Opsesivno-kompulzivni poremećaj spada u skupinu anksioznih poremećaja, a karakteriziran je pojavom opsesivnih misli i kompulzivnih radnji. Prvi simptomi ovog poremećaja najčešće se javljaju u dobi od 9 do 13 godina. U Međunarodnoj klasifikaciji bolesti (MKB -10) nalazi pod oznakom F.42. MKB-10 dijeli OKP na tri oblika: oblik s prevladavajućim opsesijama, oblik s prevladavajućim kompulzijama i mješoviti oblik, koji je ujedno i najčešći. Opsesije ili obuzetosti objašnjavamo kao ponavljajuće i perzistentne misli, doživljaje ili osjećanje koje osoba doživljava kao intruzivne i neprimjerene, a uzrokuju anksioznost ili nelagodu. Kompulzije ili prisile su pak ponavljane radnje ili ponašanje koje osoba smatra nužnima izvršiti kao odgovor na opsesiju te koje služe smanjenju anksioznosti. Sadržaj opsesija i kompulzija mijenja se s dobi djeteta, opsesivna zabrinutost oko redoslijeda i simetrije javlja se kod 2/3 predškolske djece, u osnovnoškolskoj dobi prevladavaju opsesivne misli i kompulzivne radnje vezane za školu. Adolescenti kao najčešću opsesiju navode strah od trovanja i misli o ozljeđivanju sebe ili nekih poznatih osoba, a najčešće kompulzije su rituali vezani za pranje, čišćenje, provjeravanje i uređivanje. OKP se prema težini kliničke slike može podijeliti na tri oblika: lakši, srednji i teški. Brojne su teorije o etiologiji OKP-a, u biološkoj teoriji spominju se poremećaji u količini pojedinih neurotransmitera, strukture, elektrofiziološke i neuroendokrine promjene te u novije vrijeme neuroimunološka teorija koja povezuje OKP s infekcijom beta-hemolitičkim streptokokom u djetinjstvu, kao i psihološke i sociološke. Različiti su načini liječenja OKP-a, farmakoterapijski, psihoterapijski, kao i drugi. Istraživanja pokazuju vrlo dobre rezultate korištenja samo kognitivno – bihevioralne terapije, iako se u praksi nerijetko koristi kombinacija psihoterapije i lijekova. Tijek bolesti je kroničan, a oporavak može biti dug i spor ovisno o težini bolesti i odgovoru na terapiju. Obsessive-compulsive disorder belongs to the group of anxiety disorders, and is characterized by the appearance of obsessive thoughts and compulsive actions. The first symptoms of this disorder most often occur between the ages of 9 and 13. In the International Classification of Diseases (ICD -10), it is under the designation F.42. ICD-10 divides the OCD into three forms: a form with the prevailing obsessions, the form with the prevailing compulsions and the mixed form, which is also the most common. Obsessions or obsessions are explained as repetitive and persistent thoughts, experiences or feelings that a person perceives as intrusive and inappropriate, and cause anxiety or discomfort. Compulsions or compulsions are repeated actions or behaviors that a person deems necessary to perform in response to obsession and that serve to reduce anxiety. The content of obsessions and compulsions changes with the age of the child, obsessive concerns about order and symmetry occur in 2/3 of preschool children, in primary school age obsessive thoughts and compulsive actions related to school prevail. Adolescents cite the fear of poisoning and thoughts of harming themselves or some celebrities as the most common obsession, and the most common compulsions are rituals related to washing, cleaning, checking and editing. According to the severity of the clinical picture, OCD can be divided into three forms: lighter, medium and heavy. There are numerous theories about the etiology of OCD, biological theory mentions disorders in the amount of individual neurotransmitters, structure, electrophysiological and neuroendocrine changes, and more recently neuroimmunological theory that connects OCD with infection with beta – hemolytic streptococcus infection in childhood, as well as psychological and sociological. There are different ways of treating OCD, pharmacotherapeutic, psychotherapeutic. Research shows very good results of using only cognitive – behavioral therapy, although in practice a combination of psychotherapy and medication is often used. The course of the disease is chronic, and recovery can be long and slow depending on the severity of the disease and the response to therapy.