Editing Major depressive disorder (section)

==Diagnosis==

===Assessment===
{{further|Rating scales for depression}}
[[File:A wretched man with an approaching depression; represented b Wellcome V0011145.jpg|thumb|left|Caricature of a man with depression]]
A diagnostic assessment may be conducted by a suitably trained [[general practitioner]], or by a [[psychiatrist]] or [[psychologist]],<ref name=NIMHPub/> who [[psychiatric history|records]] the person's current circumstances, biographical history, current symptoms, family history, and alcohol and drug use. The assessment also includes a [[mental state examination]], which is an assessment of the person's current mood and thought content, in particular the presence of themes of hopelessness or [[pessimism]], [[self-harm]] or suicide, and an absence of positive thoughts or plans.<ref name=NIMHPub/> Specialist mental health services are rare in rural areas, and thus diagnosis and management is left largely to [[primary care|primary-care]] clinicians.<ref>{{cite journal |vauthors=Kaufmann IM |title=Rural psychiatric services. A collaborative model |journal=Canadian Family Physician |volume=39 |pages=1957–1961 |year=1993 |pmid=8219844 |pmc=2379905 }}</ref> This issue is even more marked in developing countries.<ref>{{cite web |url=http://news.bbc.co.uk/1/hi/health/492941.stm |title=Call for action over Third World depression |access-date=11 October 2008 |date=1 November 1999 |website=BBC News (Health) |publisher=British Broadcasting Corporation (BBC) |url-status=live |archive-url=https://web.archive.org/web/20080513222415/http://news.bbc.co.uk/1/hi/health/492941.stm |archive-date=13 May 2008 }}</ref> [[Rating scale]]s are not used to diagnose depression, but they provide an indication of the severity of symptoms for a time period, so a person who scores above a given cut-off point can be more thoroughly evaluated for a depressive disorder diagnosis. Several rating scales are used for this purpose;<ref>{{cite journal |vauthors=Sharp LK, Lipsky MS |title=Screening for depression across the lifespan: a review of measures for use in primary care settings |journal=American Family Physician |volume=66 |issue=6 |pages=1001–08 |date=September 2002 |pmid=12358212 }}</ref><!-- cites two previous sentences --> these include the [[Hamilton Rating Scale for Depression]],<ref>{{cite journal |vauthors=Zimmerman M, Chelminski I, Posternak M |title=A review of studies of the Hamilton depression rating scale in healthy controls: implications for the definition of remission in treatment studies of depression |journal=The Journal of Nervous and Mental Disease |volume=192 |issue=9 |pages=595–601 |date=September 2004 |pmid=15348975 |doi=10.1097/01.nmd.0000138226.22761.39 |s2cid=24291799 }}</ref> the [[Beck Depression Inventory]]<ref>{{cite journal |vauthors=McPherson A, Martin CR |title=A narrative review of the Beck Depression Inventory (BDI) and implications for its use in an alcohol-dependent population |journal=Journal of Psychiatric and Mental Health Nursing |volume=17 |issue=1 |pages=19–30 |date=February 2010 |pmid=20100303 |doi=10.1111/j.1365-2850.2009.01469.x }}</ref> or the [[Suicide Behaviors Questionnaire-Revised]].<ref>{{cite journal |vauthors=Osman A, Bagge CL, Gutierrez PM, Konick LC, Kopper BA, Barrios FX |title=The Suicidal Behaviors Questionnaire-Revised (SBQ-R): validation with clinical and nonclinical samples |journal=Assessment |volume=8 |issue=4 |pages=443–54 |date=December 2001 |pmid=11785588 |doi=10.1177/107319110100800409 |s2cid=11477277 }}</ref>

[[Primary-care physician]]s have more difficulty with underrecognition and undertreatment of depression compared to psychiatrists. These cases may be missed because for some people with depression, [[#physicalSymptoms|physical symptoms]] often accompany depression. In addition, there may also be barriers related to the person, provider, and/or the medical system. Non-psychiatrist physicians have been shown to miss about two-thirds of cases, although there is some evidence of improvement in the number of missed cases.<ref>{{cite journal |vauthors=Cepoiu M, McCusker J, Cole MG, Sewitch M, Belzile E, Ciampi A |title=Recognition of depression by non-psychiatric physicians—a systematic literature review and meta-analysis |journal=Journal of General Internal Medicine |volume=23 |issue=1 |pages=25–36 |date=January 2008 |pmid=17968628 |pmc=2173927 |doi=10.1007/s11606-007-0428-5 }}</ref>

A doctor generally performs a medical examination and selected investigations to rule out other causes of depressive symptoms. These include blood tests measuring [[Thyroid-stimulating hormone|TSH]] and [[thyroxine]] to exclude [[hypothyroidism]]; [[Blood tests#Biochemical analysis|basic electrolytes]] and serum [[calcium]] to rule out a [[Metabolic disorder|metabolic disturbance]]; and a [[Complete blood count|full blood count]] including [[Erythrocyte sedimentation rate|ESR]] to rule out a [[systemic infection]] or chronic disease.<ref>{{cite journal |vauthors=Dale J, Sorour E, Milner G |year=2008 |title=Do psychiatrists perform appropriate physical investigations for their patients? A review of current practices in a general psychiatric inpatient and outpatient setting |journal=Journal of Mental Health |volume=17 |issue=3 |pages=293–98|doi=10.1080/09638230701498325|s2cid=72755878 }}</ref> Adverse affective reactions to medications or alcohol misuse may be ruled out, as well. [[Testosterone]] levels may be evaluated to diagnose [[hypogonadism]], a cause of depression in men.<ref>{{cite journal |vauthors=Orengo CA, Fullerton G, Tan R |title=Male depression: a review of gender concerns and testosterone therapy |journal=Geriatrics |volume=59 |issue=10 |pages=24–30 |date=October 2004 |pmid=15508552 }}</ref> [[Vitamin D]] levels might be evaluated, as low levels of vitamin D have been associated with greater risk for depression.<ref name=Parker2017/> Subjective cognitive complaints appear in older depressed people, but they can also be indicative of the onset of a [[dementia|dementing disorder]], such as [[Alzheimer's disease]].<ref>{{cite journal |vauthors=Reid LM, Maclullich AM |title=Subjective memory complaints and cognitive impairment in older people |journal=Dementia and Geriatric Cognitive Disorders |volume=22 |issue=5–6 |pages=471–85 |year=2006 |pmid=17047326 |doi=10.1159/000096295 |s2cid=9328852 }}</ref><ref>{{cite journal |vauthors=Katz IR |title=Diagnosis and treatment of depression in patients with Alzheimer's disease and other dementias |journal=The Journal of Clinical Psychiatry |volume=59 |issue=Suppl 9 |pages=38–44 |year=1998 |pmid=9720486 }}</ref> [[Neuropsychological assessment|Cognitive testing]] and brain imaging can help distinguish depression from dementia.<ref>{{cite journal |vauthors=Wright SL, Persad C |title=Distinguishing between depression and dementia in older persons: neuropsychological and neuropathological correlates |journal=Journal of Geriatric Psychiatry and Neurology |volume=20 |issue=4 |pages=189–98 |date=December 2007 |pmid=18004006 |doi=10.1177/0891988707308801 |s2cid=33714179 }}</ref> A [[CT scan]] can exclude brain pathology in those with psychotic, rapid-onset or otherwise unusual symptoms.<ref>{{Harvnb |Sadock|2002|p=108}}</ref> No biological tests confirm major depression.<ref>{{Harvnb |Sadock|2002|p=260}}</ref> In general, investigations are not repeated for a subsequent episode unless there is a medical [[Indication (medicine)|indication]].

===DSM and ICD criteria===
The most widely used criteria for diagnosing depressive conditions are found in the [[American Psychiatric Association]]'s ''[[Diagnostic and Statistical Manual of Mental Disorders]]'' (DSM) and the [[World Health Organization]]'s ''[[ICD|International Statistical Classification of Diseases and Related Health Problems]]'' (ICD). The latter system is typically used in European countries, while the former is used in the US and many other non-European nations,<ref>{{Harvnb |Sadock|2002|p=288}}</ref> and the authors of both have worked towards conforming one with the other.{{sfn|American Psychiatric Association|2013|p=xii}} Both DSM and ICD mark out typical (main) depressive symptoms.<ref name="DSMvsICD" /> The most recent edition of the DSM is the Fifth Edition, Text Revision (DSM-5-TR),<ref>{{cite web |title=Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) |url=https://psychiatry.org/psychiatrists/practice/dsm |website=American Psychiatric Association |access-date=9 July 2022 |quote=The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) features the most current text updates based on scientific literature with contributions from more than 200 subject matter experts.}}</ref> and the most recent edition of the ICD is the Eleventh Edition (ICD-11).<ref>{{cite web |title=International Statistical Classification of Diseases and Related Health Problems (ICD) |url=https://www.who.int/standards/classifications/classification-of-diseases |website=World Health Organization |access-date=9 July 2022 |quote=... the latest version of the ICD, ICD-11, was adopted by the 72nd World Health Assembly in 2019 and came into effect on 1st January 2022.}}</ref>

Under mood disorders, ICD-11 classifies major depressive disorder as either ''single episode depressive disorder'' (where there is no history of depressive episodes, or of [[mania]]) or ''recurrent depressive disorder'' (where there is a history of prior episodes, with no history of mania).<ref name="ICD11 6A70 and 6A71">ICD-11, [[#CITEREF-ICD11-6A70|6A70 Single episode depressive disorder]] and [[#CITEREF-ICD11-6A71|6A71 Recurrent depressive disorder]]</ref> ICD-11 symptoms, present nearly every day for at least two weeks, are a depressed mood or [[anhedonia]], accompanied by other symptoms such as "difficulty concentrating, feelings of worthlessness or excessive or inappropriate guilt, hopelessness, recurrent thoughts of death or suicide, changes in appetite or sleep, psychomotor agitation or retardation, and reduced energy or fatigue."<ref name="ICD11 6A70 and 6A71"/> These symptoms must affect work, social, or domestic activities. The ICD-11 system allows further specifiers for the current depressive episode: the severity (mild, moderate, severe, unspecified); the presence of psychotic symptoms (with or without psychotic symptoms); and the degree of remission if relevant (currently in partial remission, currently in full remission).<ref name="ICD11 6A70 and 6A71"/> These two disorders are classified as "Depressive disorders", in the category of "Mood disorders".<ref name="ICD11 6A70 and 6A71"/>

According to DSM-5, at least one of the symptoms is either depressed mood or loss of interest or pleasure. Depressed mood occurs nearly every day as subjective feelings like sadness, emptiness, and hopelessness or observations made by others (e.g. appears tearful). Loss of interest or pleasure occurs in all, or almost all activities of the day, nearly every day. These symptoms, as well as five out of the nine more specific symptoms listed, must frequently occur for more than two weeks (to the extent in which it impairs functioning) for the diagnosis.<ref>{{cite book |title=Diagnostic and statistical manual of mental disorders: DSM-5 |date=2013 |publisher=American psychiatric association |location=Washington |isbn=978-0-89042-554-1 |edition=5th}}</ref><ref>{{Cite web |url=https://www.psnpaloalto.com/wp/wp-content/uploads/2010/12/Depression-Diagnostic-Criteria-and-Severity-Rating.pdf|title=Diagnostic Criteria for Major Depressive Disorder and Depressive Episodes |website=City of Palo Alto Project Safety Net |access-date=21 February 2019|archive-date=3 August 2020|url-status=usurped|archive-url=https://web.archive.org/web/20200803161533/https://www.psnpaloalto.com/wp/wp-content/uploads/2010/12/Depression-Diagnostic-Criteria-and-Severity-Rating.pdf}}</ref>{{Failed verification|date=July 2022|reason=This source was written before DSM-5 was finalised, and only talks about proposed DSM-5 symptoms.}} Major depressive disorder is classified as a mood disorder in the DSM-5.<ref name=Parker2014>{{Cite journal|vauthors=Parker GF|date=1 June 2014|title=DSM-5 and Psychotic and Mood Disorders|url=http://jaapl.org/content/42/2/182|journal=Journal of the American Academy of Psychiatry and the Law Online|language=en|volume=42|issue=2|pages=182–190|issn=1093-6793|pmid=24986345}}</ref> The diagnosis hinges on the presence of single or recurrent [[major depressive episode]]s.<ref name=APA162>{{Harvnb |American Psychiatric Association|2013|p=162}}</ref> Further qualifiers are used to classify both the episode itself and the course of the disorder. The category [[Depressive Disorder Not Otherwise Specified|Unspecified Depressive Disorder]] is diagnosed if the depressive episode's manifestation does not meet the criteria for a major depressive episode.<ref name=Parker2014/>

====Major depressive episode====
{{Main|Major depressive episode}}
A major depressive episode is characterized by the presence of a severely depressed mood that persists for at least two weeks.<ref name="b502">{{cite book |last1=Black |first1=Donald W. |last2=Andreasen |first2=Nancy C. |title=Introductory Textbook of Psychiatry |publisher=American Psychiatric Pub |publication-place=Washington, DC |date=4 May 2020 |isbn=978-1-61537-318-5 |chapter=Mood Disorders}}</ref> Episodes may be isolated or recurrent and are categorized as mild (few symptoms in excess of minimum criteria), moderate, or severe (marked impact on social or occupational functioning). An episode with psychotic features—commonly referred to as ''[[psychotic depression]]''—is automatically rated as severe.<ref name=Parker2014/> If the person has had an episode of [[mania]] or [[hypomania|markedly elevated mood]], a diagnosis of [[bipolar disorder]] is made instead. Depression without mania is sometimes referred to as ''unipolar'' because the mood remains at one emotional state or "pole".<ref>{{Harvnb |Parker|1996|p=173}}</ref>

[[Grief|Bereavement]] is not an exclusion criterion in the DSM-5, and it is up to the clinician to distinguish between normal reactions to a loss and MDD. Excluded are a range of related diagnoses, including [[dysthymia]], which involves a chronic but milder mood disturbance;<ref name=Sadock552>{{Harvnb |Sadock|2002|p=552}}</ref> [[recurrent brief depression]], consisting of briefer depressive episodes;{{sfn|American Psychiatric Association|2013|p=183}}<ref>{{cite journal |vauthors=Carta MG, Altamura AC, Hardoy MC, Pinna F, Medda S, Dell'Osso L, Carpiniello B, Angst J |title=Is recurrent brief depression an expression of mood spectrum disorders in young people? Results of a large community sample |journal=European Archives of Psychiatry and Clinical Neuroscience |volume=253 |issue=3 |pages=149–53 |date=June 2003 |pmid=12904979 |doi=10.1007/s00406-003-0418-5 |hdl=2434/521599 |s2cid=26860606 |hdl-access=free }}</ref> [[minor depressive disorder]], whereby only some symptoms of major depression are present;<ref>{{cite journal |vauthors=Rapaport MH, Judd LL, Schettler PJ, Yonkers KA, Thase ME, Kupfer DJ, Frank E, Plewes JM, Tollefson GD, Rush AJ |title=A descriptive analysis of minor depression |journal=The American Journal of Psychiatry |volume=159 |issue=4 |pages=637–43 |date=April 2002 |pmid=11925303 |doi=10.1176/appi.ajp.159.4.637 }}</ref> and [[Adjustment disorder|adjustment disorder with depressed mood]], which denotes low mood resulting from a psychological response to an identifiable event or [[Stress (biological)|stressor]].{{sfn|American Psychiatric Association|2013|p=168}}

====Subtypes====
The DSM-5 recognizes six further subtypes of MDD, called ''specifiers'', in addition to noting the length, severity and presence of psychotic features:
* "[[Melancholic depression]]" is characterized by a loss of pleasure in most or all activities, a failure of reactivity to pleasurable stimuli, a quality of depressed mood more pronounced than that of [[grief]] or loss, a worsening of symptoms in the morning hours, early-morning waking, [[psychomotor retardation]], excessive weight loss (not to be confused with [[anorexia nervosa]]), or excessive guilt.<ref name="g379"/>
* "[[Atypical depression]]" is characterized by mood reactivity (paradoxical anhedonia) and positivity, significant [[weight gain]] or increased appetite (comfort eating), excessive sleep or sleepiness ([[hypersomnia]]), a sensation of heaviness in limbs known as leaden paralysis, and significant long-term social impairment as a consequence of hypersensitivity to perceived [[social rejection|interpersonal rejection]].{{sfn|American Psychiatric Association|2013|pp=185–186}}
* "[[Catatonic depression]]" is a rare and severe form of major depression involving disturbances of motor behavior and other symptoms. Here, the person is mute and almost stuporous, and either remains immobile or exhibits purposeless or even bizarre movements. Catatonic symptoms also occur in [[schizophrenia]] or in manic episodes, or may be caused by [[neuroleptic malignant syndrome]].{{sfn|American Psychiatric Association|2013|pp=119–120}}
* "Depression with [[Anxiety|anxious]] distress" was added into the DSM-5 as a means to emphasize the common co-occurrence between depression and anxiety, as well as the risk of suicide of depressed individuals with anxiety.<ref name="t660">{{cite journal | last=Hopwood | first=Malcolm | title=Anxiety Symptoms in Patients with Major Depressive Disorder: Commentary on Prevalence and Clinical Implications | journal=Neurology and Therapy | volume=12 | issue=S1 | date=2023 | issn=2193-8253 | pmid=37115459 | pmc=10141876 | doi=10.1007/s40120-023-00469-6 | doi-access=free | pages=5–12 | url=https://link.springer.com/content/pdf/10.1007/s40120-023-00469-6.pdf | access-date=6 March 2025}}</ref>
* "Depression with [[Postpartum depression|peri-partum]] onset" refers to the intense, sustained and sometimes disabling depression experienced by women after giving birth or while a woman is pregnant. DSM-IV-TR used the classification "postpartum depression", but this was changed to not exclude cases of depressed woman during pregnancy. Depression with peripartum onset has an incidence rate of 3–6% among new mothers. The DSM-5 mandates that to qualify as depression with peripartum onset, onset occurs during pregnancy or within one month of delivery.{{sfn|American Psychiatric Association|2013|pp=186–187}}<!-- cites paragraph -->
* "[[Seasonal affective disorder]]" (SAD) is a form of depression in which depressive episodes come on in the autumn or winter, and resolve in spring. The diagnosis is made if at least two episodes have occurred in colder months with none at other times, over a two-year period or longer.{{sfn|American Psychiatric Association|2013|p=187}}

===Differential diagnoses===
{{Main|Differential diagnoses of depression}}

To confirm major depressive disorder as the most likely diagnosis, other [[Differential diagnosis|potential diagnoses]] must be considered, including [[dysthymia]], [[adjustment disorder]] with depressed mood, or [[bipolar disorder]]. Dysthymia is a chronic, milder mood disturbance in which a person reports a low mood almost daily over a span of at least two years. The symptoms are not as severe as those for major depression, although people with dysthymia are vulnerable to secondary episodes of major depression (sometimes referred to as ''[[double depression]]'').<ref name=Sadock552/> [[Adjustment disorder|Adjustment disorder with depressed mood]] is a mood disturbance appearing as a psychological response to an identifiable event or stressor, in which the resulting emotional or behavioral symptoms are significant but do not meet the criteria for a major depressive episode.{{sfn|American Psychiatric Association|2013|p=168}}

Other disorders need to be ruled out before diagnosing major depressive disorder. They include depressions due to physical illness, [[medications]], and [[substance use disorder]]s. Depression due to physical illness is diagnosed as a [[Mood disorder#Due to another medical condition|mood disorder due to a general medical condition]]. This condition is determined based on history, laboratory findings, or [[physical examination]]. When the depression is caused by a medication, non-medical use of a psychoactive substance, or exposure to a [[toxin]], it is then diagnosed as a specific mood disorder (previously called ''substance-induced mood disorder'').{{sfn|American_Psychiatric_Association|2013|p=167}}