What causes Depression?

Updated: Jan 7

Depression is thought to multi-factorial in its causes. The "Stress-Diathesis mode" combines these multifactorial causes to explain how each interact to cause the symptom of depression.

GENETICS has been proven by twin studies (first degree relatives are twice as likely to be depressed). Offending genes research include the serotonin transporter gene issue (5HTT promoter short allele), 5HT 1A receptor gene

  • Current candidates for future gene biomarkers (including BPAD):

  • Seritonin transporter gene, COMT gene, BDNF (Brain-derived neurotropic factor) gene, Tyrosine hydroxylase gene (think MAOIs)

PERSONALITY ie. Neuroticism with sensitivity to negative stimuli (enduring pattern of perceiving and interacting with the world) as derived from

  • 1) genetics

  • 2) early life experiences ie divorces, severe childhood trauma (four times as likely to be depressed), parenting styles ie. detached, overly stric


  • Acute stressors, esp 1) Losses ie. relationship breakdown, bereavement 2) Humiliation ie. losing job 3) Drug use

  • Chronic stressors ie. long standing stressors such as decreased social support (no one to confide to), chronic illness]

  • Childhood stressors: Sexual trauma, Distruptive bonding (attachment theory) or Overprotective parenting, family environments with high levels of emotional expression

The stress diathesis model suggests that people who develop depression were predisposed by their genetic and personality. The symptoms of depression were then made visible following the life event (psychosocial stressors)

How to treat?

Medication, talking therapy and neurostimulation (TMS) are the 3 broad domains in treating clinical depression. An additional therapy for treatment resistant depression that will soon become more available includes ketamine/esketamine nasal sprays.