Individuals experiencing a major depressive episode have a depressed mood and/or a diminished interest or pleasure in activities. Children experiencing a major depressive episode may appear or feel irritable rather than depressed.

Manic depression, or bipolar disorder, is a type of mood disorder that goes beyond the day's ordinary ups and downs. It is characterized by periodic episodes of extreme elation, elevated mood, or irritability countered by periodic classic depressive symptoms

Seasonal affective disorder (SAD) is a form of depression that affects people during the winter months. It generally begins as the days shorten in September and begins to go away as spring begins in April

It's not just biology that may account for the higher rate of depression in women. Social and cultural stressors may play a role, too. Although these stressors also occur in men, it's usually at a lower rate