There are other kinds of depressive disorders, including:
Seasonal Affective Disorder (SAD)
People with SAD experience mood changes and symptoms similar to depression, but these coincide with changes in the seasons (normally over winter months, but some people can experience it in summer). Spending time outside in nature is a treatment for SAD. For those with winter-based depression, getting enough light and Vitamin D can help alleviate depressive symptoms.
People with perinatal depression experience depressed mood as a direct result of pregnancy or childbirth, or following the birth of a child. This type of depression is linked to hormonal changes.