The prevalence rates of childhood depression vary somewhat, depending on the sample and period assessed.
In the US, data from the 2016 National Survey of Children’s Health suggests that 3.2% of children aged 3 to 17 years have a current diagnosis of depression.[3]Ghandour RM, Sherman LJ, Vladutiu CJ, et al. Prevalence and treatment of depression, anxiety, and conduct problems in US children. J Pediatr. 2019 Mar;206:256-67.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6673640
http://www.ncbi.nlm.nih.gov/pubmed/30322701?tool=bestpractice.com
In adolescents, the 12-month prevalence rises to approximately 8%.[4]Avenevoli S, Swendsen J, He JP, et al. Major depression in the national comorbidity survey-adolescent supplement: prevalence, correlates, and treatment. J Am Acad Child Adolesc Psychiatry. 2015 Jan;54(1):37-44.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408277
http://www.ncbi.nlm.nih.gov/pubmed/25524788?tool=bestpractice.com
Before puberty, girls and boys have similar rates of depression, but a gender difference emerges around early adolescence from the age of 12 onwards, when the diagnosis becomes more common in girls.[4]Avenevoli S, Swendsen J, He JP, et al. Major depression in the national comorbidity survey-adolescent supplement: prevalence, correlates, and treatment. J Am Acad Child Adolesc Psychiatry. 2015 Jan;54(1):37-44.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408277
http://www.ncbi.nlm.nih.gov/pubmed/25524788?tool=bestpractice.com
Depression becomes more than twice as prevalent in young women than in men by mid-adolescence to early adulthood (aged 14-25 years).[4]Avenevoli S, Swendsen J, He JP, et al. Major depression in the national comorbidity survey-adolescent supplement: prevalence, correlates, and treatment. J Am Acad Child Adolesc Psychiatry. 2015 Jan;54(1):37-44.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408277
http://www.ncbi.nlm.nih.gov/pubmed/25524788?tool=bestpractice.com
[5]Albert PR. Why is depression more prevalent in women? J Psychiatry Neurosci. 2015 Jul;40(4):219-21.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4478054
http://www.ncbi.nlm.nih.gov/pubmed/26107348?tool=bestpractice.com
The ages of 13 to 18 represent a key period for depression onset in both boys and girls; depression rates rise substantially for both sexes during this time.[3]Ghandour RM, Sherman LJ, Vladutiu CJ, et al. Prevalence and treatment of depression, anxiety, and conduct problems in US children. J Pediatr. 2019 Mar;206:256-67.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6673640
http://www.ncbi.nlm.nih.gov/pubmed/30322701?tool=bestpractice.com
[6]Hankin BL, Young JF, Abela JR, et al. Depression from childhood into late adolescence: influence of gender, development, genetic susceptibility, and peer stress. J Abnorm Psychol. 2015 Nov;124(4):803-16.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4662048
http://www.ncbi.nlm.nih.gov/pubmed/26595469?tool=bestpractice.com
The majority of depressive illnesses in adults can be traced back to their origins in adolescence.[7]Kessler RC, Berglund P, Demler O, et al. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry. 2005 Jun;62(6):593-602.
https://jamanetwork.com/journals/jamapsychiatry/fullarticle/208678
http://www.ncbi.nlm.nih.gov/pubmed/15939837?tool=bestpractice.com
There is some evidence to suggest an increase of major depressive disorder in certain areas within the past two decades; in Australia, a national survey found an approximately 50% increase in community prevalence rates between 1998 and 2014.[8]Lawrence D, Hafekost J, Johnson SE, et al. Key findings from the second Australian child and adolescent survey of mental health and wellbeing. Aust N Z J Psychiatry. 2016 Sep;50(9):876-86.
https://api.research-repository.uwa.edu.au/ws/portalfiles/portal/8930412/Lawrence_ANZJP_KeyResults_Version2.pdf
http://www.ncbi.nlm.nih.gov/pubmed/26644606?tool=bestpractice.com
In the UK, the number of 12- to 17-year-olds prescribed antidepressants more than doubled between 2005 and 2017 (although antidepressant prescriptions decreased slightly overall for children aged 5-11 between 1999 and 2017).[9]Jack RH, Hollis C, Coupland C, et al. Incidence and prevalence of primary care antidepressant prescribing in children and young people in England, 1998-2017: a population-based cohort study. PLoS Med. 2020 Jul 22;17(7):e1003215.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7375537
http://www.ncbi.nlm.nih.gov/pubmed/32697803?tool=bestpractice.com
It is unclear to what extent this represents a change in depression rates, or difference in diagnosis and treatment, during this period.
The presence of poverty has been associated with an increased risk of children requiring treatment for depression.[3]Ghandour RM, Sherman LJ, Vladutiu CJ, et al. Prevalence and treatment of depression, anxiety, and conduct problems in US children. J Pediatr. 2019 Mar;206:256-67.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6673640
http://www.ncbi.nlm.nih.gov/pubmed/30322701?tool=bestpractice.com
[9]Jack RH, Hollis C, Coupland C, et al. Incidence and prevalence of primary care antidepressant prescribing in children and young people in England, 1998-2017: a population-based cohort study. PLoS Med. 2020 Jul 22;17(7):e1003215.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7375537
http://www.ncbi.nlm.nih.gov/pubmed/32697803?tool=bestpractice.com
[10]Wijlaars LP, Nazareth I, Petersen I. Trends in depression and antidepressant prescribing in children and adolescents: a cohort study in The Health Improvement Network (THIN). PLoS One. 2012;7(3):e33181.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3302807
http://www.ncbi.nlm.nih.gov/pubmed/22427983?tool=bestpractice.com
Depressive disorders may be higher in indigenous children and in children with chronic medical illness.[11]Pumariega AJ, Roth EM, Rogers KM. Depression in immigrant and minority children and youth. In: Rey JM, Birmaher B, eds. Treating child and adolescent depression. Baltimore, MD: Lippincott Williams & Wilkins; 2009:321-31.[12]Pinquart M, Shen Y. Depressive symptoms in children and adolescents with chronic physical illness: an updated meta-analysis. J Pediatr Psychol. 2011 May;36(4):375-84.
http://jpepsy.oxfordjournals.org/content/36/4/375.long
http://www.ncbi.nlm.nih.gov/pubmed/21088072?tool=bestpractice.com
Depression in childhood is frequently associated with psychiatric and behavioural comorbidities. In the US, around 73.8% of children aged 3 to 17 years with depression also have anxiety, and 47.2% have co-occurring behavioural problems.[3]Ghandour RM, Sherman LJ, Vladutiu CJ, et al. Prevalence and treatment of depression, anxiety, and conduct problems in US children. J Pediatr. 2019 Mar;206:256-67.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6673640
http://www.ncbi.nlm.nih.gov/pubmed/30322701?tool=bestpractice.com