Editing Major depressive disorder (section)

==Epidemiology==
{{Main|Epidemiology of depression}}
[[File:Unipolar depressive disorders world map - DALY - WHO2004.svg|thumb|upright=1.15|[[Disability-adjusted life year]] for unipolar depressive disorders per 100,000 inhabitants in 2004:<ref>{{cite web |url=https://www.who.int/healthinfo/global_burden_disease/estimates_country/en/index.html |title=WHO Disease and injury country estimates |year=2009 |website=World Health Organization |access-date=11 November 2009 |url-status=live |archive-url=https://web.archive.org/web/20091111101009/http://www.who.int/healthinfo/global_burden_disease/estimates_country/en/index.html |archive-date=11 November 2009 }}</ref>
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Major depressive disorder affected approximately 163&nbsp;million people in 2017 (2% of the global population).<ref name="GBD 2017 prevalence">{{cite journal |author=((GBD 2017 Disease and Injury Incidence and Prevalence Collaborators)) |date=10 November 2018 |title=Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017 |journal=Lancet |volume=392 |issue=10159 |pages=1789–1858 |doi=10.1016/S0140-6736(18)32279-7 |pmc=6227754 |pmid=30496104}}</ref> The percentage of people who are affected at one point in their life varies from 7% in Japan to 21% in France. In most countries the number of people who have depression during their lives falls within an 8–18% range. Lifetime rates are higher in the [[developed world]] (15%) compared to the [[developing world]] (11%).<ref name="Kes2013" />

In the United States, 8.4% of adults (21&nbsp;million individuals) have at least one episode within a year-long period; the probability of having a major depressive episode is higher for females than males (10.5% to 6.2%), and highest for those aged 18 to 25 (17%).<ref name= NIMHMajorDepression>{{cite web |url= https://www.nimh.nih.gov/health/statistics/major-depression |publisher= U.S. [[National Institute of Mental Health]] (NIMH) |date= January 2022 |title= Major depression |archive-url=https://web.archive.org/web/20220809144808/https://www.nimh.nih.gov/health/statistics/major-depression |archive-date= 9 August 2022 |access-date= 14 August 2022}} {{Pd-notice}}</ref> 15% of adolescents, ages 12 to 17, in America are also affected by depression, which is equal to 3.7 million teenagers.<ref name="DP">{{Cite web |title=Depression |url=https://mhanational.org/conditions/depression |access-date=23 June 2024 |website=Mental Health America |language=en}}</ref> Among individuals reporting two or more races, the US prevalence is highest.<ref name=NIMHMajorDepression/> Out of all the people suffering from MDD, only about 35% seek help from a professional for their disorder.<ref name="DP" />

Major depression is about twice as common in women as in men, although it is unclear why this is so, and whether factors unaccounted for are contributing to this.<ref name="Kuehner03">{{cite journal |vauthors=Kuehner C |title=Gender differences in unipolar depression: an update of epidemiological findings and possible explanations |journal=Acta Psychiatrica Scandinavica |volume=108 |issue=3 |pages=163–74 |date=September 2003 |pmid=12890270 |doi=10.1034/j.1600-0447.2003.00204.x |s2cid=19538251}}</ref> The relative increase in occurrence is related to pubertal development rather than chronological age, reaches adult ratios between the ages of 15 and 18, and appears associated with psychosocial more than hormonal factors.<ref name="Kuehner03" /> In 2019, major depressive disorder was identified (using either the DSM-IV-TR or ICD-10) in the [[Global Burden of Disease Study]] as the fifth most common cause of [[years lived with disability]] and the 18th most common for [[disability-adjusted life years]].<ref>{{citation |author=Institute for Health Metrics and Evaluation |author-link=Institute for Health Metrics and Evaluation |year=2020 |title=Global Burden of Disease 2019 Cause and Risk Summary: Major depressive disorder — Level 4 cause |at=Table 3 |url=https://www.healthdata.org/results/gbd_summaries/2019/major-depressive-disorder-level-4-cause |publisher=University of Washington |place=Seattle, US |access-date=9 July 2022}}</ref><!-- the wording of this sentence is very janky, but this best mimics the source. -->

People are most likely to develop their first depressive episode between the ages of 30 and 40, and there is a second, smaller peak of incidence between ages 50 and 60.<ref>{{cite journal |vauthors=Eaton WW, Anthony JC, Gallo J, et al |title=Natural history of Diagnostic Interview Schedule/DSM-IV major depression. The Baltimore Epidemiologic Catchment Area follow-up |journal=Archives of General Psychiatry |volume=54 |issue=11 |pages=993–99 |date=November 1997 |pmid=9366655 |doi=10.1001/archpsyc.1997.01830230023003 }}</ref> The risk of major depression is increased with neurological conditions such as [[stroke]], [[Parkinson's disease]], or [[multiple sclerosis]], and during the first year after childbirth ([[Postpartum depression]]).<ref>{{cite journal |vauthors=Rickards H |title=Depression in neurological disorders: Parkinson's disease, multiple sclerosis, and stroke |journal=Journal of Neurology, Neurosurgery, and Psychiatry |volume=76 |issue=Suppl 1 |pages=i48–52 |date=March 2005 |pmid=15718222 |pmc=1765679 |doi=10.1136/jnnp.2004.060426}}</ref> It is also more common after cardiovascular illnesses, and is related more to those with a poor cardiac [[Prognosis|disease outcome]] than to a better one.<ref>{{cite journal |vauthors=Alboni P, Favaron E, Paparella N, Sciammarella M, Pedaci M |title=Is there an association between depression and cardiovascular mortality or sudden death? |journal=Journal of Cardiovascular Medicine |volume=9 |issue=4 |pages=356–62 |date=April 2008 |pmid=18334889 |doi=10.2459/JCM.0b013e3282785240 |s2cid=11051637 }}</ref><ref>{{cite journal |vauthors=Strik JJ, Honig A, Maes M |title=Depression and myocardial infarction: relationship between heart and mind |journal=Progress in Neuro-Psychopharmacology & Biological Psychiatry |volume=25 |issue=4 |pages=879–92 |date=May 2001 |pmid=11383983 |doi=10.1016/S0278-5846(01)00150-6 |s2cid=45722423 }}</ref> Depressive disorders are more common in urban populations than in rural ones and the prevalence is increased in groups with poorer socioeconomic factors, e.g., homelessness.<ref>Gelder, M, Mayou, R and Geddes, J (2005). ''Psychiatry''. 3rd ed. New York: Oxford. p. 105.</ref> Depression is common among those over 65 years of age and increases in frequency beyond this age.<ref name="SBU">{{Cite web |website=[[Swedish Agency for Health Technology Assessment and Assessment of Social Services]] (SBU) |date=27 January 2015 |title=Depression treatment for the elderly |url=http://www.sbu.se/en/publications/sbu-assesses/depression-treatment-for-the-elderly/ |url-status=live |archive-url=https://web.archive.org/web/20160618011954/http://www.sbu.se/en/publications/sbu-assesses/depression-treatment-for-the-elderly/ |archive-date=18 June 2016 |access-date=16 June 2016}}</ref> The risk of depression increases in relation to the [[Frailty syndrome|frailty]] of the individual.<ref>{{cite journal |vauthors=Soysal P, Veronese N, Thompson, et al |date=July 2017 |title=Relationship between depression and frailty in older adults: A systematic review and meta-analysis |url=http://www.repositorio.ufc.br/handle/riufc/25064 |journal=Ageing Res Rev |volume=36 |pages=78–87 |doi=10.1016/j.arr.2017.03.005 |pmid=28366616 |s2cid=205668529}}</ref> Depression is one of the most important factors which negatively impact quality of life in adults, as well as the elderly.<ref name="SBU" /> Both symptoms and treatment among the elderly differ from those of the rest of the population.<ref name="SBU" />

Major depression was the leading cause of [[disease burden]] in North America and other high-income countries, and the fourth-leading cause worldwide as of 2006. In the year 2030, it is predicted to be the second-leading cause of disease burden worldwide after [[HIV]], according to the WHO.<ref>{{cite journal |vauthors=Mathers CD, Loncar D |title=Projections of global mortality and burden of disease from 2002 to 2030 |journal=PLOS Medicine |volume=3 |issue=11 |page=e442 |date=November 2006 |pmid=17132052 |pmc=1664601 |doi=10.1371/journal.pmed.0030442 |doi-access=free }}</ref> Delay or failure in seeking treatment after relapse and the failure of health professionals to provide treatment are two barriers to reducing disability.<ref>{{cite journal |vauthors=Andrews G |title=Reducing the burden of depression |journal=Canadian Journal of Psychiatry |volume=53 |issue=7 |pages=420–27 |date=July 2008 |pmid=18674396 |doi=10.1177/070674370805300703|doi-access=free }}</ref>

===Comorbidity===
Major depression frequently [[Comorbidity|co-occurs]] with other psychiatric problems. The 1990–92 ''[[National Comorbidity Survey]]'' (US) reported that half of those with major depression also have lifetime [[anxiety]] and its associated disorders, such as [[generalized anxiety disorder]].<ref>{{cite journal |vauthors=Kessler RC, Nelson CB, McGonagle KA, et al|title=Comorbidity of DSM-III-R major depressive disorder in the general population: results from the US National Comorbidity Survey |journal=The British Journal of Psychiatry. Supplement |volume=168 |issue=30 |pages=17–30 |date=June 1996 |pmid=8864145 |doi=10.1192/S0007125000298371 |s2cid=19525295 }}</ref> Anxiety symptoms can have a major impact on the course of a depressive illness, with delayed recovery, increased risk of relapse, greater disability and increased suicidal behavior.<ref>{{cite journal |vauthors=Hirschfeld RM |title=The Comorbidity of Major Depression and Anxiety Disorders: Recognition and Management in Primary Care |journal=Primary Care Companion to the Journal of Clinical Psychiatry |volume=3 |issue=6 |pages=244–54 |date=December 2001 |pmid=15014592 |pmc=181193 |doi=10.4088/PCC.v03n0609 }}</ref> Depressed people have increased rates of alcohol and substance use, particularly dependence,<ref>{{cite journal |vauthors=Grant BF |title=Comorbidity between DSM-IV drug use disorders and major depression: results of a national survey of adults |journal=Journal of Substance Abuse |volume=7 |issue=4 |pages=481–97 |year=1995 |pmid=8838629 |doi=10.1016/0899-3289(95)90017-9 }}</ref><ref>{{cite journal | vauthors = Boden JM, Fergusson DM | title = Alcohol and depression | journal = Addiction | volume = 106 | issue = 5 | pages = 906–14 | date = May 2011 | pmid = 21382111 | doi = 10.1111/j.1360-0443.2010.03351.x | hdl = 10523/10319 | hdl-access = free }}</ref> and around a third of individuals diagnosed with [[attention deficit hyperactivity disorder]] (ADHD) develop comorbid depression.<ref>{{cite book |title=Delivered from distraction: Getting the most out of life with Attention Deficit Disorder |url=https://archive.org/details/deliveredfromdis00edwa |url-access=registration |vauthors=Hallowell EM, Ratey JJ |year=2005 |publisher=Ballantine Books |location=New York|isbn=978-0-345-44231-4 |pages=[https://archive.org/details/deliveredfromdis00edwa/page/253 253–55]}}</ref> [[Post-traumatic stress disorder]] and depression often co-occur.<ref name=NIMHPub/> Depression may also coexist with ADHD, complicating the diagnosis and treatment of both.<ref>{{cite journal |vauthors=Brunsvold GL, Oepen G |title=Comorbid Depression in ADHD: Children and Adolescents |journal=Psychiatric Times |volume=25 |issue=10 |year=2008 |url=http://www.psychiatrictimes.com/adhd/article/10168/1286863 |url-status=live |archive-url=https://web.archive.org/web/20090524050341/http://www.psychiatrictimes.com/adhd/article/10168/1286863 |archive-date=24 May 2009 }}</ref> Depression is also frequently comorbid with [[alcohol use disorder]] and [[personality disorder]]s.<ref>{{cite journal |vauthors=Melartin TK, Rytsälä HJ, Leskelä US, Lestelä-Mielonen PS, Sokero TP, Isometsä ET |title=Current comorbidity of psychiatric disorders among DSM-IV major depressive disorder patients in psychiatric care in the Vantaa Depression Study |journal=The Journal of Clinical Psychiatry |volume=63 |issue=2 |pages=126–34 |date=February 2002 |pmid=11874213 |doi=10.4088/jcp.v63n0207 }}</ref> Depression can also be exacerbated during particular months (usually winter) in those with [[seasonal affective disorder]]. While [[Digital media use and mental health|overuse of digital media]] has been associated with depressive symptoms, using digital media may also improve mood in some situations.<ref>{{cite journal | vauthors = Hoge E, Bickham D, Cantor J | title = Digital Media, Anxiety, and Depression in Children | journal = Pediatrics | volume = 140 | issue = Suppl 2 | pages = S76–S80 | date = November 2017 | pmid = 29093037 | doi = 10.1542/peds.2016-1758G | doi-access = free }}</ref><ref>{{cite journal | vauthors = Elhai JD, Dvorak RD, Levine JC, Hall BJ | title = Problematic smartphone use: A conceptual overview and systematic review of relations with anxiety and depression psychopathology | journal = Journal of Affective Disorders | volume = 207 | pages = 251–259 | date = January 2017 | pmid = 27736736 | doi = 10.1016/j.jad.2016.08.030 | s2cid = 205642153 }}</ref>

Depression and [[pain]] often co-occur. One or more pain symptoms are present in 65% of people who have depression, and anywhere from 5 to 85% of people who are experiencing pain will also have depression, depending on the setting—a lower prevalence in general practice, and higher in specialty clinics. Depression is often underrecognized, and therefore undertreated, in patients presenting with pain.<ref>{{cite journal |vauthors=Bair MJ, Robinson RL, Katon W, Kroenke K |title=Depression and pain comorbidity: a literature review |journal=Archives of Internal Medicine |volume=163 |issue=20 |pages=2433–45 |date=November 2003 |pmid=14609780 |doi=10.1001/archinte.163.20.2433 |url=http://archinte.ama-assn.org/cgi/content/full/163/20/2433(fulltext) |doi-access=free }}</ref> Depression often coexists with physical disorders common among the elderly, such as [[stroke]], other [[cardiovascular diseases]],<ref>{{Cite journal |last1=Krittanawong |first1=Chayakrit |last2=Maitra |first2=Neil Sagar |last3=Qadeer |first3=Yusuf Kamran |last4=Wang |first4=Zhen |last5=Fogg |first5=Sonya |last6=Storch |first6=Eric A. |last7=Celano |first7=Christopher M. |last8=Huffman |first8=Jeff C. |last9=Jha |first9=Manish |last10=Charney |first10=Dennis S. |last11=Lavie |first11=Carl J. |date=1 September 2023 |title=Association of Depression and Cardiovascular Disease |url=https://linkinghub.elsevier.com/retrieve/pii/S0002934323003340 |journal=The American Journal of Medicine |language=English |volume=136 |issue=9 |pages=881–895 |doi=10.1016/j.amjmed.2023.04.036 |issn=0002-9343 |pmid=37247751}}</ref> [[Parkinson's disease]], and [[chronic obstructive pulmonary disease]].<ref>{{cite journal|vauthors=Yohannes AM, Baldwin RC|title=Medical Comorbidities in Late-Life Depression|journal=Psychiatric Times|volume=25|issue=14|year=2008|url=http://www.psychiatrictimes.com/depression/article/10168/1358135|access-date=10 June 2009|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614095605/https://www.psychiatrictimes.com/10168/1358135}}</ref>