The incidence of<unk>  has been found to increase when the temperature and/or sunlight are low. According to the DSM-IV, the<unk>  features" specifier may be applied to the following only: #Major depressive episode, single episode #Major depressive episode, recurrent episode #Bipolar I disorder, most recent episode depressed #Bipolar II disorder, most recent episode depressed
Melancholic depression
Collective depression
Masked depression
Double depression
Depression 
Psychotic depression
Retarded depression
Late life depression