Ref: Synopsis of Psychiatry. Kaplan & Sadock, 10th edition. Diagnostic and Statistical Manual, IVth edition.Expanation:Electro-convulsive treatment (ECT)It is one of the physical methods used to treat major depression.Other methods to treat major depression are Vagal Nerve Stimulation (VNS), Deep Brain Stimulation (DBS), repetitive Transcranial Magnetic Stimulation (rTMS)The onset of action, hence the resolution of symptoms is rapid when compared to other modalities like anti-depressants and psychotherapy.ECT is also used to treat catatonia (of any cause), intractable OCD and unmanageable mania.ECT is useful in severe depression with high suicidal riski neglect of food intake/psychotic symptoms.Resistant depression (where symptoms persist in spite of at least two adequate drug trials), not chronic depression (which might be untreated or associated with organic conditions/social stressors) is the indication for ECTEndogenous depression is the one which occurs without any reasonable external stress and have strong genetic component.Reactive depression, as the name i ndicates occurs after a stress and usually subsides once the stressor is removed. It responds well to psychotherapy not to ECT.Typical symptoms of depressionPersistent (all the time) andPervasive {across any situation) sad mood.Decreased appetite (with weight loss) andInsomnia.Atypical depression is characterized bySad but reactive mood (with positive stimuli one feels better)Increased appetite (weight gain),Hypersomnia andIncreased interpersonal rejection sensitivity (hypersensitive to remarks/criticisms).It is usual 1 y seen in adolescent females, often associated with thyroid dysfunction.SSRIs, MAOIs (Mono Amine Oxidase Inhibitors) work better hut not TCAs (Tri Cyclic Antidepressants).