What is Major Depressive Disorder (MDD)?

13 min read Updated 2 June 2026 Medically reviewed

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Key takeaways

Major Depressive Disorder (MDD) is the most common clinical depression diagnosis, defined by DSM-5 as one or more episodes of 5 or more specific symptoms (out of 9 listed) lasting at least 2 weeks, with at least one being depressed mood or loss of interest, and causing significant functional impairment.
The 9 DSM-5 symptoms span emotional (depressed mood, anhedonia, worthlessness/guilt), cognitive (concentration problems, suicidal thoughts), and physical (sleep, appetite/weight, psychomotor changes, fatigue) domains. Five must be present nearly every day for 2 weeks or longer.
MDD has three severity grades (mild, moderate, severe) and multiple specifiers describing features (melancholic, atypical, anxious distress, peripartum, seasonal, with psychotic features). These guide treatment selection.
Episodes typically last 6-12 months untreated; 6-12 weeks with effective treatment. After one episode, 50 percent will have another; after two, 70 percent will have a third; after three, 90 percent will have another. This recurrence pattern shapes treatment duration recommendations.
MDD is highly treatable. 60-80 percent of patients respond well to first-line treatment combining psychotherapy (CBT, behavioural activation, IPT), medication (SSRIs, SNRIs), and lifestyle measures. Treatment-resistant depression (10-30 percent of patients) has additional specialist options.

Medically reviewed by Dr. Boppana Sridhar (MBBS, MD Psychiatry, Australia-trained), Consultant Psychiatrist with 9+ years of clinical experience diagnosing and treating Major Depressive Disorder across mild-to-severe presentations including melancholic and atypical subtypes, comorbid presentations, and treatment-resistant cases. NMC-registered.

Last updated: 2 June 2026 | Last medically reviewed: 2 June 2026

Major Depressive Disorder (MDD) is the most common clinical depression diagnosis and one of the most common mental health conditions globally, affecting an estimated 280 million people worldwide per WHO. MDD is distinct from temporary sadness and from other mood disorders including persistent depressive disorder and bipolar disorder. This guide provides a comprehensive overview of MDD: the formal DSM-5 diagnostic criteria with each of the 9 symptoms explained, severity grades, specifiers that describe additional features, course patterns and recurrence rates, how MDD is distinguished from related conditions, common comorbidities, prognosis with treatment, treatment-resistant patterns, India-specific context including NMHS data, and when to seek help. The aim is to provide reliable information that supports informed conversations with healthcare professionals.

Definition and clinical overview

Major Depressive Disorder is a clinical mental health condition characterised by one or more major depressive episodes. A major depressive episode is defined by a constellation of symptoms (mood, cognitive, physical, behavioural) lasting at least 2 weeks and causing significant distress or functional impairment.

The term "major" in MDD refers to severity threshold and discrete-episode pattern, not necessarily extreme severity. MDD includes mild, moderate, and severe presentations. What distinguishes MDD from other depressive conditions is the pattern of discrete episodes meeting full criteria, separated by periods of substantially better functioning (in single-episode MDD) or by partial or full recovery (in recurrent MDD).

MDD is coded in ICD-10 as F32 (single episode) or F33 (recurrent depressive disorder). DSM-5 uses Major Depressive Disorder for both, with specifiers indicating single vs recurrent. Globally, WHO estimates approximately 280 million people live with depression. Lifetime prevalence ranges from 5 percent (India per NMHS) to 20 percent (some Western populations), with differences reflecting both genuine epidemiological variation and methodological factors including stigma effects on reporting.

MDD is more than emotional distress; it involves measurable changes in brain function (neural circuit alterations, particularly in mood-regulating regions), neurochemistry (dysregulation of serotonin, norepinephrine, dopamine), stress response systems (HPA axis dysregulation), and sometimes inflammatory markers. Understanding MDD as a medical condition affecting brain function helps reduce the stigma that frames depression as character weakness or insufficient effort.

The 9 DSM-5 criteria

DSM-5 specifies that a major depressive episode requires 5 or more of 9 specific symptoms present nearly every day for at least 2 weeks, with at least one being depressed mood or loss of interest (anhedonia). The full criteria include functional impairment and exclusion of other causes.

1. Depressed mood

Depressed mood most of the day, nearly every day, indicated by either subjective report (feeling sad, empty, hopeless) or observation by others (appearing tearful, withdrawn). In children and adolescents, can present as irritable mood rather than sadness.

2. Anhedonia

Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day. Activities previously enjoyed produce no pleasure or interest. This is often the most distressing symptom for patients because it removes life's ordinary rewards.

3. Significant weight or appetite change

Significant weight loss when not dieting or weight gain (more than 5 percent of body weight in a month) or decrease or increase in appetite nearly every day. In children, can present as failure to make expected weight gains.

4. Sleep disturbance

Insomnia or hypersomnia nearly every day. Insomnia can be sleep onset difficulty, middle-of-the-night awakening, or early morning waking. Hypersomnia involves sleeping substantially more than usual yet still feeling unrested.

5. Psychomotor changes

Psychomotor agitation (restless movement, hand-wringing, inability to sit still) or psychomotor retardation (slowed speech and movement, longer response time) nearly every day. Must be observable by others, not merely subjective feelings of restlessness or slowness.

6. Fatigue

Fatigue or loss of energy nearly every day. Feeling exhausted even after adequate sleep; small tasks requiring substantial effort; reduced productivity and capacity.

7. Worthlessness or guilt

Feelings of worthlessness or excessive or inappropriate guilt (which may be delusional in severe cases) nearly every day. Goes beyond self-reproach about being ill; involves pervasive negative self-evaluation.

8. Cognitive symptoms

Diminished ability to think or concentrate, or indecisiveness, nearly every day, either subjectively reported or observable. Difficulty with reading, working, completing tasks; struggling with decisions that were previously simple.

9. Thoughts of death or suicide

Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide. Any positive response on this criterion warrants immediate professional safety assessment, regardless of total symptom count.

Additional criteria:

The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning
The episode is not attributable to the physiological effects of a substance or another medical condition
The episode is not better explained by schizoaffective disorder, schizophrenia, or other psychotic disorders
There has never been a manic or hypomanic episode (if such an episode has occurred, the diagnosis is Bipolar Disorder, not MDD)

The DSM-5 criteria are diagnostic guidelines used by qualified mental health professionals; meeting symptom criteria suggests further evaluation rather than self-diagnosing. Screening tools like PHQ-9 operationalise these criteria for accessible screening.

Severity grades

DSM-5 specifies three severity grades for MDD based on number of symptoms, severity, and functional impact:

Severity	Criteria	Treatment approach
Mild	Few symptoms in excess of those required, intensity of symptoms manageable, minor functional impact. Often 5-6 symptoms.	Psychotherapy first-line (CBT, behavioural activation); lifestyle measures emphasised; medication if preferred or if symptoms persist.
Moderate	Symptom count and intensity between mild and severe; functional impact substantial but not extreme. Often 6-7 symptoms.	Psychotherapy plus medication often; either alone reasonable in some cases; lifestyle measures continued.
Severe	Many symptoms in excess of those required, intensity seriously distressing and unmanageable, marked functional impact. Often 7+ symptoms or particularly severe specific symptoms.	Medication usually essential; psychotherapy added when tolerated; consider hospitalisation if safety concerns; ECT for severe treatment-resistant or specific situations.

Severity affects treatment selection and intensity but not the diagnostic label. A severe episode is still MDD; severity describes the current presentation. Severity can change across episodes in patients with recurrent MDD.

Severity assessment combines symptom count, individual symptom intensity, and functional impact. A patient with 5 mild symptoms producing minimal functional impact has mild MDD; a patient with 5 severe symptoms producing inability to work or self-care has severe MDD despite same symptom count.

DSM-5 specifiers

DSM-5 includes specifiers describing additional features of MDD episodes. These guide treatment and prognosis. Common specifiers:

With anxious distress

Anxiety symptoms accompanying depression (tension, restlessness, difficulty concentrating due to worry, fear, feeling something terrible may happen). Very common; affects treatment selection (often SSRI with anxiolytic profile).

With mixed features

Some manic or hypomanic symptoms during the depressive episode without meeting full bipolar criteria. Important to identify; standard antidepressants may worsen mixed features.

With melancholic features

Severe anhedonia, lack of mood reactivity (mood does not improve with positive events), early morning waking, worse in morning, marked psychomotor retardation, significant weight loss, excessive guilt. May respond preferentially to certain medications.

With atypical features

Reactive mood (mood improves with positive events), weight gain or increased appetite, hypersomnia, leaden paralysis (heavy feeling in arms or legs), sensitivity to rejection. Sometimes responds preferentially to MAOIs (rarely used in India).

With psychotic features

Delusions or hallucinations alongside depression. Mood-congruent psychotic features have content related to depression themes (worthlessness, guilt, deserved punishment); mood-incongruent features do not. Requires combination antipsychotic plus antidepressant or ECT.

With peripartum onset

Onset during pregnancy or within 4 weeks after delivery (DSM-5 definition; clinically often used for first year postpartum). Specific treatment considerations including breastfeeding compatibility.

With seasonal pattern

Pattern of depressive episodes occurring at characteristic time of year (typically autumn/winter onset with spring/summer remission). May respond to light therapy. Less common in tropical India than northern regions.

With catatonia

Catatonic features including motor immobility, mutism, posturing, negativism. Uncommon but serious; requires specific treatment including benzodiazepines or ECT.

Patients may have multiple specifiers (e.g., severe MDD with anxious distress and melancholic features). Specifiers refine treatment selection and provide prognostic information. Some specifiers (melancholic, atypical, psychotic) particularly influence medication choice.

Course and recurrence patterns

50/70/90%

Recurrence rates after MDD episodes: 50 percent after one episode, 70 percent after two, 90 percent after three. These rates shape treatment duration recommendations and inform long-term management decisions.

MDD course patterns vary substantially across patients. Common patterns:

Single episode. Approximately 50 percent of patients have only one major depressive episode in their lifetime. Single episodes are coded F32 in ICD-10. Treatment typically continues for 6-12 months after acute response, then gradually tapered. Some patients do remarkably well long-term after one well-treated episode.

Recurrent. Approximately 50 percent of patients who experience one episode will have a second; 70 percent of those with two episodes will have a third; 90 percent of those with three episodes will have additional episodes. Coded F33 in ICD-10. Treatment recommendations include longer continuation (often 1-2 years after acute response) and sometimes long-term maintenance treatment, particularly after 3+ episodes.

Chronic. Approximately 20 percent of major depressive episodes become chronic, lasting 2 years or longer without full remission. Chronic episodes often have insidious onset, less obvious triggers, and may be missed for years before diagnosis. Often respond to longer treatment courses with combined modalities.

Time course of typical episode. Untreated episodes typically last 6-12 months on average, with wide individual variation (3 months to several years). With effective treatment, substantial improvement usually occurs within 6-12 weeks. Acute treatment phase (6-12 weeks) targets symptom remission; continuation phase (6-9 months minimum after remission) prevents relapse from the current episode; maintenance phase (longer term, indication-dependent) prevents future episodes.

Inter-episode functioning. Between episodes, most patients return to baseline functioning, though some have residual symptoms or subtle persistent impairments. Inter-episode intervals vary from months to decades. Some patients experience "kindling" effect where episodes become more frequent or severe over time without adequate treatment.

Differential diagnosis

Several conditions present with depression-like symptoms but require different treatment. Careful differential diagnosis is part of any MDD assessment.

Condition	Key distinguishing features
Persistent Depressive Disorder (dysthymia)	Chronic milder depression lasting 2+ years; only 2 of 6 symptoms required; often coexists with MDD episodes (double depression).
Bipolar Disorder	History of manic or hypomanic episodes (elevated/irritable mood, decreased sleep need, racing thoughts, increased activity, risk-taking). Critical to identify; antidepressants alone can destabilise bipolar disorder.
Adjustment Disorder with Depressed Mood	Depressive symptoms within 3 months of identifiable stressor; resolves within 6 months of stressor ending; does not meet full MDD criteria.
Bereavement / complicated grief	Symptoms following major loss; allow positive moments interleaved with sadness; usually allow positive memory recall. Can co-occur with MDD.
Medical conditions	Hypothyroidism, vitamin B12 or D deficiency, anaemia, chronic infections, malignancy, neurological conditions (Parkinson's, dementia, stroke), chronic pain. Medical workup excludes these.
Substance-induced mood disorder	Depression caused by substance use, withdrawal, or medication. Alcohol, cannabis, stimulant withdrawal, corticosteroids, some blood pressure medications, hormonal medications can cause depressive symptoms.
Anxiety disorders	Primary anxiety with secondary mood symptoms, vs primary depression with secondary anxiety. Both common and often coexist. See our GAD guide.
Personality disorders	Borderline personality and others can have depressive features. Pattern of long-standing instability vs discrete episodes helps differentiate.
Psychotic disorders	Depressive symptoms within schizoaffective disorder or schizophrenia. Psychotic features must be present outside depressive episodes for these diagnoses.
Premenstrual Dysphoric Disorder (PMDD)	Severe mood symptoms in luteal phase (1-2 weeks before menstruation), resolving with menstruation. Distinct from MDD by timing pattern.

The medical workup for any new MDD diagnosis typically includes thyroid function tests, vitamin B12 and folate, vitamin D, full blood count, basic metabolic panel, and HbA1c if diabetes suspected. Additional tests if clinical features suggest specific conditions.

MDD vs persistent depressive disorder

MDD and Persistent Depressive Disorder (PDD, formerly dysthymia) are the two main depressive disorders in DSM-5; distinguishing them matters for treatment.

Feature	MDD	PDD (dysthymia)
Duration required	2 weeks minimum	2 years minimum (adults); 1 year (children/adolescents)
Number of symptoms	5 of 9 (including depressed mood or anhedonia)	2 of 6 (depressed mood plus 2 others)
Symptom severity	Often more severe	Often less severe but more persistent
Symptom-free periods allowed	Yes, between episodes	No more than 2 months symptom-free in 2 years
Pattern	Discrete episodes	Chronic baseline
ICD-10 code	F32 (single) or F33 (recurrent)	F34.1
Treatment duration	6-12 months after first episode; longer for recurrent	Often longer; combined therapy often needed

Some patients have both: chronic PDD with superimposed MDD episodes ("double depression"). This presentation is more severe and treatment-resistant than either alone, requiring careful long-term management. PDD is often underrecognised because patients and clinicians may attribute chronic low mood to personality ("just how I am") rather than treatable illness. Effective PDD treatment can produce profound life changes after years or decades of chronic depression.

Common comorbidities

MDD frequently coexists with other conditions; recognising and treating comorbidities is essential for full recovery.

Anxiety disorders. The most common comorbidity; 50 percent or more of MDD patients have a coexisting anxiety disorder (GAD, panic disorder, social anxiety, OCD, PTSD). Anxiety often precedes depression developmentally; both should be treated. SSRIs and SNRIs effective for both. See our anxiety disorders pillar.

Substance use disorders. Alcohol use disorder is particularly common; alcohol initially calms but worsens depression overall and increases suicide risk. Cannabis use, particularly heavy chronic use, associated with worse depression outcomes. Effective MDD treatment usually requires addressing substance use.

Chronic medical conditions. Diabetes, cardiovascular disease, chronic pain, cancer, neurological conditions all show higher rates of comorbid depression. Bidirectional: medical conditions can cause depression; depression worsens medical outcomes. Integrated care addressing both improves outcomes.

Insomnia. Sleep disturbance is both an MDD symptom and an independent contributor. Untreated insomnia worsens depression and reduces treatment response. CBT-I (Cognitive Behavioural Therapy for Insomnia) often valuable alongside MDD treatment. See our sleep and anxiety guide.

Personality disorders. Borderline, avoidant, and dependent personality disorders particularly common with MDD. Both should be addressed; depression treatment alone may produce only partial improvement when personality issues are central.

Eating disorders. Bulimia nervosa, binge eating disorder, and anorexia nervosa show high rates of comorbid depression. Both conditions need treatment.

Prognosis with treatment

MDD prognosis with appropriate treatment is generally good. Realistic expectations:

60-80 percent of patients respond well to first-line treatment (response = 50 percent or greater symptom reduction)
40-60 percent achieve full remission with first-line treatment
Additional patients achieve remission with second-line treatments
10-30 percent develop treatment-resistant patterns requiring specialist approaches
Most patients show some improvement within 4-6 weeks of starting effective treatment
Full benefit typically takes 8-12 weeks
Continuation treatment (6-9 months after acute response) substantially reduces relapse
Long-term maintenance treatment recommended after 3+ episodes
Even severe and chronic MDD typically responds to comprehensive treatment, sometimes including ECT or newer treatments like ketamine/esketamine

Factors associated with better prognosis: shorter duration before treatment, mild-to-moderate severity, absence of psychotic features, good social support, absence of major comorbidities, good treatment engagement. Factors associated with worse prognosis: longer duration of untreated illness, severe presentations, psychotic or melancholic features, comorbid personality disorders or substance use, ongoing severe psychosocial stressors, treatment non-adherence.

Treatment-resistant depression

Treatment-resistant depression (TRD) refers to depression that has not responded adequately to multiple appropriate treatment trials. Most common definition: failure to respond to 2 or more adequate antidepressant trials from different classes, each given at adequate dose for adequate duration (typically 4-6 weeks at therapeutic dose).

Approximately 10-30 percent of MDD patients develop treatment-resistant patterns. TRD risk factors include: comorbid anxiety disorders, substance use, undertreated bipolar disorder misdiagnosed as unipolar depression, ongoing severe psychosocial stressors, atypical depression subtype, longer duration of illness before treatment, and severe presentation.

Treatment options for TRD include:

Optimisation: ensuring adequate dose, adequate duration, treatment adherence, addressing co-occurring conditions
Augmentation: adding lithium, atypical antipsychotics (aripiprazole, olanzapine), thyroid hormone, or other agents to existing antidepressant
Switching: changing to different antidepressant class
Combination antidepressants: using two antidepressants with complementary mechanisms
Intensive psychotherapy: CBT, IPT, or other evidence-based therapies, sometimes alongside medication changes
ECT (electroconvulsive therapy): still the most effective treatment for severe TRD; response rates 70-80 percent; modern ECT under anaesthesia is safe; stigma persists from older portrayals but modern practice is very different
TMS (transcranial magnetic stimulation): non-invasive brain stimulation; FDA-approved for TRD; increasingly available in Indian metros
Ketamine/esketamine: newer rapid-acting options; ketamine IV in specialised settings; esketamine (Spravato) nasal spray approved in some countries
Emerging treatments: psilocybin (research stage), deep brain stimulation (research), other novel approaches

TRD typically requires specialist psychiatric care. Most TRD eventually responds to comprehensive treatment, though may require longer treatment trials and combination approaches. A planned dedicated treatment-resistant depression sub-page will cover this in more detail.

India context

Gender distribution. Women have approximately 2:1 higher rates of MDD than men in India, consistent with global patterns. Indian women face additional gender-based stressors including limited autonomy, gender-based violence, and dowry-related pressures contributing to depression risk.

Age of onset. Peak onset of MDD globally is in early adulthood (20s); first episode can occur at any age. In India, the academic pressure context shifts some onset earlier; significant student depression begins in adolescence in the JEE/NEET preparation context.

Treatment gap. The NMHS identified treatment gaps exceeding 80 percent for common mental disorders including depression in many Indian regions. Most adults with clinical MDD in India do not receive any treatment. Barriers include stigma, lack of awareness that depression is a medical condition, cost concerns, geographic access (mental health specialists concentrated in metros), and cultural attribution of symptoms to weakness or spiritual deficit.

Cultural presentations. Indian patients often present with predominantly physical symptoms (body aches, headaches, fatigue, gastrointestinal complaints) rather than describing low mood directly. This somatic presentation can lead to repeated medical consultations without MDD being identified. Cultural reluctance to discuss emotional difficulties contributes; family-honour considerations may discourage acknowledgement of mental health struggles.

Access landscape. Government mental health services include NIMHANS (Bengaluru), AIIMS Delhi, state mental health institutes, and District Mental Health Programme services. The Mental Healthcare Act 2017 strengthened rights to mental health treatment. Tele-MANAS (national mental health helpline launched 2022) provides 24x7 support. Private psychiatric services widely available in urban centres at varying costs.

For comprehensive India context including detailed treatment access landscape, see the depression and mood disorders pillar.

When to seek help

Professional consultation is appropriate when:

Depressive symptoms have persisted for 2 weeks or longer
Symptoms substantially affect work, relationships, self-care, or daily functioning
Loss of interest in previously enjoyed activities is prominent
Sleep, appetite, or energy changes accompany mood symptoms
Thoughts of self-harm or suicide are present (immediate help; do not wait)
Symptoms recur after previous depression
Self-management measures have not produced improvement after reasonable trial
Depression follows major life events including bereavement, relationship breakdown, job loss
Depression in the postpartum period
Depression alongside chronic medical conditions
Using alcohol or unprescribed substances to manage symptoms
Family or friends have expressed concern about your mood or behaviour
Manic or hypomanic episodes (elevated mood, decreased sleep need, racing thoughts) suggesting bipolar disorder rather than unipolar MDD

First contact can be a GP, psychiatrist, or clinical psychologist. In India, government hospitals (NIMHANS, AIIMS, state mental health institutes) provide free or low-cost services. Tele-MANAS (14416) provides 24x7 mental health support and can guide you to local services.

Red flags warranting medical attention

Active suicidal thoughts with plans or intent; contact crisis helpline or emergency services immediately
Self-harm or suicide attempts
Severe inability to function (cannot work, care for children, manage basic self-care)
Psychotic features (delusions, hallucinations) alongside depression
Manic or hypomanic symptoms suggesting bipolar disorder
Severe weight loss or refusing to eat
Symptoms not responding to 8-12 weeks of appropriate treatment
New onset depression in elderly with cognitive symptoms (consider dementia evaluation)
Depression in postpartum period (specific assessment needed)
Using alcohol, cannabis, or unprescribed substances to manage symptoms
Increasing isolation from family and friends
Symptoms substantially affecting work performance or relationships

A note from Dr. Boppana Sridhar

When patients first come to me with depression, the most useful conversation is usually about what depression actually is. Many Indian patients arrive after months or years of struggling, having been told by well-meaning family that they should pray more, be stronger, or count their blessings; some have been told depression is not a real illness or that it only affects rich people with too much time. Establishing that MDD is a medical condition with specific diagnostic criteria, predictable course patterns, and effective treatments often produces visible relief in the first consultation. The 9 DSM-5 criteria are not arbitrary; they describe a recognisable clinical syndrome that responds to specific treatments. The 50/70/90 percent recurrence statistics matter because they tell us that one episode is not a one-time event for half of patients; planning continuation and sometimes maintenance treatment from the start reduces future suffering. What concerns me most is the treatment gap; NMHS finding that over 80 percent of Indians with depression receive no treatment represents preventable suffering and avoidable suicides. If you recognise yourself in this article, please reach out to a doctor, helpline like Tele-MANAS 14416, or trusted person. The reaching out is the hardest part; once you do, treatment is straightforward for most patients.

Frequently asked questions

What is Major Depressive Disorder?

Major Depressive Disorder (MDD) is a clinical mental health condition characterised by one or more major depressive episodes, each lasting at least 2 weeks, with at least 5 of 9 specific symptoms present nearly every day. Per DSM-5, the symptoms must include either depressed mood or loss of interest or pleasure (anhedonia), and must cause significant distress or impairment in social, occupational, or other important areas of functioning. MDD is one of the most common mental health conditions globally, with WHO estimating depression affects 280 million people worldwide. Lifetime prevalence is approximately 15-20 percent globally and 5.25 percent in India per the National Mental Health Survey. MDD is distinct from other mood disorders including persistent depressive disorder (dysthymia), bipolar disorder, and adjustment disorder. MDD is highly treatable; 60-80 percent of patients respond well to first-line treatment combining psychotherapy, medication, and lifestyle measures.

How is MDD different from feeling sad?

MDD differs from normal sadness in five key ways. Duration: sadness lasts hours to days; MDD persists 2 weeks or longer continuously. Severity: sadness allows continued functioning; MDD substantially impairs work, relationships, and self-care. Symptom breadth: MDD requires 5 of 9 specific symptoms across mood, cognitive, physical, and behavioural domains; sadness typically involves only the emotional dimension. Response to events: sadness improves with positive events; MDD persists despite positive circumstances. Distortion of thinking: MDD involves persistent negative thinking patterns (worthlessness, hopelessness, sometimes suicidal thoughts) that do not respond to reassurance. The clinical distinction matters because MDD typically does not resolve without active treatment, while sadness usually does. If symptoms have lasted 2 weeks or longer and substantially affect daily functioning, professional assessment is appropriate regardless of whether the experience feels like depression or like deep sadness.

What are the 9 DSM-5 criteria for MDD?

DSM-5 lists 9 symptoms for Major Depressive Disorder; 5 must be present nearly every day for 2 weeks or longer, with at least one being depressed mood or loss of interest. The 9 symptoms: 1) Depressed mood most of the day, nearly every day (subjective or observed). 2) Markedly diminished interest or pleasure in all or most activities (anhedonia). 3) Significant weight loss when not dieting or weight gain (more than 5 percent body weight change in a month) or decrease/increase in appetite. 4) Insomnia or hypersomnia nearly every day. 5) Psychomotor agitation or retardation observable by others. 6) Fatigue or loss of energy nearly every day. 7) Feelings of worthlessness or excessive/inappropriate guilt. 8) Diminished ability to think or concentrate, or indecisiveness. 9) Recurrent thoughts of death, recurrent suicidal ideation without a specific plan, or a suicide attempt or specific plan. Additional criteria: symptoms cause clinically significant distress or functional impairment; episode is not attributable to substances or medical condition; episode is not better explained by another psychiatric disorder.

How long does a depressive episode last?

Untreated major depressive episodes typically last 6-12 months on average, though the range is wide: some episodes resolve within 3 months, others persist for years. With effective treatment, most episodes show substantial improvement within 6-12 weeks and remission within 6 months. Approximately 20 percent of untreated episodes become chronic, lasting 2 years or longer. The natural course varies based on factors including severity, age of onset, comorbid conditions, social support, life circumstances, and access to treatment. After a first episode, approximately 50 percent of patients will have a second episode within their lifetime; after a second episode, 70 percent will have a third; after a third episode, 90 percent will have another. This recurrent pattern is why continuation treatment (6-9 months after acute response) and sometimes long-term maintenance treatment are recommended. Early effective treatment reduces duration of the current episode and may reduce risk of future episodes.

What is the difference between MDD and persistent depressive disorder?

MDD and Persistent Depressive Disorder (PDD, formerly dysthymia) are related but distinct conditions. MDD involves discrete episodes of severe depressive symptoms (5 of 9 symptoms) lasting at least 2 weeks; between episodes the person typically returns to baseline functioning. PDD involves chronic, less severe depressive symptoms persisting for at least 2 years (1 year in children and adolescents), with only 2 of 6 symptoms required (depressed mood plus 2 others), and symptom-free periods cannot exceed 2 months. Some patients have both: chronic PDD with superimposed MDD episodes (sometimes called 'double depression'), which is more severe and treatment-resistant than either alone. Treatment principles overlap (psychotherapy, antidepressants, lifestyle measures) but PDD often requires longer treatment duration and combined approaches. PDD is ICD-10 F34.1; MDD is F32 (single episode) or F33 (recurrent). Distinguishing the two matters because PDD is often underrecognised as patients and clinicians may attribute chronic low mood to personality rather than treatable illness.

Can MDD go away on its own?

Some major depressive episodes resolve without active treatment, though this is not the typical pattern and waiting carries substantial costs. Approximately 20-40 percent of untreated depressive episodes resolve within 3-6 months; the remaining majority persist longer or become chronic. Even when episodes resolve spontaneously, untreated depression carries risks: functional impairment during the episode (work, relationships, education), suicide risk that increases with episode severity, worsening of comorbid conditions (diabetes, cardiovascular disease, substance use), and higher risk of future episodes that may be more severe or treatment-resistant. The honest framing: treatment substantially reduces duration and severity of episodes, reduces recurrence risk, and reduces functional impairment during the episode. Even mild MDD typically benefits from treatment when symptoms have lasted several weeks. Waiting for spontaneous remission is reasonable only for very mild brief presentations clearly tied to identifiable temporary stressors. For most patients with MDD, active treatment is the better choice.

What is treatment-resistant depression?

Treatment-resistant depression (TRD) refers to depression that has not responded adequately to multiple appropriate treatment trials. Definitions vary; the most common: failure to respond to 2 or more adequate trials of antidepressant medications from different classes, each tried at adequate dose for adequate duration (typically 4-6 weeks). Approximately 10-30 percent of patients with MDD develop treatment-resistant patterns. Factors associated with TRD include: comorbid anxiety disorders, substance use, chronic medical conditions, untreated bipolar disorder misdiagnosed as unipolar depression, ongoing severe psychosocial stressors, atypical depression subtype, and longer duration of illness before treatment. Treatment options for TRD include: optimisation (higher doses, longer trials), augmentation (adding lithium, atypical antipsychotics, thyroid hormone, or other agents), switching to different antidepressant classes, intensive psychotherapy, ECT (electroconvulsive therapy, still highly effective for severe TRD), TMS (transcranial magnetic stimulation, increasingly available in India), ketamine/esketamine (newer rapid-acting options), and emerging treatments. TRD requires specialist psychiatric care; most TRD eventually responds to comprehensive treatment.

How common is MDD in India?

The National Mental Health Survey of India (NMHS, 2015-16, conducted by NIMHANS) estimated lifetime prevalence of depressive disorders at approximately 5.25 percent in Indian adults, with current prevalence around 2.7 percent. This is lower than global estimates (15-20 percent lifetime globally) which may reflect genuine epidemiological differences, methodological factors including stigma affecting reporting, or cultural variations in how depression is recognised and expressed. Within India, prevalence varies by region, urban/rural status, and demographic factors. Women have approximately twice the rate of MDD as men, consistent with global patterns. Specific Indian high-risk groups include students facing competitive exam pressure (JEE, NEET, board exams), postpartum women (11-22 percent depending on study), elderly experiencing social isolation and chronic illness, agricultural communities under economic stress, and those affected by gender-based violence or discrimination. The treatment gap exceeds 80 percent in many regions, meaning most Indian adults with clinical depression do not receive any treatment. Tele-MANAS (14416), launched 2022, has substantially expanded access to mental health support.

Medical disclaimer: This article provides general health education and does not replace personalised consultation with a qualified mental health professional. MDD requires individual clinical assessment for accurate diagnosis and appropriate treatment planning. If you are experiencing severe symptoms or thoughts of self-harm, contact a crisis helpline or emergency services immediately.

About the author

247healthcare.blog editorial team writes general health and preventive medicine content reviewed by qualified doctors. Every article is fact-checked against current guidance from DSM-5, ICD-10/11, NICE NG222, APA, WHO, NMHS NIMHANS, Cochrane reviews, and peer-reviewed mood disorders literature before publication.

About the medical reviewer

Dr. Boppana Sridhar (MBBS, MD Psychiatry, Australia-trained) is the Consultant Psychiatrist and department lead for Psychiatry and Psychology at Vivekananda Hospital, Begumpet, Hyderabad. He has 9+ years of clinical experience in diagnosing and treating Major Depressive Disorder across mild-to-severe presentations including melancholic and atypical subtypes, comorbid presentations, perinatal depression, and treatment-resistant cases. NMC-registered.