A haplotype within the DISC1 gene is associated with visual memory functions in families with a high density of schizophrenia

We have previously reported evidence of linkage and association between markers on 1q42 and schizophrenia in a study sample of 498 multiply affected Finnish nuclear families, leading to the recent identification of four significantly associated haplotypes that specifically implicate the Translin-Associated Factor X (TRAX) and Disrupted in Schizophrenia 1 and 2 (DISC1 and DISC2) genes in the genetic etiology of schizophrenia. Previously, the DISC genes were found to be disrupted by a balanced translocation (1;11)(q42.1;q14.3) that cosegregated with schizophrenia and related disorders in a large Scottish pedigree. Interestingly, we also reported earlier suggestive linkage between endophenotypic quantitative traits of visual and verbal memory and microsatellite markers in close proximity to TRAX/DISC, on 1q41. Here, we tested if the identified allelic haplotypes of TRAX/DISC would be associated with visual and/or verbal memory function impairments that are known to aggregate with schizophrenia in families. One haplotype of DISC1, HEP3, displayed association with poorer performance on tests assessing short-term visual memory and attention. Analysis of affected and unaffected offspring separately revealed that both samples contribute to the observed association to visual working memory. These results provide genetic support to the view that the DISC1 gene contributes to sensitivity to schizophrenia and associated disturbances and affects short-term visual memory functions. This finding should stimulate studies aiming at the molecular characterization of how the specific alleles of DISC1 affect the visual memory functions and eventually participates in the development of schizophrenia.

Replication of 1q42 linkage in Finnish schizophrenia pedigrees

Chromosome 1q has been implicated in the etiology of schizophrenia in several independent studies. However, the peak linkage findings have been dispersed over a large chromosomal region, with negative findings in this region also being reported. Our group has previously observed linkage on chromosome 1q42, maximizing within the DISC1 gene, which has also been implied in the etiology of schizophrenia based on functional studies. In the study presented here, we genotyped 300 polymorphic markers on chromosome 1 using a study sample of 70 families with multiple individuals affected with schizophrenia or related conditions, independent of the study samples in our previous reports. We again found evidence for linkage on 1q42 maximizing within the DISC1 gene (rs1000731, lod=2.70). Further, a haplotype containing the most strongly linked markers showed some evidence of association with the disease. This replicates the previous linkage finding in the same region and constitutes supportive evidence for a susceptibility gene in this region.

Time patterns and seasonal mismatch in suicide

OBJECTIVE

Physical time-givers may have a modifying effect on the time patterns of death from suicide.

METHOD

Data on a total of 1397 suicides in Finland over a year were collected using the method of psychological autopsy. We linked versatile information on each individual to meteorological data adjusted for local weather conditions, and to the universal astronomic data.

RESULTS

The number of suicides with seasonal mismatch was greater than the expected in the northernmost region of the country (P = 0.03). The northern location was the most significant predictor of such suicides (P = 0.001). They were associated with the changes in ambient temperature during the preceding day (P < 0.00001), the changes to colder preceding suicides in the spring.

CONCLUSION

Our findings show that mismatch between the changes in ambient temperature and those in the length of day may precede death from suicide in some individuals.

Health care contacts before and after attempted suicide among adolescent and young adult versus older suicide attempters

BACKGROUND

The pattern of all health care contacts among young people before and after attempted suicide is not well documented. Neither is it known if the health care contacts of young suicide attempters differ from those of older suicide attempters. This study investigated the age-related clinical characteristics of suicide attempters and the pattern of their contacts with health care before and after attempted suicide in different age groups, particularly adolescence and young adulthood.

METHOD

All consecutive 1198 suicide attempters treated in hospital emergency rooms in Helsinki between January 1997 and January 1998 were identified and divided into three age groups (15-24 years, 25-39 years, 40 years and over). Data were gathered on all health care contacts 1 year before and after the index attempt.

RESULTS

Although adolescent and young adult suicide attempters suffered from severe mental disorders, a remarkable proportion of them were left without psychiatric consultation and aftercare recommendation following the attempt. Two-thirds of 15-19-year-old male suicide attempters had no treatment contact during the month before the attempt, while a quarter of them were referred to psychiatric consultation and a half had no healthcare contact in the month following the attempt.

CONCLUSIONS

These findings indicate considerable scope for improvement in the assessment of young suicide attempters and their referral to aftercare.

Bipolar disorder susceptibility region on Xq24-q27.1 in Finnish families

Bipolar disorder (BPD) is a common disorder characterized by episodes of mania, hypomania and depression. The genetic background of BPD remains undefined, although several putative loci predisposing to BPD have been identified. We have earlier reported significant evidence of linkage for BPD to chromosome Xq24-q27.1 in an extended pedigree from the late settlement region of the genetically isolated population of Finland. Further, we established a distinct chromosomal haplotype covering a 19 cM region on Xq24-q27.1 co-segregating with the disorder. Here, we have further analyzed this X-chromosomal region using a denser marker map and monitored X-chromosomal haplotypes in a study sample of 41 Finnish bipolar families. Only a fraction of the families provided any evidence of linkage to this region, suggesting that a relatively rare gene predisposing to BPD is enriched in this linked pedigree. The genome-wide scan for BPD predisposing loci in this large pedigree indicated that this particular X-chromosomal region provides the best evidence of linkage genome-wide, suggesting an X-chromosomal gene with a major role for the genetic predisposition of BPD in this family.

Bright-light exposure combined with physical exercise elevates mood

BACKGROUND

Physical exercise alleviates depressive symptoms, as does exposure to bright light, especially in those with seasonal variation. Our objective was to compare the effect of exercise alone or combined with morning bright light on mood and the health-related quality of life in healthy subjects.

METHODS

Study subjects were working-age adults, randomized in two groups (n=80): exercise in bright light (group A), or exercise in normal indoor illumination (group B). Intervention lasted for 8 weeks and questionnaire data on mood and the health-related quality of life were collected at study entry, and at weeks 4 and 8.

RESULTS

Physical exercise both in normal indoor illumination and in bright light was effective at alleviating depressive symptoms. The exercise was significantly more effective at alleviating so-called atypical depressive symptoms when combined with bright-light exposure.

LIMITATIONS

There was no active placebo condition, but a comparative, randomized trial was executed.

CONCLUSIONS

Physical exercise in bright light had a positive effect on mood and health-related quality of life in a sample of healthy, working-age people. Further research is needed to explore the mechanisms of the apparent additive effect of exercise and light.

Major depressive episode among young adults: CIDI-SF versus SCAN consensus diagnoses

BACKGROUND

We aimed to evaluate the diagnostic accuracy of a highly structured diagnostic interview in relation to a semi-structured diagnostic procedure. We compared the World Health Organization Composite International Diagnostic Interview Short Form (CIDI-SF) in diagnosing major depressive episode (MDE) to consensus diagnoses based on the SCAN interview (Schedules for Clinical Assessment in Neuropsychiatry).

METHOD

Subjects comprised a follow-up sample of 239 20-24-year-old former high-school students who were administered the SCAN and immediately thereafter the CIDI-SF. Concordance was estimated for 12-month MDE, using different cut-points of the CIDI-SF and for any affective disorders.

RESULTS

Correspondence between instruments was moderate for MDE (kappa = 0.43, sensitivity 0.71, specificity 0.82), but better for any affective disorder (kappa = 0.60, sensitivity 0.70, specificity 0.90). Most false negatives suffered from their depression as much as those correctly identified by the CIDI-SF. False negativity was mainly due to not endorsing the stem questions of the CIDI-SF. Of the false positives almost half had an affective disorder other than MDE.

CONCLUSIONS

The CIDI-SF seems to function best in identifying a broader category of affective disorders. It could be useful in large-scale community surveys where more extensive psychiatric interviews are not feasible.

Maintenance and manipulation in spatial working memory: dissociations in the prefrontal cortex

Two experiments were conducted to compare thec ries of the functional organization of spatial working memory within the human prefrontal cortex. In Experiment I, memory set size for locations was parametrically varied, allowing for the assessment of BOLD signal across maintenance requirements. In the sec ond experiment, manipulation of spatial information held in working memory was contrasted with simple maintenance of that information. Both experiment evoked significant activity in a distributed spatia working memory network. Although dorsolateral prefrontal activation increased monotonically with memory set size, this region was differentially engaged in task conditions involving explicit manipulation of in ternal representations. Activation in the superior frontal sulcal region was associated with maintenance of spatial information, increasing with memory se size. In contrast, ventrolateral prefrontal activation was present only at the highest memory set size, possibly due to the differential use of organizational strategies with more complex stimuli. These results sup port claims that the dorsolateral prefrontal cortex is involved in the manipulation of internal representa tions and that the superior frontal sulcal region is involved in the maintenance of spatial information but they suggest a complex role for the ventrolatera prefrontal region.

Genome-wide scan in a nationwide study sample of schizophrenia families in Finland reveals susceptibility loci on chromosomes 2q and 5q

We have previously carried out two genome-wide scans in samples of Finns ascertained for schizophrenia from national epidemiological registers. Here, we report data from a third genome scan in a nationwide Finnish schizophrenia study sample of 238 pedigrees with 591 affected individuals. Of the 238 pedigrees, 53 originated from a small internal isolate (IS) on the eastern border of Finland with a well established genealogical history and a small number of founders, who settled in the community 300 years ago. The total study sample of over 1200 individuals were genotyped, using 315 markers. In addition to the previously identified chromosome 1 locus, two new loci were identified on chromosomes 2q and 5q. The highest LOD scores were found in the IS families with marker D2S427 (Z(max) = 4.43) and in the families originating from the late settlement region with marker D5S414 (Z(max) = 3.56). In addition to 1q, 2q and 5q, some evidence for linkage emerged at 4q, 9q and Xp, the regions also suggested by our previous genome scans, whereas, in the nationwide study sample, the region at 7q failed to show further evidence of linkage. The chromosome 5q finding is of particular interest, since several other studies have also shown evidence for linkage in the vicinity of this locus.

Genetic influences on brain structure

Here we report on detailed three-dimensional maps revealing how brain structure is influenced by individual genetic differences. A genetic continuum was detected in which brain structure was increasingly similar in subjects with increasing genetic affinity. Genetic factors significantly influenced cortical structure in Broca's and Wernicke's language areas, as well as frontal brain regions (r2(MZ) > 0.8, p < 0.05). Preliminary correlations were performed suggesting that frontal gray matter differences may be linked to Spearman's g, which measures successful test performance across multiple cognitive domains (p < 0.05). These genetic brain maps reveal how genes determine individual differences, and may shed light on the heritability of cognitive and linguistic skills, as well as genetic liability for diseases that affect the human cortex.

Poststroke depression in acute phase after stroke

We studied factors associated with acute poststroke depression in 100 patients, aged 27-70, 2 weeks after their first clinically significant stroke. Depressive symptoms were relatively common (27% Beck Depression Inventory > or =10), but the prevalence of major depression was only 5.6%. Older patients were most vulnerable to poststroke depression. Patients with left hemisphere lesion had no more depression than other patients, but when the lesion was in the left hemisphere or in the brainstem, stroke severity was associated with depression.

Female homicide offenders have greatly increased mortality from unnatural deaths

The mortality of female homicidal offenders has scarcely been studied. Our aim was to examine the mortality of homicidal women in Finland using a representative nation-wide material. The data consisted of all 132 women who underwent forensic psychiatric examinations after committing homicide or attempted homicide in 1982-1992. We analysed their rate and cause of death during follow-up using standardised mortality ratios (SMRs) and the official classification of death. The mean follow-up time for dead subjects was 7 years (S.D. 4), and for the rest 11 years (S.D. 3). There were 22 observed deaths, the expected value being 1.3 (SMR 17.4). The SMR for unnatural deaths was 226 and for suicides 425. The SMRs for women below 40 years were over 220. In conclusion, homicidal women have an over 200-fold risk of unnatural death, rising to over 400-fold for suicide. This should be taken into consideration in planning discharge programmes for homicidal offenders.

Long-term risk factors for suicide mortality after attempted suicide--findings of a 14-year follow-up study

OBJECTIVE

To determine the risk of suicide over a 14-year follow-up period, and to investigate the long-term risk factors for suicide using survival analysis.

METHOD

Data were collected on all unselected deliberate self-poisoning patients (n=1018) treated during 1983 in the emergency unit of Helsinki University Central Hospital.

RESULTS

By the end of the 14 -year follow-up period 222 (21.7%) of these patients had died. Sixty-eight (6.7%) had committed suicide; 44 (9.2%) men and 24 (4.5%) women. The long-term risk factors for suicide were male sex, previous psychiatric treatment, previous suicide attempts, somatic disease and a self-reported 'wish to die' motive for the index suicide attempt.

CONCLUSION

The essential risk factors for suicide were being male and having previous suicide attempts. In addition, history of earlier psychiatric treatment, presence of somatic disease and genuine intent to die in the index suicide attempt suggest that the long-term risk has remained high for over a decade. The findings emphasize the need for long-term planning and treatment of suicide attempters met in the emergency room of general hospitals.

Regional variation in the incidence of schizophrenia in Finland: a study of birth cohorts born from 1950 to 1969

BACKGROUND

We investigated whether there is regional variation in the incidence of schizophrenia and if so. whether it is caused by urban-rural differences, larger spatial clustering, or both. To control for the effect of migration, we examined regional variation in the incidence according to place of birth.

METHODS

Finnish birth cohorts born from 1950 to 1969 were followed in the National Hospital Discharge Register from 1969 until 1991, and all cases of schizophrenia (ICD-8 or ICD-9 295) were identified (N = 14828). Forty-eight of the 559 municipalities were classified as urban and 25% of the Finnish population lived in these municipalities in 1960. For the analysis of spatial clustering, municipalities were grouped into 57 functional small-areas. We used Poisson regression model with the number of births of individuals who later developed schizophrenia as a response variable, and place of birth (urban/rural), birth cohort (1950-54, 1955-9, 1960-64, and 1965-9), functional small-area units, and sex as response variables.

RESULTS

The incidence was slightly higher among the rural-born in the oldest birth cohort. In the other cohorts, it was higher among the urban-born, and the difference between urban and rural born increased in the youngest cohorts. Significant spatial clustering of schizophrenia was observed in eastern Finland.

CONCLUSIONS

Urban birth is a risk factor for schizophrenia in Finland in cohorts born since 1955. However, genuine spatial clustering of schizophrenia in eastern Finland was also observed, possibly caused by genetic isolation.

Chromosome 1 loci in Finnish schizophrenia families

We have earlier reported evidence for linkage to two regions on chromosome 1q32--q42 in schizophrenia families collected for two separate studies in Finland. Here we report the results of a fine mapping effort aimed at further definition of the chromosomal region of interest using a large, population-based study sample (221 families, 557 affected individuals). Most affecteds (78%) had a DSM-IV schizophrenia diagnosis and the remaining had schizophrenia spectrum disorders. We genotyped a total of 147 microsatellite markers on a wide 45 cM region of chromosome 1q. The results were analyzed separately for families originating from an internal isolate of Finland and for families from the rest of Finland, as well as for all families jointly. We used traditional two-point linkage analysis, SimWalk2 multipoint analysis and a novel gamete-competition association/linkage method. Evidence for linkage was obtained for one locus in the combined sample (Z(max) = 2.71, D1S2709) and in the nuclear families from outside the internal isolate (Z(max) = 3.21, D1S2709). In the families from the internal isolate the strongest evidence for linkage was obtained with markers located 22 cM centromeric from this marker (Z(max) = 2.30, D1S245). Multipoint analysis also indicated these loci. Some evidence for association with several markers was observed using the gamete-competition method. Interestingly, the strongest evidence for linkage in the combined study sample was obtained for marker D1S2709, which is an intragenic marker of the DISC1 gene, previously suggested as a susceptibility gene for schizophrenia. These results are consistent with the presence of susceptibility gene(s) in this chromosomal region, a result also implied in other recent family studies of schizophrenia.