DEPRESSION

  What is depression ?

Depression is a common illness worldwide, with an estimated 3.8% of the population affected, including 5.0% among adults and 5.7% among adults older than 60 years (1). Approximately 280 million people in the world have depression (1). Depression is different from usual mood fluctuations and short-lived emotional responses to challenges in everyday life. Especially when recurrent and with moderate or severe intensity, depression may become a serious health condition. It can cause the affected person to suffer greatly and function poorly at work, at school and in the family. At its worst, depression can lead to suicide. Over 700 000 people die due to suicide every year. Suicide is the fourth leading cause of death in 15-29-year-olds.

Although there are known, effective treatments for mental disorders, more than 75% of people in low- and middle-income countries receive no treatment (2).  Barriers to effective care include a lack of resources, lack of trained health-care providers and social stigma associated with mental disorders. In countries of all income levels, people who experience depression are often not correctly diagnosed, and others who do not have the disorder are too often misdiagnosed and prescribed antidepressants.

Symptoms and patterns

During a depressive episode, the person experiences depressed mood (feeling sad, irritable, empty) or a loss of pleasure or interest in activities, for most of the day, nearly every day, for at least two weeks. Several other symptoms are also present, which may include poor concentration, feelings of excessive guilt or low self-worth, hopelessness about the future, thoughts about dying or suicide, disrupted sleep, changes in appetite or weight, and feeling especially tired or low in energy. 

In some cultural contexts, some people may express their mood changes more readily in the form of bodily symptoms (e.g. pain, fatigue, weakness).  Yet, these physical symptoms are not due to another medical condition. 

During a depressive episode, the person experiences significant difficulty in personal, family, social, educational, occupational, and/or other important areas of functioning. 

A depressive episode can be categorised as mild, moderate, or severe depending on the number and severity of symptoms, as well as the impact on the individual’s functioning. 

There are different patterns of mood disorders including:

• single episode depressive disorder, meaning the person’s first and only episode);
• recurrent depressive disorder, meaning the person has a history of at least two depressive episodes; and
• bipolar disorder, meaning that depressive episodes alternate with periods of manic symptoms, which include euphoria or irritability, increased activity or energy, and other symptoms such as increased talkativeness, racing thoughts, increased self-esteem, decreased need for sleep, distractibility, and impulsive reckless behaviour.

Depression causes

There are several possible causes of depression. They can range from biological to circumstantial.

Common causes include:

• Brain chemistry. There may be a chemical imbalance in parts of the brain that manage mood, thoughts, sleep, appetite, and behavior in people who have depression.
• Hormone levels. Changes in female hormones estrogen and progesterone during different periods of time like during the menstrual cycle, postpartum period, perimenopause, or menopause may all raise a person’s risk for depression.
• Family history. You’re at a higher risk for developing depression if you have a family history of depression or another mood disorder.
• Early childhood trauma. Some events affect the way your body reacts to fear and stressful situations.
• Brain structure. There’s a greater risk for depression if the frontal lobe of your brain is less active. However, scientists don’t know if this happens before or after the onset of depressive symptoms.
• Medical conditions. Certain conditions mayTrusted Source put you at higher risk, such as chronic illness, insomnia, chronic pain, Parkinson’s disease, stroke, heart attack, and cancer .
• Substance use. A history of substance or alcohol misuse can affect your risk.
• Pain. People who feel emotional or chronic physical pain for long periods of time are significantly more likelyTrusted Source to develop depression.

Risk factors

Risk factors for depression can be biochemical, medical, social, genetic, or circumstantial. Common risk factors include:

• Sex. The prevalence of major depression is twice as high in femalesTrusted Source as in males.
• Genetics. You have an increased riskTrusted Source of depression if you have a family history of it.
• Socioeconomic status. Socioeconomic status, including financial problems and perceived low social status, can increaseTrusted Source your risk of depression.
• Certain medications. Certain drugs including some types of hormonal birth control, corticosteroids, and beta-blockers may be associatedTrusted Source with an increased risk of depression.
• Vitamin D deficiency. StudiesTrusted Source have linked depressive symptoms to low levels of vitamin D.
• Gender identity. The risk of depression for transgender people is nearly 4-fold that of cisgender people, according to a 2018 study.
• Substance misuse. About 21 percent of people who have a substance use disorder also experience depression.
• Medical illnesses. Depression is associated with other chronic medical illnesses. People with heart disease are about twice as likelyTrusted Source to have depression as people who don’t, while up to 1 in 4 peopleTrusted Source with cancer may also experience depression.