequences is a possible mode of inheritance in this group of UPAD. The findings of anticipation in this study of families with UPAD and previous findings in families with BPAD suggest that the variable expression of unstable expansions of trinucleotide repeats may turn out to be the basis of the continuum of liability in affective disorders.

Detection of expanded CAG repeats in bipolar affective disorder using the repeat expansion detection (RED) method.

Genetic factors are of major aetiological importance in Bipolar Affective Disorder (BPAD type I and II). The exact mode of inheritance of BPAD is unknown, but the recent demonstration of anticipation suggests that dynamic mutations could be involved in the clinical expression of the disease. We have used the repeat expansion detection (RED) method to test whether the anticipation in BPAD could be explained by the presence of expanded trinucleotide repeat sequences. Using a (CTG)10 oligonucleotide a significantly higher number of expanded CAG repeats were found in the genomic DNA of two independent samples of unrelated BPAD patients of Swedish and Belgian ancestry as compared with normal controls. The difference in repeat number was more consistent if data of the two samples of patients was pooled. In this study a CAG trinucleotide repeat expansion was associated for the first time with a major psychiatric disorder. It is possible that the CAG trinucleotide repeat expansion is involved in the clinical expression of BPAD and that it is the molecular basis explaining the phenomenon of anticipation observed in this disorder.

Anticipation in Swedish families with schizophrenia.

Nineteen parent-offspring pairs obtained from 14 two-generation families with available medical records and diagnosis of schizophrenia were studied to compare the ages of onset of the parent generation with those of the offspring generation. The mean age of onset for the parent generation was 37.3 +/- 6.0 years and for the offspring generation was 20.8 +/- 4.4. The mean difference was thus 16.5 +/- 6.2, suggesting the occurrence of anticipation in schizophrenia (p < 0.001). Although some ascertainment biases (like reduced fertility in early-onset parents or early detection of symptoms in offsprings of affected parents) may partially contribute to the occurrence of anticipation, this study replicates recent reports of anticipation in several neuropsychiatric disorders, some of which have been shown to be associated with unstable expansions of trinucleotide repeats in the genomic DNA.

Anticipation in Swedish families with bipolar affective disorder.

Anticipation describes an inheritance pattern within a pedigree with an increase in disease severity or decrease in age at onset or both in successive generations. The phenomenon of anticipation has recently been shown to be correlated with the expansion of trinucleotide repeat sequences in different disorders. We have studied differences of age at onset and disease severity between two generations in 14 families with unilinear inheritance of bipolar affective disorder (BPAD). There was a significant difference in age at onset (p < 0.008), in episodes per year with (p < 0.006) and without (p < 0.03) lithium treatment, and in total episodes per year (p < 0.002) between generations I and II. Furthermore, there was a highly significant correlation (p < 0.001) in age at onset between generations I and II. No evidence for specific paternal or maternal inheritance was found. We found evidence of anticipation and could rule out ascertainment bias or some other artefact. Anticipation is thus an inheritance pattern in BPAD which suggests that the expansion of trinucleotide repeat sequences is a possible mode of inheritance in BPAD.

Perception of spouse in relation to perception of self by semantic differentials in depressed patients and their spouses.

Several studies have shown correlations between personality types and affective disorders. To investigate the influence on personality assessment of the reporting individual's own schemata according to the cognitive theory of depression, we used an instrument of 29 items of semantic differentials. We obtained responses from 45 patients (18 men, 27 women) upon their recovery and from their spouses. Each of these 90 individuals indicated self-perception on one copy and his or her perception of spouse on another. Factor analysis yielded four factors. Self-perception and perception by spouse were significantly positively correlated for all these factors for the patients and their spouses, indicating lack of schemata influence. Anxiety scores were higher for patients and for women. There was negative correlation for extroversion within couples. Male (but not female) patients showed a negative correlation with their spouses for anxiety.

DNA linkage analysis of X-linked retinoschisis.

Four families with juvenile retionoschisis (RS) have been studied by linkage analysis utilizing eleven polymorphic X-chromosomal markers. The results suggest a close linkage between DXS43, DXS41, and DXS208 and the RS locus at Xp22. The RS locus is distal to the OTC locus, DXS84, and the DMD locus but proximal to DXS85. No recombination events were observed between the RS locus and DXS43 and DXS41. The maximum likelihood estimate of the recombination fraction (theta) was thus zero and the peak lod scores (z) were 4.98 (DXS43) and 4.09 (DXS41). The linkage data suggest that the gene order on Xp is DXS85-(DXS43, RS, DXS41)-DMD-DXS84-OTC.

Tests of gene order from three-locus linkage data.

Exact tests for gene order are derived and compared for three loci using linkage data from phase-known, completely informative marker loci (i.e. parents are heterozygotes with at most one allele identical at each locus), or from triple back-cross matings. A simulation method, based on resampling genotypes of children, is introduced to obtain approximations to the distribution of the test statistics for general mating types in families consisting of children and parents, with or without grandparents, as are used in many studies in human gene mapping. The method is illustrated by an application to linkage data on chromosome 13.

Analysis of fragile X-mental retardation families using flanking polymorphic DNA probes.

Fragile-X mental retardation (FRAX-MR) is one of the more common X-linked disorders affecting 1 in 1,500 newborn males. This disease is characterized by the expression of fragile site in the region q27.3 of the X-chromosome of affected boys when their lymphocytes are cultured in folate deficient medium. In most patients there is macroorchidism postpubertally. The clinical diagnosis of carrier females based on the expression of fragile site in Xq27.3 is usually difficult and sometimes impossible. About half of the carrier females escape diagnosis by this method. Furthermore, prenatal diagnosis is not always feasible. Using Restriction Fragment Length Polymorphism (RFLP) and cloned DNA segments from the region Xq27-Xqter as probes, we have investigated Swedish families with FRAX-MR in three generations. Interesting observations, previously unreported to our knowledge, have been made in some patients and carrier mothers, using one of the probes which is localized to the distal end of Xq. The significance of these findings and the linkage of the disease locus to the different probes used in this study is presented.

On the lod score method in linkage analysis.

Genetic epidemiology deals with the interaction of environmental and genetic determinants in common diseases. Linkage analysis is an important branch of this field. The current practice of claiming linkage between two genetic loci when the maximum lod score z(theta) exceeds 3 has not received theoretical justification, whether considered as a sequential or as a fixed sample size test. Within the framework of significance testing, Wald's (1947) formulae are not applicable to allow this procedure a sequential interpretation. Considered as a fixed sample size test, we find that a chi 2 approximation would instead be very adequate. Since repeated significance testing is performed on linkage data, the nominal significance level should be more stringent for each test than the overall level. Some recent developments in group sequential trials by Pocock (1977) and in repeated significance testing by Woodroofe (1979) seem to indicate that the critical value of the maximum lod score should lie roughly between 0.9 and 3.3, depending on the maximum number of repetitions anticipated, on whether the significance level is desired to be 0.05, 0.01 or 0.001, and on whether the test is derived from a one-sided or a two-sided consideration. In terms of the group sequential approach, if a maximum of twenty repetitions is allowed, if z(theta) greater than log10 A is considered as a one-sided test and assumed to be symmetric when linkage is absent, then the type I error is approximately given by 1/A. We also treat the confidence interval approach for exclusion of unlikely recombination values.