Depression Causes & Risks

Causes

The precise cause is not known. It can be difficult to determine if an illness causes depression or depression caused the illness. Possible causes may be mental, physical, or environmental and include:

Stressful life events (usually in combination with one or more of the following causes)
Chronic stress
Low self-esteem
Imbalances in brain chemicals and hormones
Lack of control over circumstances (helplessness and hopelessness)
Negative thought patterns and beliefs
Chronic pain
Heart disease and heart surgery
Genetic predisposition
Altered brain structure and function, including after a stroke
Parkinson’s disease
Postpartum depression occurs after childbirth
Seasonal affective disorder is a type of depression or a worsening of symptoms thought to be due to the decreased exposure to sunlight that occurs during winter months
Hypothyroidism
Anemia
Cancer
Substance abuse

Synapses in the Brain

Researchers are studying how problems with synapses in the brain may be linked to depression.

Risk Factors

Risk factors include:

Sex: female
Age: elderly
Chronic physical or mental illness, including thyroid disease, headaches, chronic pain, and stroke
Previous episode of depression
Major life changes or stressful life events (eg, bereavement, trauma )
Postpartum depression
Winter season for seasonal affective disorder
Little or no social support
Low self-esteem
Lack of personal control over circumstances
Family history of depression (parent or sibling)
Feelings of helplessness
Certain medications, including medications used to treat asthma , high blood pressure , arthritis, high cholesterol , and heart problems
Smoking
Anxiety
Insomnia
Personality disorders
Hypothyroidism
Type 2 diabetes

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