Depression: Causes, Risk Factors & Symptoms

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

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

Symptoms

Depression can differ from person to person. Some people have only a few symptoms, while others have many.

Symptoms can change over time and may include:

• Persistent feelings of sadness, anxiety, or emptiness
• Hopelessness
• Feeling guilty, worthless, or helpless
• Loss of interest in hobbies and activities
• Loss of interest in sex
• Feeling tired
• Trouble concentrating, remembering, or making decisions
• Trouble sleeping, waking up too early, or oversleeping
• Eating more or less than usual
• Weight gain or weight loss
• Thoughts of death or suicide with or without suicide attempts
• Restlessness or irritability
• Physical symptoms that defy standard diagnosis and do not respond well to medical treatments