Increases in sleep duration are associated with cognitive impairment. A biological explanation for this association is currently lacking. Increases in sleep duration could be a marker of cognitive deficits.

Objective To study the relation between measures of personality and risk of cardiovascular disease and cancer in a large cohort. Design Follow-up of population based cohort. Setting Heidelberg, Germany. Participants 5114 women and men aged 40-65 in 1992-5. Main outcome measures Psychological traits assessed by several standardised personality questionnaires in 1992-5, related to cause of death (to 2002-3) or reported incidence of cardiovascular diseases and cancer (validated by treating doctors). Relative risks (and 95% confidence intervals) for combined morbidity and mortality according to five important personality traits were estimated using multivariable Cox proportional hazards models. Results During median follow-up of 8.5 years, 257 participants died and 72 were diagnosed with a heart attack, 62 with stroke, and 240 with cancer (morbidity and mortality combined). A high internal locus of control over disease was associated with a decreased risk of myocardial infarction (adjusted relative risk for an increase of 1 SD = 0.75; 95% confidence interval 0.58 to 0.96). An increase of 1 SD in time urgency was associated with a decreased risk of cancer (adjusted relative risk 0.83; 0.73 to 0.95). Other major personality traits-anger control, psychoticism, and symptoms of depression-were not consistently associated with myocardial infarction, stroke, or cancer. Conclusion Internal locus of control over disease and time urgency seem to be associated with reduced risk for common chronic diseases, probably by affecting unmeasured health related behaviour. The other personality traits assessed had no major impact on cardiovascular disease and cancer.

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Genome-wide association studies have reported an association between the A-allele of rs1006737 within CACNA1C and affective disorders and schizophrenia. The aim of the present study was to investigate the relationship between rs1006737 and established and potential endophenotypes for these disorders in a population-based cohort of 3793 subjects, using an analytical method designed to assess a previously reported sex-specific effect of CACNA1C. The investigated endophenotypes included personality traits and resilience factors. At 10-year follow-up, subjects were screened for depressive symptoms. All subjects were genotyped for rs1006737. The direction of the effect and mode of inheritance of rs1006737 differed between the sexes. In men, the A-allele was associated with higher emotional lability and lower resilience, that is, lower sense of coherence (P=0.021), lower perceived social support (P=0.018), lower dispositional optimism (P=0.032) and more depressive symptoms at follow-up (P=0.007). In women, the A-allele was associated with lower emotional lability and stronger resilience, that is, higher sense of coherence (P=0.00028), higher perceived social support (P=0.010), lower neuroticism (P=0.022) and fewer depressive symptoms at follow-up (P=0.035). After conservative Bonferroni correction for 32 tests, results only remained significant for sense of coherence in women (P=0.009). These results suggest that CACNA1C is involved in the genetic architecture of endophenotypes for affective disorders and schizophrenia, and that it shows a distinct sex-specific effect. Comprehensive phenotype characterization in case-control samples and the general population, as well as an adequate modeling of sex-specific genetic effects, may be warranted to elucidate the pathogenetic mechanisms conferred by robustly identified susceptibility genes.

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