Causes of Depression

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Many factors ranging from loss of a loved one, disharmony in interpersonal relations to serious changes in levels of chemicals in the  brain are attributed as cause of depression but what exactly causes depression is still unknown. It is seen to be an interplay of the following factors:

Biological factors

  • It has been established that there is decreased secretion from brain of certain biogeneic amines e.g. serotonin, norepinephrine and dopamine in depression.
  • Decreased secretion of certain hormones e.g. thyroid stimulating hormone, cortisol and growth hormone is also associated with depression.

Genetic factors

Data strongly indicates that genetic factors do play a role in causing depression. Children of parents with mood disorders are at a higher risk.

Psychosocial factors

Life stressors are seen to be related to precipitating depression.

Life Events: The first episode of depression is often preceded by a stressful life event, this increases the risk of future episodes even in the absence of external stressors. The life events known to cause depression are:

  • Loss of a parent before the age of 11 years
  • Loss of a spouse
  • Loss of a job or in business
  • Financial loss/difficulties
  • Divorce or separation
  • Failure in love
  • Failure in exams
  • Family conflict
  • Any unexpected death in the family/friends

Physical illness: Physical illness by itself is a stress but there are certain categories of diseases which are known to cause clinical depression. These medical conditions include:

  • Stroke
  • Hyperthyroidism
  • Hepatitis
  • Parkinson’s disease
  • Alzheimer’s dementia
  • Vitamin B12 deficiency
  • HIV infection
  • Certain cancers (Pancreas)
  • Cushing’s disease
  • Diseases of kidney (End Stage).

Substance (Drug) Abuse and Alcoholism: Many illicit drugs cause depression either on intoxication or during the withdrawal state (i.e. when individual is off the drugs). These drugs are:

  • Alcohol
  • Amphetamine
  • Cocaine
  • Opioid
  • Tranquilizers like diazepam

There are certain categories of prescribed medications that are also known to cause depression. These are:

  • Certain Painkillers
  • Antihypertensives
  • Certain Oral Contraceptive Pills
  • Tranquilizers
  • Anti epilepsy drugs
  • Anti ulcer drugs
  • Steroids, anabolic steroids
  • Sex hormones

Heavy metals and toxins like gasoline, paint, organophosphates, nerve gases, carbon mono oxide can also cause depression.