[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"condition-major-depression":3},{"id":4,"title":5,"abbr":6,"assessments":7,"bgClass":36,"body":37,"category":6,"comorbidities":44,"description":75,"dsmCriteria":76,"etiology":104,"extension":147,"heroSubtitle":148,"heroTitle":149,"icdCode":150,"icon":85,"iconClass":151,"labelClass":6,"lastReviewed":6,"meta":152,"name":175,"navigation":176,"onsetAge":177,"path":178,"prevalence":179,"ratio":180,"responseRate":47,"seo":181,"slug":182,"sources":183,"stem":204,"takeaways":6,"tools":6,"treatments":205,"__hash__":240},"conditions\u002Fconditions\u002Fmajor-depression.md","MDD Clinical Guide: PHQ-9, DSM-5-TR and Treatment Tiers",null,[8,15,22,29],{"name":9,"fullName":10,"description":11,"scoring":12,"timeframe":13,"icon":14},"PHQ-9","Patient Health Questionnaire-9","Brief 9-item self-report measure directly corresponding to DSM-5-TR depression criteria; most widely used in primary care.","0-4 minimal, 5-9 mild, 10-14 moderate, 15-19 moderately severe, 20-27 severe depression","2-5 minutes","ph:clipboard-text",{"name":16,"fullName":17,"description":18,"scoring":19,"timeframe":20,"icon":21},"BDI-II","Beck Depression Inventory-II","21-item self-report assessing cognitive, affective, somatic, and vegetative symptoms over past 2 weeks.","0-13 minimal, 14-19 mild, 20-28 moderate, 29-63 severe depression","5-10 minutes","ph:heart",{"name":23,"fullName":24,"description":25,"scoring":26,"timeframe":27,"icon":28},"MADRS","Montgomery-Åsberg Depression Rating Scale","Clinician-rated 10-item scale sensitive to change; preferred for treatment trials and monitoring.","0-6 normal, 7-19 mild, 20-34 moderate, >34 severe; change ≥50% indicates response","15-20 minutes","ph:user-circle",{"name":30,"fullName":31,"description":32,"scoring":33,"timeframe":34,"icon":35},"QIDS-SR16","Quick Inventory of Depressive Symptomatology","16-item self-report covering all 9 DSM symptom domains; sensitive to change, useful for monitoring.","0-5 none, 6-10 mild, 11-15 moderate, 16-20 severe, 21-27 very severe","5-7 minutes","ph:chart-line","bg-indigo-500\u002F10",{"type":38,"value":39,"toc":40},"minimark",[],{"title":41,"searchDepth":42,"depth":42,"links":43},"",2,[],[45,50,55,60,65,70],{"condition":46,"prevalence":47,"note":48,"icon":49},"Anxiety Disorders","50-60%","GAD, panic disorder, social anxiety frequently co-occur; shared neurobiological pathways","ph:warning-circle",{"condition":51,"prevalence":52,"note":53,"icon":54},"Substance Use Disorders","20-30%","Alcohol and cannabis most common; self-medication hypothesis; worsens depression course","ph:pill",{"condition":56,"prevalence":57,"note":58,"icon":59},"PTSD","15-30%","Trauma history common; depression may be secondary to unprocessed trauma","ph:warning-octagon",{"condition":61,"prevalence":62,"note":63,"icon":64},"Chronic Pain","30-50%","Bidirectional relationship; shared serotonin\u002Fnorepinephrine pathways","ph:lightning",{"condition":66,"prevalence":67,"note":68,"icon":69},"Obsessive-Compulsive Disorder","10-25%","OCD symptoms may predate or emerge during depressive episodes","ph:arrows-clockwise",{"condition":71,"prevalence":72,"note":73,"icon":74},"Eating Disorders","5-10%","Particularly in females; bulimia nervosa and binge eating disorder most common","ph:fork-knife","Clinical guide to Major Depressive Disorder: PHQ-9, BDI-II, and MADRS protocols, DSM-5-TR diagnostic criteria, comorbidities, and evidence-based treatment.",[77,82,96],{"title":78,"subtitle":79,"icon":49,"items":80},"Core Symptom Requirement","5+ symptoms during the same 2-week period",[81],"At least one must be (1) depressed mood or (2) loss of interest\u002Fpleasure",{"title":83,"subtitle":84,"icon":85,"items":86},"Symptom Cluster","Clinical manifestations:","ph:cloud-rain",[87,88,89,90,91,92,93,94,95],"Depressed Mood (Subjective or observed)","Anhedonia (Markedly diminished interest or pleasure)","Weight\u002FAppetite Change (Significant loss or gain)","Sleep Disturbance (Insomnia or hypersomnia)","Psychomotor Agitation\u002FRetardation (Observable)","Fatigue\u002FLoss of Energy","Worthlessness\u002FGuilt (Excessive or inappropriate)","Concentration Difficulties (or indecisiveness)","Suicidal Ideation (Recurrent thoughts of death)",{"title":97,"subtitle":98,"icon":99,"items":100},"Additional Requirements","Diagnostic caveats:","ph:warning",[101,102,103],"Symptoms cause significant distress or impairment","Not attributable to substance use or medical condition","No history of manic or hypomanic episodes",[105,116,126,137],{"category":106,"factors":107,"icon":114,"color":115},"Neurobiological",[108,109,110,111,112,113],"Monoamine dysregulation (serotonin, norepinephrine, dopamine)","Reduced hippocampal volume and neurogenesis","Prefrontal cortex hypoactivity","Amygdala hyperactivity (negative emotional processing)","HPA axis dysfunction (cortisol dysregulation)","Neuroinflammation and cytokine elevation","ph:brain","primary",{"category":117,"factors":118,"icon":124,"color":125},"Genetic",[119,120,121,122,123],"Heritability: 30-40% (moderate genetic component)","Polygenic risk involving 100+ genes","5-HTTLPR polymorphism (serotonin transporter)","BDNF gene variants (neuroplasticity)","First-degree relatives have 2-3x increased risk","ph:dna","secondary",{"category":127,"factors":128,"icon":135,"color":136},"Environmental",[129,130,131,132,133,134],"Early childhood adversity and trauma","Chronic stress and major life events","Social isolation and lack of support","Socioeconomic disadvantage","Medical illness (stroke, cancer, chronic pain)","Substance use (alcohol, sedatives)","ph:globe","accent",{"category":138,"factors":139,"icon":145,"color":146},"Psychological",[140,141,142,143,144],"Negative cognitive schemas (Beck's cognitive triad)","Rumination and cognitive inflexibility","Learned helplessness and external locus of control","Perfectionism and self-criticism","Reduced reward sensitivity (anhedonia)","ph:lightbulb","info","md","A mood disorder characterized by persistent depressed mood or loss of interest\u002Fpleasure, accompanied by cognitive, behavioural, and somatic symptoms that significantly impair functioning.","Major \u003Cbr \u002F> \u003Cspan class='text-gradient-flow'>Depressive Disorder\u003C\u002Fspan>","F32.9","text-indigo-500",{"faqs":153},[154,157,160,163,166,169,172],{"question":155,"answer":156},"What is Major Depressive Disorder?","Major Depressive Disorder (MDD) is a mood disorder defined in DSM-5-TR (ICD-11 codes F32.x for single episode, F33.x for recurrent) by persistent depressed mood or loss of interest, plus at least four additional symptoms across cognitive, behavioural, and somatic domains, present nearly every day for at least 2 weeks. Symptoms must produce clinically significant distress or functional impairment. Episodes are classified by severity (mild, moderate, severe) and may include specifiers like with anxious distress, melancholic features, or peripartum onset.",{"question":158,"answer":159},"What are the symptoms of Major Depressive Disorder?","Diagnostic criteria require five or more of nine symptoms during the same 2-week period, with at least one being depressed mood or loss of interest. The full symptom list includes depressed mood, anhedonia (loss of interest or pleasure), significant weight or appetite change, insomnia or hypersomnia, psychomotor agitation or retardation, fatigue, feelings of worthlessness or guilt, difficulty concentrating, and recurrent thoughts of death or suicidal ideation. Symptoms must represent a change from baseline functioning.",{"question":161,"answer":162},"How is Major Depressive Disorder diagnosed?","Diagnosis is made by a clinician using DSM-5-TR criteria, supported by validated scales. The PHQ-9 (9 items, 2 to 3 minutes) is the most widely used screener; a score of 10 or above has 88% sensitivity and 88% specificity for major depression. The BDI-II is an established alternative. The MADRS (Montgomery-Åsberg Depression Rating Scale) is the criterion-standard clinician-rated severity measure. A full clinical evaluation rules out bipolar disorder (the most clinically important differential), substance-induced mood disorder, and depression secondary to medical conditions like hypothyroidism.",{"question":164,"answer":165},"What causes Major Depressive Disorder?","MDD has a moderate genetic component with heritability around 35 to 40 percent. Multiple genes contribute, including those involved in serotonin signaling (5-HTTLPR), BDNF, and stress response regulation. Neurobiologically, depression involves dysregulation of monoamine systems (serotonin, norepinephrine, dopamine), HPA axis hyperactivity, hippocampal volume reduction, and altered prefrontal-limbic connectivity. Environmental contributors include childhood adversity, recent stressful life events, chronic medical illness, social isolation, and substance use. Cognitive vulnerability factors include negative attributional style and rumination.",{"question":167,"answer":168},"How is Major Depressive Disorder treated?","First-line treatments are Cognitive Behavioural Therapy (CBT), Behavioural Activation, Interpersonal Psychotherapy (IPT), and SSRI or SNRI antidepressants. Response rates are 50 to 60 percent for psychotherapy and pharmacotherapy individually, and combined treatment outperforms either alone for moderate-to-severe presentations. For treatment-resistant depression, second-line options include augmentation with atypical antipsychotics, lithium, or thyroid hormone; switching to an alternative agent; ketamine or esketamine; and rTMS. ECT remains effective for severe, treatment-refractory, or psychotic depression.",{"question":170,"answer":171},"How long does Major Depressive Disorder last?","An untreated major depressive episode typically lasts 6 to 12 months, though some episodes resolve more quickly and others persist longer. Treatment shortens episodes substantially, with most patients showing meaningful response within 4 to 8 weeks of starting evidence-based therapy or medication. MDD is often recurrent: approximately 50 percent of patients who recover from a first episode will have a second, and risk increases with each subsequent episode. About 20 percent of patients develop persistent depressive disorder lasting 2 or more years.",{"question":173,"answer":174},"Can Major Depressive Disorder be cured?","MDD is treated and managed rather than cured in the strict sense, but full remission is a realistic and common outcome of evidence-based treatment. Approximately 50 to 60 percent of patients respond to first-line treatment, and a substantial subset achieve full remission with no residual symptoms. Continuing antidepressants for 6 to 12 months after remission reduces relapse risk by roughly half. CBT skills produce more durable effects than medication alone because patients learn techniques they can deploy if symptoms return. Recurrent depression is best managed as a chronic relapsing-remitting condition with maintenance treatment.","Major Depressive Disorder",true,"~32","\u002Fconditions\u002Fmajor-depression","17%","2:1",{"title":5,"description":75},"major-depression",[184,187,191,194,197,200],{"title":185,"citation":186,"icon":14},"PHQ-9 Validation","Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001;16(9):606-613.",{"title":188,"citation":189,"icon":190},"DSM-5-TR Criteria","American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). 2022.","ph:book-open",{"title":192,"citation":193,"icon":114},"CBT Efficacy Meta-Analysis","Cuijpers P, Berking M, et al. A meta-analysis of cognitive-behavioural therapy for adult depression. J Affect Disord. 2013;142(1-3):1-8.",{"title":195,"citation":196,"icon":54},"Antidepressant Efficacy (STAR*D)","Rush AJ, Trivedi MH, et al. Acute and longer-term outcomes in depressed outpatients requiring one or several treatment steps: STAR*D trial. Am J Psychiatry. 2006;163(11):1905-1917.",{"title":198,"citation":199,"icon":114},"Neurobiology of Depression","Duman RS, Aghajanian GK, et al. Synaptic dysfunction in depression: potential therapeutic targets. Science. 2012;338(6103):68-72.",{"title":201,"citation":202,"icon":203},"Behavioural Activation","Dimidjian S, Hollon SD, et al. Randomized trial of behavioural activation, cognitive therapy, and antidepressant medication. J Consult Clin Psychol. 2006;74(4):658-670.","ph:intersect","conditions\u002Fmajor-depression",[206,212,217,222,228,234],{"name":207,"type":208,"description":209,"efficacy":210,"notes":211,"icon":114},"Cognitive Behavioural Therapy (CBT)","First-line","Structured therapy targeting negative thought patterns, behavioural activation, and skill-building for depression.","50-60% response rate; effect size 0.7-0.8; comparable to antidepressants for mild-moderate","12-16 sessions; durable effects post-treatment; prevents relapse",{"name":213,"type":208,"description":214,"efficacy":215,"notes":216,"icon":54},"SSRIs\u002FSNRIs","Selective serotonin reuptake inhibitors (fluoxetine, sertraline, escitalopram) and serotonin-norepinephrine reuptake inhibitors (venlafaxine, duloxetine).","50-60% response rate; 4-8 weeks for full effect; NNT ~7 for response","Titrate slowly; monitor suicidality in first weeks; taper to discontinue",{"name":201,"type":208,"description":218,"efficacy":219,"notes":220,"icon":221},"Structured increase in rewarding activities and reduction of avoidance; addresses anhedonia and withdrawal.","Effect sizes comparable to CBT; particularly effective for severe depression","Simpler than CBT; can be delivered by non-specialists","ph:lightning-slash",{"name":223,"type":208,"description":224,"efficacy":225,"notes":226,"icon":227},"Interpersonal Therapy (IPT)","Time-limited therapy focusing on interpersonal disputes, role transitions, grief, or interpersonal deficits.","Equivalent to CBT for acute depression; particularly for interpersonal stressors","12-16 sessions; addresses life transitions and relationship conflicts","ph:users",{"name":229,"type":230,"description":231,"efficacy":232,"notes":233,"icon":64},"Electroconvulsive Therapy (ECT)","Adjunct","Electrical stimulation under anesthesia; most effective treatment for severe or treatment-resistant depression.","70-90% response rate in treatment-resistant cases; rapid onset (2-4 weeks)","Reserved for severe, psychotic, or refractory depression; cognitive side effects",{"name":235,"type":230,"description":236,"efficacy":237,"notes":238,"icon":239},"Transcranial Magnetic Stimulation (TMS)","Non-invasive brain stimulation targeting dorsolateral prefrontal cortex; for treatment-resistant depression.","30-50% response in treatment-resistant; 20-30 sessions over 4-6 weeks","Clinically validated; fewer side effects than ECT; no anesthesia required","ph:pulse","vm7WrTuPVzQcXsq8PN1376SzGGiGCFrvUNteRi_S90o"]