Depression – a common, serious mood disorder – can undermine quality of life and contribute to disability, especially in more severe or persistent cases.

In a given year, it’s estimated that 1 in 15 adults will experience depression or have at least one major depressive episode. The mood disorder can affect myriad aspects of a person’s life, from one’s ability to tackle daily activities and work to relationships.

Symptoms

While depression is often first diagnosed in adolescents and adults, it can occur at any age. Rather than involving fleeting sadness, hallmarks of the disorder like depressed or low mood and loss of interest or pleasure must continue for at least two weeks for a diagnosis of depression to be made.

Symptoms for major depressive disorder can be mild to severe and may include:

Feeling sad, hopeless or despondent.

A loss of pleasure or interest in things you once enjoyed.

Sleep disturbances – such as insomnia or sleeping too much.

A loss of energy or fatigue.

Recurrent thoughts of death or suicide.

Feelings of guilt or worthlessness.

Significant weight loss when not dieting or weight gain, or a noticeable decrease or increase in appetite.

Difficulty concentrating.

Agitation or restlessness.

Depression is often accompanied by anxiety as well, requiring individuals to manage both at the same time.

Causes

Studies indicate that a number of different genetic, biological, environmental and psychological factors can raise a person’s risk for developing depression.

As outlined by the National Institute of Mental Health, these can include having a personal or family history of depression, experiencing major life changes, trauma, stress and certain physical ailments and medications. These include drugs prescribed for everything from controlling high blood pressure to treating asthma to helping with smoking cessation. Serious and chronic medical illnesses, such as heart disease and diabetes, are also associated with higher rates of depression. So-called early life adversity like childhood trauma – including physical or sexual abuse – has also been linked to higher rates of depression not only around the time of the trauma but later in life as well.

Types

In addition to major depression, or major depressive disorder, and the variation in how long symptoms last and their severity, there are a number of other types of depression. NIMH lists several examples:

Persistent depressive disorder. Also called dysthymia, this involves depression symptoms that last for at least two years. This form of depression is not as severe as major depression, but the ongoing nature of this disorder can significantly interfere with a person’s life and relationships with the persistence of symptoms like a loss of interest in daily activities, diminished productivity and feelings of hopelessness. A person can also have episodes of major depression, alternating with periods of less severe symptoms.

Also called dysthymia, this involves depression symptoms that last for at least two years. This form of depression is not as severe as major depression, but the ongoing nature of this disorder can significantly interfere with a person’s life and relationships with the persistence of symptoms like a loss of interest in daily activities, diminished productivity and feelings of hopelessness. A person can also have episodes of major depression, alternating with periods of less severe symptoms. Perinatal or postpartum depression. Perinatal depression refers to major depression that some women experience during pregnancy or after delivery – which, in the latter case, is typically referred to as postpartum depression. Symptoms including extreme sadness, crying, anxiety, appetite disturbance and exhaustion can make it difficult to handle the challenges of pregnancy or caring for a new child.

Perinatal depression refers to major depression that some women experience during pregnancy or after delivery – which, in the latter case, is typically referred to as postpartum depression. Symptoms including extreme sadness, crying, anxiety, appetite disturbance and exhaustion can make it difficult to handle the challenges of pregnancy or caring for a new child. Psychotic depression. This is major depression accompanied by psychosis, or psychotic symptoms, including delusions, or false beliefs, and hallucinations – seeing or hearing things that aren’t there. These delusions and hallucinations are frequently related to the person’s depressed feelings, like hearing critical voices telling the individual that he or she doesn’t deserve to live.

This is major depression accompanied by psychosis, or psychotic symptoms, including delusions, or false beliefs, and hallucinations – seeing or hearing things that aren’t there. These delusions and hallucinations are frequently related to the person’s depressed feelings, like hearing critical voices telling the individual that he or she doesn’t deserve to live. Seasonal affective disorder . Also referred to as seasonal or winter depression, it tends to coincide with the changing seasons. Symptoms, from feeling depressed to having low energy, typically begin and end around the same time each year, frequently lasting from the late fall or early winter and going away in the spring and summer. (Less commonly episodes can occur during the summer.) Treatment approaches include light therapy – or exposure to artificial light – as well as therapy and medication traditionally prescribed for depression.

Also referred to as seasonal or winter depression, it tends to coincide with the changing seasons. Symptoms, from feeling depressed to having low energy, typically begin and end around the same time each year, frequently lasting from the late fall or early winter and going away in the spring and summer. (Less commonly episodes can occur during the summer.) Treatment approaches include light therapy – or exposure to artificial light – as well as therapy and medication traditionally prescribed for depression. Depression occurring with bipolar disorder. Bipolar disorder differs from depression since it involves alternating periods of unusually intense emotion. But along with manic episodes marked by extreme elation, sufferers also experience depressive episodes. Sometimes the same mood episode features both manic and depressive symptoms. Individuals with bipolar disorder also experience accompanying changes in sleep patterns and activity levels.

Diagnosis and Treatment

Experts advise people who suspect they or a loved one are suffering from depression to seek professional help so they can be properly diagnosed and treated. In particular, anyone who is having suicidal thoughts, experiencing psychosis or whose safety might otherwise be compromised is urged to get help immediately.

Treatments vary based on factors ranging from the depression type, symptoms and severity, and individual preference.

Most commonly major depression is treated with psychotherapy, or talk therapy – like cognitive behavioral therapy – or medication, and often the combination is recommended. Whether a person is selecting a therapist or therapeutic approach or trying different medications, it can take time to find the right fit. Even then, as with medications, results aren’t instantaneous. For example, it generally takes at least a couple weeks before antidepressants begin to work.

Besides medication and therapy, other approaches are also sometimes recommended depending on depression severity and type, from light therapy for seasonal affective disorder to exercise, which research has shown to be effective in preventing and treating depression, particularly for those experiencing milder depression symptoms. Alternative treatments from yoga to vitamin D supplements to meditation have also shown some promise but require more research.

Health Care Providers That Treat Depression