About one in five people will experience a depression during their lifetime.  Depressive disorders typically occur between the ages of 25 to 45 years. People suffering from depression tend to be seriously impaired in their daily functioning. Particularly vitality, social and role functioning, and mental well-being are most severely affected, with quality of life declining proportionately to the severity of their symptoms. People coping with depression often adopt an unhealthy lifestyle (e.g. increased use of tobacco and alcohol, poor diet). Of all people with a lifetime history of major depression, about 40% first developed the disorder between the ages of 15 and 35 years. In adults, depression is about one and a half times more prevalent in women than it is in men, while the course and relapse rates are similar. Today, there are effective treatments available, although, unfortunately, not all depressions respond equally well: an estimated 10-20% of people develop chronic depression.

Depressies worden multidisciplinair behandeld met behulp van een zogenaamde 'stepped care' behandelrichtlijn. Voor lichte depressies worden lichtere behandelingen geadviseerd en bij ernstige depressies ' zwaardere' behandelingen, die in de praktijk bestaan uit een combinatie van psycho-educatie, zelfmanagement, psychotherapie en/of antidespressieve medicatie.