Depression and anxiety are negative emotional states familiar to us all through personal experience. Less familiar are severe states of depression, in particular, which can actually shorten the lives of sufferers by over a decade. The relationship of these very severe states of illness to the milder cases more common earlier in development is important. Most patients who have suffered from depression will suffer from further episodes during their lifetime, and an early onset may make recurrence more likely. A number of factors increase the risk for depression, including family history, stressful life events, early life experiences, personality (particularly the traits of neuroticism and perfectionism) and mood lability (marked ups and downs). Sleep disturbance may both provoke and/or signal the onset of mood disorder. Sleep is therefore doubly important as a gateway to treatment. Understanding more about how sleep interacts with the established risk factors would allow vulnerable young people to be identified earlier for more effective intervention. Early identification of sleep disorder and depression allows psychological treatments to be used, which are less effective once a full depressive episode and a cascade of neurobiological and psychological effects have occurred.
anxiety, major depression, sleep