{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T02:34:08Z","timestamp":1789439648417,"version":"build-2803163510"},"reference-count":0,"publisher":"Cambridge University Press (CUP)","issue":"7","license":[{"start":{"date-parts":[[2004,10,21]],"date-time":"2004-10-21T00:00:00Z","timestamp":1098316800000},"content-version":"unspecified","delay-in-days":20,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Psychol. Med."],"published-print":{"date-parts":[[2004,10]]},"abstract":"<jats:p><jats:bold>Background.<\/jats:bold> Based on prevalence studies and the few incidence studies of pervasive developmental disorders (PDDs) the prevalence and incidence of these disorders have been claimed to be increasing.<\/jats:p><jats:p><jats:bold>Method.<\/jats:bold> The annual and age-specific prevalence and incidence rates of childhood autism, atypical autism, Asperger's disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS) in Denmark during the period 1971\u20132000 in children younger than 10 years were estimated using data from the Danish Psychiatric Central Register.<\/jats:p><jats:p><jats:bold>Results.<\/jats:bold> A total of 2\u00b74 million children younger than 10 years were followed and 2061 cases with the PDDs studied were identified. Generally, the prevalence and incidence rates of the PDDs studied were stable until the early 1990s after which an increase in the occurrence of all disorders was seen, until 2000. The annual incidence rate per 10000 children younger than 10 years was 2\u00b70 for childhood autism, 0\u00b77 for atypical autism, 1\u00b74 for Asperger's disorder, and 3\u00b70 for PDD-NOS in 2000. We calculated a \u2018corrected\u2019 prevalence of childhood autism at 11\u00b78, atypical autism at 3\u00b73, Asperger's disorder at 4\u00b77, and PDD-NOS at 14\u00b76 per 10000 children younger than 10 years on 1 January 1 2001.<\/jats:p><jats:p><jats:bold>Conclusions.<\/jats:bold> We found that the estimated prevalences of the PDDs studied were probably underestimated. Furthermore, the increasing prevalence and incidence rates during the 1990s may well be explained by changes in the registration procedures and more awareness of the disorders, although a true increase in the incidence cannot be ruled out.<\/jats:p>","DOI":"10.1017\/s0033291704002387","type":"journal-article","created":{"date-parts":[[2004,10,21]],"date-time":"2004-10-21T09:06:05Z","timestamp":1098349565000},"page":"1339-1346","source":"Crossref","is-referenced-by-count":66,"title":["The incidence and prevalence of pervasive developmental disorders: a Danish population-based study"],"prefix":"10.1017","volume":"34","author":[{"given":"M. B.","family":"LAURITSEN","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C. B.","family":"PEDERSEN","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P. B.","family":"MORTENSEN","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"56","published-online":{"date-parts":[[2004,10,21]]},"container-title":["Psychological Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0033291704002387","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,5,6]],"date-time":"2019-05-06T16:08:58Z","timestamp":1557158938000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0033291704002387\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,10]]},"references-count":0,"journal-issue":{"issue":"7","published-print":{"date-parts":[[2004,10]]}},"alternative-id":["S0033291704002387"],"URL":"https:\/\/doi.org\/10.1017\/s0033291704002387","relation":{},"ISSN":["0033-2917","1469-8978"],"issn-type":[{"value":"0033-2917","type":"print"},{"value":"1469-8978","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,10]]}}}