The lack of supportive social relations is significantly related to the occurrence of depressive complaints. This has been demonstrated in population studies as well as in clinical studies. This relation may reflect a causative role of social support in the development of depression. However, there are alternative explanations. The lack of support may simply be an expression of the depressed condition, that is supportive relations may not be valued as such by the subject because of his/her depressive mood. The causative role of social support has not been convincingly demonstrated till now. Research in this area has been hampered by the fact that social support is not a unitary concept. Its different forms and aspects are discussed.