Depression is a serious mental health condition that can affect people of all ages and backgrounds. It is estimated that one in five adults in the United States will experience depression at some point in their lives. There are many different types of depression, each with its own unique set of symptoms and causes. In this article, we will explore the nine most common forms of depression, including major depressive disorder, persistent depressive disorder, bipolar disorder, seasonal affective disorder (SAD), psychotic depression, peripartum (postpartum) depression, premenstrual dysphoric disorder (PMDD) depression, situational depression, and dysthymia.

Major Depressive Disorder

Major depressive disorder (MDD) is the most common type of depression. People with MDD experience symptoms most of the day, every day. These symptoms can last for weeks or even months. Some people may have a single episode of major depression, while others experience it throughout their lives.

Regardless of how long symptoms last, major depression can cause problems with your relationships and daily activities.

Persistent Depressive Disorder

Persistent depressive disorder (PDD) is depression that lasts two years or more. People may also refer to this as dysthymia or chronic depression. Persistent depression may not feel as intense as major depression, but it can still strain relationships and make daily tasks difficult.

Persistent depression lasts for years in a row, so people with this type of depression may begin to feel that their symptoms are only part of their normal view of life.

Bipolar Disorder

Bipolar disorder is a mood disorder characterized by periods of abnormally elevated mood known as mania. These periods can be mild (hypomania) or they can be so extreme that they cause a marked deterioration in a person's life, require hospitalization, or affect a person's sense of reality. The vast majority of people with bipolar disorder also have episodes of major depression.

Seasonal Affective Disorder (SAD)

Seasonal affective disorder (SAD) usually begins in late fall and early winter and dissipates during spring and summer. Summer-related depressive episodes can occur, but are much less common than winter episodes of SAD. People diagnosed with SAD often experience feelings of sadness, fatigue, difficulty concentrating, and changes in appetite or sleep patterns.

Psychotic Depression

Some people with major depression may experience periods of psychosis.

This may involve hallucinations and delusions. Medical professionals refer to this as major depressive disorder with psychotic characteristics. However, some providers still refer to this phenomenon as depressive psychosis or psychotic depression.

Peripartum (Postpartum) Depression

Postpartum depression is characterized by feelings of sadness, indifference, exhaustion and anxiety that a woman may experience after the birth of her baby.

It affects one in nine women who have had a child and can affect any woman, regardless of age, race or economic status.

Premenstrual Dysphoric Disorder (PMDD)

Similar to perinatal depression, PMDD may be related to hormonal changes. Your symptoms often start right after ovulation and begin to subside once you have your period. PMDD is a severe form of premenstrual syndrome (PMS) that can cause depression, sadness, anxiety or irritability, as well as other extreme symptoms in the week before a woman's menstruation.

Situational Depression

Situational depression, or adjustment disorder with depressed mood, resembles major depression in many ways. It is caused by a stressful event such as the death of a loved one or the loss of a job. Symptoms include feelings of sadness or hopelessness; difficulty sleeping; changes in appetite; difficulty concentrating; fatigue; guilt; and thoughts of death or suicide.

Dysthymia

Dysthymia, also known as persistent depressive disorder (PDD), is a long-term form of depression that lasts for years and can interfere with daily life, work, and relationships.

Unlike major depression, a common sign of atypical depression is a feeling of heaviness in the arms and legs, as a form of paralysis. People diagnosed with dysthymia may also respond better to a type of antidepressant known as a monoamine oxidase inhibitor (MAOI). If you or someone you love is struggling with any type of depression, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.