Monthly fluctuations of insomnia symptoms in a population-based sample

Study Objectives: To document the monthly changes in sleep/insomnia status over a 12-month period; to determine the optimal time intervals to reliably capture new incident cases and recurrent episodes of insomnia and the likelihood of its persistence over time. Design: Participants were 100 adults (mean age = 49.9 years; 66% women) randomly selected from a larger population-based sample enrolled in a longitudinal study of the natural history of insomnia. They completed 12 monthly telephone interviews assessing insomnia, use of sleep aids, stressful life events, and physical and mental health problems in the previous month. A total of 1,125 interviews of a potential 1,200 were completed. Based on data collected at each assessment, participants were classified into one of three subgroups: good sleepers, insomnia symptoms, and insomnia syndrome. Results: At baseline, 42 participants were classified as good sleepers, 34 met criteria for insomnia symptoms, and 24 for an insomnia syndrome. There were significant fluctuations of insomnia over time, with 66% of the participants changing sleep status at least once over the 12 monthly assessments (51.5% for good sleepers, 59.5% for insomnia syndrome, and 93.4% for insomnia symptoms). Changes of status were more frequent among individuals with insomnia symptoms at baseline (mean = 3.46, SD = 2.36) than among those initially classified as good sleepers (mean = 2.12, SD = 2.70). Among the subgroup with insomnia symptoms at baseline, 88.3% reported improved sleep (i.e., became good sleepers) at least once over the 12 monthly assessments compared to 27.7% whose sleep worsened (i.e., met criteria for an insomnia syndrome) during the same period. Among individuals classified as good sleepers at baseline, risks of developing insomnia symptoms and syndrome over the subsequent months were, respectively, 48.6% and 14.5%. Monthly assessment over an interval of 6 months was found most reliable to estimate incidence rates, while an interval of 3 months proved the most reliable for defining chronic insomnia. Conclusions: Monthly assessment of insomnia and sleep patterns revealed significant variability over the course of a 12-month period. These findings highlight the importance for future epidemiological studies of conducting repeated assessment at shorter than the typical yearly interval in order to reliably capture the natural course of insomnia over time

On the Concept and Dimension of Human Capital in a Knowledge-Based

Economy Context Technological changes, along with the globalization of markets, are transforming industrial countries into knowledge-driven economies. This shift has made human capital one of the leading public policy themes. However, existing measures of investment do not allow policymakers to comprehend fully the implications of human capital on economic performance and technological advancement. This paper discusses the elements of a comprehensive definition of human capital and identifies the fundamental differences between human and physical capital. It shows that the main features of human capital and its differences with physical capital have implications for national income acounting, the classification of government expenditures, and the endogenous growth literature.

Génétique de la schizophrénie et de la maladie bipolaire

Des résultats indiquant des liaisons sur deux chromosomes pour la schizophrénie (SZ) et la maladie bipolaire (BP) furent trop hâtivement rapportés dans la revue Nature à la fin des années 1980. Les connaissances accumulées à partir des insuccès de la première génération d’études génétiques moléculaires de la SZ et de la BP ont toutefois permis de jeter les bases de la seconde génération d’études de liaison, qui donnent maintenant des résultats convergents fort encourageants. Cet article présente une douzaine de sites génomiques de susceptibilité pour la SZ et la BP, certains d’entre eux étant probablement partagés par ces deux psychoses majeures, tandis que d’autres seraient spécifiques à chacune

Génétique de la schizophrénie et de la maladie bipolaire

Des résultats indiquant des liaisons sur deux chromosomes pour la schizophrénie (SZ) et la maladie bipolaire (BP) furent trop hâtivement rapportés dans la revue Nature à la fin des années 1980. Les connaissances accumulées à partir des insuccès de la première génération d’études génétiques moléculaires de la SZ et de la BP ont toutefois permis de jeter les bases de la seconde génération d’études de liaison, qui donnent maintenant des résultats convergents fort encourageants. Cet article présente une douzaine de sites génomiques de susceptibilité pour la SZ et la BP, certains d’entre eux étant probablement partagés par ces deux psychoses majeures, tandis que d’autres seraient spécifiques à chacune.Results claming linkage on two chromosomes for schizophrenia (SZ) and bipolar affective disorder (BP) were prematurely published in Nature at the end of the ‘80s. This ended up into disappointment. The knowledge accumulated from the first generation of unsuccessful molecular genetics studies of SZ and BP provided a stronger basis for the following generation of linkage studies that are now yielding encouraging converging results. Hence, we report several genomics susceptibility loci for SZ and BP, some of them being probably shared by the two major psychiatric illnesses whereas others could be specific to each

Incidence, persistence, and remission rates of insomnia over 5 years

Importance: Insomnia is a significant public health problem, but there is little information on its natural history. Objective: To assess the incidence, persistence, and remission rates of insomnia over a 5-year naturalistic follow-up period. Design, settings and participants: This cohort study included participants with and without sleep problems selected from the adult population in Canada from August 2007 to June 2014. Participants completed an annual survey about their sleep and health status for 5 consecutive years. Exposure: Using validated algorithms, participants were classified at each assessment as being good sleepers (n = 1717), having an insomnia disorder (n = 538), or having subsyndromal insomnia (n = 818). Main outcomes and methods: Survival analyses were used to derive incidence rates of new insomnia among the subgroup of good sleepers at baseline and persistence and remission rates among those with insomnia at baseline. Sleep trajectories were examined by looking at year-person transitions between each consecutive year summed over the 5-year follow-up period. All inferential analyses were weighted according to normalized sampling weights. Results: The sample included 3073 adults (mean [SD] age, 48.1 [15.0] years; range, 18.0-95.0 years; 1910 [62.2%] female). Overall, 13.9% (95% CI, 11.0%-17.5%) of initial good sleepers developed an insomnia syndrome during the 5-year follow-up period, and incidence rates were higher among women than among men (17.6% [95% CI, 13.6%-22.7%] vs 10.1% [95% CI, 6.6%-15.3%; χ2 = 4.43; P = .03). A total of 37.5% (95% CI, 32.6%-42.5%) of participants with insomnia at baseline reported insomnia persisting at each of the 5 annual follow-up times. For subsyndromal insomnia, rates were 62.5% at 1 year to 26.5% at 5 years. For syndromal insomnia, rates were 86.0% at 1 year to 59.1% at 5 years. Conversely, remission rates among those with subsyndromal insomnia were almost double the rates among those with an insomnia syndrome at 1 year (37.5% [95% CI, 31.7%-44.0%] vs 14.0% [95% CI, 9.3%-20.8%]), 3 years (62.7% [95% CI, 56.7%-68.7%] vs 27.6% [95% CI, 20.9%-35.9%]), and 5 years (73.6% [95% CI, 68.0%-78.9%%] vs 40.9% [95% CI, 32.7%-50.4%]). Yearly trajectories showed that individuals who were good sleepers at baseline were 4.2 (95% CI, 3.51-4.89) times more likely to stay good sleepers in the subsequent year, but once they developed insomnia, they were equally likely to report symptoms (47% probability) than to return to a good sleeper status (53% probability) 1 year later. Similarly, those with an insomnia syndrome at any given assessment were more likely (adjusted odds ratio, 1.60; 95% CI, 1.19-2.60) to remain in that status (persistence) than to improve (remittance) at the next assessment; even among those who improved, the odds of relapse were greater (adjusted odds ratio, 2.04; 95% CI, 1.23-3.37) than those to improve in the following year. Conclusion and relevance: The findings suggest that insomnia is often a persistent condition. Considering the long-term adverse outcomes associated with persistent insomnia, these findings may have important implication for the prognosis and management of insomnia

Supplementary Material for: Detection of Phenotype Modifier Genes Using Two-Locus Linkage Analysis in Complex Disorders Such as Major Psychosis

<b><i>Objective:</i></b> To increase power to detect modifier loci conferring susceptibility to specific phenotypes such as disease diagnoses which are part of a broader disorder spectrum by jointly modeling a modifier and a broad susceptibility gene and to identify modifier loci conferring specific susceptibility to schizophrenia (SZ) or to bipolar disorder (BP) using the approach. <b><i>Methods:</i></b> We implemented a two-locus linkage analysis model where a gene 1 genotype increases the risk of a broad phenotype and a gene 2 genotype modifies the expression of gene 1 by conferring susceptibility to a specific phenotype. <b><i>Results:</i></b> Compared to a single-locus analysis within the broad phenotype, the proposed approach had greater power to detect the modifier gene 2 (0.96 vs. 0.54 under a simulation scenario including heterogeneity). In a sample of 12 mixed SZ and BP Eastern Quebec kindreds, D8S1110 at 8p22 showed the strongest evidence of linkage to a gene determining a specific phenotype (SZ or BP) among subjects susceptible to major psychosis because of putative genes at 10p13 (D10S245, conditional maximized LOD (cMOD) = 4.20, p = 0.0003) and 3q21–q23 (D3S2418, cMOD = 4.09, p = 0.0005). <b><i>Conclusion:</i></b> The proposed strategy is useful to detect modifier loci conferring susceptibility to a specific phenotype within a broader phenotype