PubMed Health⌕ Search

Biomedical subjects

Timo Partonen

Publications and source records attributed to Timo Partonen.

At least 37 records · Page 2Linked to original sources
PubMed2004

Clinical phenotype of schizophrenia in a Finnish isolate.

We identified all cases in Finland (population of 5 million) with a diagnosis of schizophrenia born between 1940 and 1969, using four national computerised registers with high reliability. A sample of 397 families was identified in a genetically homogeneous internal isolate (population of 18,000) in northeastern Finland with high prevalence for schizophrenia and an LOD score of 3.8 in chromosome 1. Our aim was to examine with Operational Criteria Checklist for Psychotic Illness (OCCPI) factor analysis the psychotic and affective signs and symptoms of schizophrenia in this genetically homogeneous population, and compare them with findings from individuals with schizophrenia from multiplex families from the whole country. After collecting all original case notes, we made DSM-IV consensus diagnoses and completed OCCPI ratings on a lifetime basis. For the factor analysis, we accepted 190 patients with a diagnosis of schizophrenia. In addition, 466 schizophrenia patients from 147 multiplex families from the whole country were included in the analysis. The OCCPI factor analysis resulted in four factors: "delusions and hallucinations" and "negative" factors, plus two affective ("manic" and "depressive") factors. We compared the pattern of symptoms among three patient groups: isolate patients who were the only affected individuals in their family, isolate patients who had affected family members, and patients from the whole country with affected family members. We found no clear differences among these groups. However, there were significant differences in the frequency of individual OCCPI items between the study groups. Findings in this schizophrenia OCCPI phenotype study suggest that the clinical picture of schizophrenia in a genetically isolated and homogeneous population closely resembles our nationwide findings in Finland.

Alleles↗
PubMed2004

Seasonal affective disorder and the G-protein beta-3-subunit C825T polymorphism.

BACKGROUND: Guanine nucleotide-binding proteins (G-proteins) have been implicated in affective disorders, with reports of altered signal transduction and G-protein levels. Association with seasonal affective disorder (SAD) has been found for the higher activity T-allele of the G-protein beta-3-subunit C825T polymorphism. METHODS: European SAD patients (n = 159) and matched controls (n = 159) were genotyped for the C825T. Seasonality and diurnal preference were investigated in subsets of the material (n = 177 and 92, respectively). RESULTS: We found no association between C825T and SAD (chi(2) =.09, p =.96) or seasonality (F = 1.76, p =.18). There was some evidence for an effect on diurnal preference but only in the control group (n = 46, t = -2.8, Bonferroni corrected p =.045). CONCLUSIONS: These results suggest that the G-protein beta-3-subunit 825 T-allele does not play a major role in susceptibility to seasonal affective disorder in the population studied.

Alleles↗
PubMed2004

Cyclic time patterns of death from suicide in northern Finland.

BACKGROUND: Time patterns of suicide have been attributed not only to social and psychological factors but also to direct geophysical effects. Seasonal variations in day length and temperature seem likely to contribute to the timing of the suicide process. METHODS: We analysed all suicides (n=1658) committed in a northern province of Finland during a period of 153 months. Daily data on the number of suicides, local weather conditions and geomagnetic storms were compiled and modelled with Poisson regression using the province population as the denominator, and with the means of harmonic series for seasonal variation. Time series analysis of monthly numbers of suicides was carried out using the seasonal-trend decomposition procedure based on loess. RESULTS: Marked fluctuations in the number of suicides occurred during the study period (P=0.01). There was significant seasonal variation in death from suicide (P=0.01), but analysis of the meteorological data showed no evidence of effect on the risk of suicide. LIMITATIONS: Assessment of mental disorder or alcohol consumption was missing, since only data derived from death certificate was available for each case. CONCLUSIONS: The seasonal effect was significant, but remained modest compared to sex and age as risk factors for suicide. Preventive measures need to be tailored according to time of the year.

Adult↗
PubMed2004

Analysis of the seasonal pattern in suicide.

BACKGROUND: Suicide has been attributed to social and psychological factors but also to geophysical effects. Of the latter, changes in solar radiation and geomagnetic activities may contribute to the frequency and the seasonal pattern of suicides. METHODS: We studied with a population-based, nationwide analysis all the individuals who committed suicide (n=27,469) in Finland during the period of 1979 to 1999. The daily data on the number of suicides, and the mean and maximum levels of geomagnetic activity were compiled and modelled with Poisson regression using the number of inhabitants in each province as the denominator. Time series analysis of monthly numbers of suicides was carried out using a seasonal-trend decomposition procedure. RESULTS: There was a strong seasonal effect on suicide occurrence (P<0.00001), the risk of suicide being greatest in spring. The seasonal effect was most pronounced when the number of suicides was relatively low. High levels of solar radiation activity were associated with the increased risk of suicide (P=0.00001), but the effect of geomagnetic activity was weak. LIMITATIONS: No individual data on alcohol consumption or mental disorders were available. CONCLUSIONS: Suicide occurrence varies markedly by season and needs attention where prevention is concerned.

Cosmic Radiation↗
PubMed2004

High concordance of bipolar I disorder in a nationwide sample of twins.

OBJECTIVE: The few studies of bipolar I disorder in twins have consistently emphasized the genetic contribution to disease liability. The authors report what appears to be the first twin study of bipolar I disorder involving a population-based twin sample, in which the diagnoses were made by using structured, personal interviews. METHOD: All Finnish same-sex twins (N=19,124) born from 1940 to 1957 were screened for a diagnosis of bipolar I disorder as recorded in the National Hospital Discharge Register between 1969 and 1991 or self-reported in surveys of the Finnish Twin Cohort in 1975, 1981, and 1990. Thirty-eight pairs were thereby identified and invited to participate in the study; the participation rate was 68%. Lifetime diagnoses were made by using the Structured Clinical Interview for DSM-IV. The authors calculated probandwise and pairwise concordances and correlations in liability and applied biometrical model fitting. RESULTS: The probandwise concordance rates were 0.43 (95% CI=0.10 to 0.82) for monozygotic twins and 0.06 (95% CI=0.00 to 0.27) for dizygotic twins. The correlations in liability were 0.85 and 0.41, respectively. The model with no familial transmission was rejected. The best-fitting model was the one in which genetic and specific environmental factors explained the variance in liability, with a heritability estimate of 0.93 (95% CI=0.69 to 1.00). CONCLUSIONS: The high heritability of bipolar disorder was demonstrated in a nationwide population-based twin sample assessed with structured personal interviews.

Adult↗
PubMed2004

Is low dietary intake of omega-3 fatty acids associated with depression?

OBJECTIVE: This study examined the association between the dietary intake of omega-3 fatty acids and low mood, major depression, and suicide. METHOD: A total of 29,133 men ages 50 to 69 years participated in a population-based trial in Finland. The intake of fatty acids and fish consumption were calculated from a diet history questionnaire. Self-reported depressed mood was recorded three times annually, data on hospital treatments due to a major depressive disorder were derived from the National Hospital Discharge Register, and suicides were identified from death certificates. RESULTS: There were no associations between the dietary intake of omega-3 fatty acids or fish consumption and depressed mood, major depressive episodes, or suicide. CONCLUSIONS: Dietary intake of omega-3 fatty acids showed no association with low mood level.

Aged↗
PubMed2004

Age at onset and cognitive functioning in schizophrenia.

BACKGROUND: Impairments in cognitive functioning are common in schizophrenia, and the degree of impairment may be associated with the individual's age at onset of the disorder. AIMS: To examine the effect of age at onset on cognitive functioning using the California Verbal Learning Test, sub-tests from the Wechsler Memory Scale-Revised and sub-scales from the Wechsler Adult Intelligence Scale-Revised among families with schizophrenia. METHOD: The effect of age at onset on cognitive function in 237 people with schizophrenia from a population-based sample was examined using linear mixed effects models with family as the random effect, and age, gender, chronicity of the illness and number of affected first-degree relatives as fixed effects. RESULTS: Impairment in verbal learning and memory was associated with earlier disease onset. No association was found for working memory or IQ. CONCLUSIONS: In patients with early-onset schizophrenia, verbal memory functions in particular should be taken into account in neuropsychological evaluation and efforts at remediation.

Age of Onset↗
PubMed2003

Reduced left hemispheric white matter volume in twins with bipolar I disorder.

BACKGROUND: Although the heritability of bipolar I disorder (BPI) is high, few magnetic resonance imaging (MRI) studies of siblings of bipolar patients exist. We performed MRI brain scans on a nationwide sample of twins with BPI, as well as on their co-twins and a demographically balanced sample of control twin subjects, to detect any structural alterations related to the disorder and to the increased genetic risk. METHODS: The National Hospital Discharge Register, National Population Register, and Finnish Twin Cohorts were used to identify bipolar twins. Structured diagnostic interviews and MRI scans were obtained for 24 twins with BPI, 15 healthy co-twins, and 27 control twin subjects. RESULTS: Patients and co-twins showed a significant decrease in left hemispheric white matter volume. The disparity in patients was -16.1 cm(3) (95% confidence interval [CI] -26.6, -5.6) and in co-twins -11.3 cm(3) (95% CI -22.1, -0.4) compared with control twin subjects. No gray matter decrease was seen in patients or co-twins. CONCLUSIONS: The results of this first large-scale MRI study of twins with BPI, their co-twins, and appropriate control twin subjects, suggest that alterations of the left hemisphere white matter in BPI may reflect genetic factors predisposing to the disorder.

Adult↗
PubMed2003

Effect of simulated dawn on quality of sleep--a community-based trial.

BACKGROUND: Morning light exposure administered as simulated dawn looks a promising method to treat Seasonal Affective Disorder, but it may moreover help with resetting the inaccurate organisation of body clock functions relative to sleep occurring in winter among people in general. Disturbances in sleep patterns are common and may compromise wellbeing even in the short term. Our hypothesis was that simulated dawn could improve the subjective quality of sleep during winter. METHODS: A community-based trial with 100 volunteer subjects provided with dawn simulators. Study period lasted for eight weeks, and subjects used the dawn simulators for two weeks at a time, each subject acting as his own control (ABAB-design). Main outcome measure was subjective quality of sleep recorded each morning with Groningen Sleep Quality Scale. RESULTS: 77 subjects completed the trial. Quality of sleep improved while subjects were using dawn simulator-devices (p = 0.001). The treatment became beneficial after six days' use of dawn simulator, but the effect did not last after the use was ceased. CONCLUSION: Dawn simulation may help to improve the subjective quality of sleep, but the benefits are modest. Further research is needed to verify these findings and to elucidate the mechanism by which dawn simulation acts on the sleep-wake pattern.

Adolescent↗
PubMed2003

Haplotype transmission analysis provides evidence of association for DISC1 to schizophrenia and suggests sex-dependent effects.

We have previously reported a linkage peak on 1q42 in a Finnish schizophrenia sample. In this study we genotyped 28 single nucleotide polymorphisms (SNPs) from 1q42 covering the three candidate genes TRAX, DISC1 and DISC2, using a study sample of 458 Finnish families ascertained for schizophrenia. Two-point and haplotype association analysis revealed a significant region of interest within the DISC1 gene. A common haplotype (HEP3) was observed to be significantly under-transmitted to affected individuals (P=0.0031). HEP3 represents a two SNP haplotype spanning from intron 1 to exon 2 of DISC1. This haplotype also displayed sex differences in transmission distortion, the under-transmission being significant only to affected females (P=0.00024). Three other regions of interest were observed in the TRAX and DISC genes. However, analysis of only those families with complete genotype information specifically highlights the HEP3 haplotype as a true observation. The finding of a common under-transmitted SNP haplotype might imply that this particular allele offers some protection from the development of schizophrenia. Analysis of component-traits of schizophrenia, derived from the Operational Criteria Checklist of Psychotic Illness (OCCPI), displayed association of HEP3 to features of the general phenotype of schizophrenia, including traits representing delusions, hallucinations and negative symptoms. This study provides further evidence for the hypothesis that the DISC1 gene is involved in the aetiology of schizophrenia, and implies a putative sex difference for the effect of the gene. Our findings would also encourage more detailed analyses of the effect of DISC1 on the component-traits of schizophrenia.

Female↗
PubMed2003

Familial loading associates with impairment in visual span among healthy siblings of schizophrenia patients.

BACKGROUND: The effect of familial loading on neurocognitive deficits in relatives of schizophrenia patients has been detected in family and twin studies. The present study examined this effect among healthy siblings of schizophrenia patients in a Finnish isolate with high prevalence of schizophrenia. METHODS: We assessed performance in verbal and visual span tasks, in tests measuring intelligence, and in declarative verbal memory and learning tasks in 31 and 67 healthy siblings from families with one schizophrenia patient, or with two or more patients, respectively. The differences between the groups were tested using linear mixed effects models. RESULTS: An effect of familial loading was detected in the backward visual span task, measuring immediate visual memory with requirements from the visual domain of working memory. In this task, the healthy siblings from multiply affected families performed worse than those from the singleton families. CONCLUSIONS: The finding that the multiplex vs. singleton differences were selective to the backward visual span task, strengthens the view that the visual domain of working memory may provide a valuable endophenotypic marker for genetic schizophrenia studies.

Adult↗
PubMed2003

Evidence of susceptibility loci on 4q32 and 16p12 for bipolar disorder.

We performed a genome-wide scan for susceptibility loci in bipolar disorder in a study sample colleted from the isolated Finnish population, consisting of 41 families with at least two affected siblings. We identified one distinct locus on 16p12 providing significant evidence for linkage in two-point analysis (Z(max)=3.4). Furthermore, three loci with a two-point LOD score >2.0 were observed with markers on 4q32, 12q23 and Xq25, the latter locus having been earlier identified in one extended Finnish pedigree. In the second stage we fine mapped these chromosomal regions and also genotyped additional family members. In the fine mapping stage, 4q32 provided significant evidence of linkage for the three-point analyses (Z(max)=3.6) and 16p12 produced a three-point LOD score of 2.7. Since the identified chromosomal regions replicate earlier linkage findings in either bipolar disorder or other mental disorders, they should be considered good targets for further genetic analyses.

Alleles↗
PubMed2003

Seasonal changes, sleep length and circadian preference among twins with bipolar disorder.

BACKGROUND: We aimed at studying the seasonal changes in mood and behaviour, the distribution of hospital admissions by season, and the persistence of the circadian type in twins with bipolar disorder and their healthy co-twins. METHODS: All Finnish like-sex twins born from 1940 to 1969 were screened for a diagnosis of bipolar type I disorder. The diagnosis was assessed with a structured research interview, and the study subjects (n = 67) filled in the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Morningness-Eveningness Questionnaire (MEQ). For studying the persistence of the habitual sleep length and circadian type, we used data derived from the Finnish Twin Cohort Questionnaire (FTCQ). Bipolar twins were compared with their healthy co-twins. RESULTS: Bipolar twins had greater seasonal changes in sleep length (p = 0.01) and mood (p = 0.01), and higher global seasonality scores (p = 0.03) as compared with their co-twins with no mental disorder. Sunny days (p = 0.03) had a greater positive effect on wellbeing in the bipolar than healthy co-twins. CONCLUSIONS: Our results support the view that bipolar disorder is sensitive to the environmental influence in general and to the seasonal effect in specific. Exposure to natural light appears to have a substantial effect on wellbeing in twins with bipolar disorder.

Adult↗
PubMed2003

Association of dietary amino acids with low mood.

Diet may affect mood and cognitive functions. Tryptophan and serine augmentation strategies have been applied for patients with mood or psychotic disorders. We studied the association between dietary intake of amino acids and low mood. We studied 29,133 men aged 50-69 years for 5-8 years in a population-based trial in Finland. Intake of amino acids was calculated from a diet history questionnaire completed by 27,111 men at baseline. Self-reports of depressed mood were recorded thrice a year, data on hospital treatment due to depressive disorders were derived from the national Hospital Discharge Register, and suicides were identified from death certificates. Participants were smokers at study entry. Strengths of our study include detailed data on food consumption, a substantial number of study participants, a long prospective follow-up time, and versatile data on indices of low mood. We found no association between the dietary intake of amino acids and self-report of depressed mood or risk of suicide. However, dietary intake of lysine and serine was associated with risk of hospital treatment due to major depressive disorder but these associations disappeared after excluding from analysis those who had reported depressed mood at study entry. There is no consistent association between dietary intake of amino acids and low mood.

Aged↗
PubMed2003

Effect of controlled-release melatonin on sleep quality, mood, and quality of life in subjects with seasonal or weather-associated changes in mood and behaviour.

This study aimed to explore the effects of melatonin on sleep, waking up and well being in subjects with varying degrees of seasonal or weather-associated changes in mood and behaviour. Fifty-eight healthy adults exhibiting subsyndromal seasonal affective disorder (s-SAD) and/or the negative or positive type of weather-associated syndrome (WAS) were randomised to either 2 mg of sustained-release melatonin or placebo tablets 1-2 h before a desired bedtime for 3 weeks. Outcome measures were changes from baseline in sleep quality, sleepiness after waking, atypical depressive symptoms and health-related quality of life by week three. Early morning salivary melatonin concentrations were measured at baseline and treatment cessation in all subjects. Melatonin administration significantly improved the quality of sleep (P=0.03) and vitality (P=0.02) in the subjects with s-SAD, but attenuated the improvement of atypical symptoms and physical parameters of quality of life compared to placebo in the subjects with WAS, positive type.

Adult↗
PubMed2003

Timed bright-light exposure and complaints related to shift work among women.

OBJECTIVES: This field study measured whether repeated, brief exposures to bright light during night shifts improved subjective well-being during and after night work. A secondary objective was to investigate whether this response differed by season (summer or winter), seasonality, or age. METHODS: Eighty-seven healthy female nurses were voluntarily exposed to brief periods (4 x 20 minutes) of bright (5000 lux) light at scheduled times during every night shift over a 2-week period. Each morning following a night shift the subjects filled out self-assessment questionnaires measuring subjective symptoms and distress caused by work at night. The questionnaires were also completed 2 weeks before and after the light intervention. The study had two phases, summer (May-June) and winter (November-December). Thirty-seven of the subjects participated during both periods. RESULTS: Light significantly alleviated the subjective distress associated with nightshift work, both in summer and in winter, independent of the subject's age. The effect was stronger for those who reported routine seasonal changes in mood. CONCLUSIONS: Short pulses of timed bright-light exposure may enhance subjective adaptation to night work.

Adaptation, Psychological↗