The relationship between wearable-derived sleep features and relapse in Major Depressive Disorder.

BACKGROUND: Changes in sleep and circadian function are leading candidate markers for the detection of relapse in Major Depressive Disorder (MDD). Consumer-grade wearable devices may enable remote and real-time examination of dynamic changes in sleep. Fitbit data from individuals with recurrent MDD were used to describe the longitudinal effects of sleep duration, quality, and regularity on subsequent depression relapse and severity. METHODS: Data were collected as part of a longitudinal observational mobile Health (mHealth) cohort study in people with recurrent MDD. Participants wore a Fitbit device and completed regular outcome assessments via email for a median follow-up of 541 days. We used multivariable regression models to test the effects of sleep features on depression outcomes. We considered respondents with at least one assessment of relapse (n = 218) or at least one assessment of depression severity (n = 393). RESULTS: Increased intra-individual variability in total sleep time, greater sleep fragmentation, lower sleep efficiency, and more variable sleep midpoints were associated with worse depression outcomes. Adjusted Population Attributable Fractions suggested that an intervention to increase sleep consistency in adults with MDD could reduce the population risk for depression relapse by up to 22 %. LIMITATIONS: Limitations include a potentially underpowered primary outcome due to the smaller number of relapses identified than expected. CONCLUSION: Our study demonstrates a role for consumer-grade activity trackers in estimating relapse risk and depression severity in people with recurrent MDD. Variability in sleep duration and midpoint may be useful targets for stratified interventions.

Schizophrenia: epidemiology of mental disorders and psychosocial problems

Schizophrenia is a severe psychiattric disorder, which usually starts in adolescence or early adult life, and often becomes chronic and disabling. It is a major public health problem in many parts of the world, representing a heavy burden both for the families of affected individuals and for national health systems

This publication provides a broad overview of current knowledge about the epidemiology of schizophrenia, starting with an examination of relevant diagnostic and methodological issues. Incidence and prevalence studies in different settings are reviewed, and the various risk factors for the disorder are considered. Finally, a number of recommendations are made for future research. Annexed to the book are the ICD-10 clinical descriptions and diagnostic guidelines and the ICD-10 diagnostic criteria for research for this group of disorders