It is characterized by sadness of mood, anhedonia, feeling of worthlessness and hopelessness, lack of energy and concentration, appetite disturbances, psychomotor agitation or retardation, sleep disturbances and suicidal thoughts.


  • Aetiology: Biological factors in the form of neurotransmitter disturbances especially serotonin, hormonal disturbances, neuroanatomical disturbances.
  • Various medical disorders predispose to depression as well most commonly- hypothyroidism, diabetes, and various vitamin and mineral deficiencies.
  • Neuroanatomical: Decreased activity in dorsolateral prefrontal cortex and increased activity in amygdala.
  • Genetic: there is found to a role of cAMP response element protein on chromosome 2, and serotonin transporter gene.
  • Psychological theories: according to these negative thoughts have a central role in development of depression. It is the second most prevalent mental health disorder according to WHO with a lifetime prevalence of 12%. It affects females twice compared to males. Depression is the most common cause of suicide.


For diagnosis minimum of 5 symptoms should persists for at least 2 weeks.


  • Pharmacotherapy in the form of Tricyclic antidepressants, Selective serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors.
  • Psychotherapy: Cognitive behaviourtherapy , interpersonal therapy.
  • ECT in cases of suicide risk
  • Transcranial magnetic stimulation
  • Vagal stimulation
  • Deep brain stimulation