Objective: The overall aim of this thesis was to investigate the remission criteria according to the Remisson in Schizophrenia Working Group (RWSG), mainly from a longitudinal perspective.

Paper I showed that all remission symptoms in the RSWG criteria, affected the remission status in the cross-sectional setting. In the longitudinal setting, the symptoms Delusions and Hallucinatory behavior contributed mostly to the fluctuation between remission and non-remission, while negative symptoms were more prominent in the group that never reached remission. Finally, the sustainability of remission was significantly longer when only minimal symptom intensity occurred, compared with mild.

Paper II showed that the cognitive areas associated with long-term remission pattern were executive functioning, working memory and verbal functioning, where significant better results were shown in the group of stable remission with only minimal symptoms compared to the group never reaching remission. Verbal functioning was the only cognitive area that could predict long-term remission pattern, as a better result increased the probability of being in long-term remission.

Paper III focused on the patient’s perspective and examined the relationship between subjective quality of life (SQoL) and remission. The paper showed significant associations between a better SQoL, self-assessed with Short Form Health Survey-36, and both cross-sectional remission and long-term. A significant better SQoL was present regardless of being in stable remission over time or if remission was reached during the study period.

Conclusions: The thesis support that the RSWG criteria for remission is a valuable concept, also from a longitudinal perspective. Taken together, the results emphasize the heterogeneity of schizophrenia, where different groups within the disorder show different clinical characteristics. This thesis highlights the importance of regular assessments of broad clinical status, to support a higher frequency and sustainability of remission.

I denna avhandling granskas remissionskriterierna enligt Remission Schizophrenia Working Group (RSWG) för personer med schizofreni ur ett longitudinellt perspektiv.

Studie I visade att alla inkluderade symtom i RSWG-kriterierna bidrog till att avgöra remissionsstatus. Negativa symtom bidrog mest till förekomsten av icke-remission över tid, medan växlingen mellan remission och icke-remission varierade mer med positiva symtom. En ökad hållbarhet i remission förelåg vid en minimal symtomintensitet, jämfört med en mild. 

Studie II visade att patienterna i stabil remission hade bättre kognitiv funktion, jämfört med de som aldrig var i remission. Ju bättre verbal funktion desto högre sannolikhet förelåg dessutom att tillhöra gruppen i stabil remission över tid. 

Studie III visade att den subjektiva livskvaliteten (SQoL) var bättre vid remission jämfört med icke-remission. En bättre SQoL förelåg oavsett om remissionsförekomsten över tid var stabil eller om den uppnåddes under studieperioden, både för den mentala och fysiska hälsan. 

Avhandlingen stöder remissionskriteriernas användbarhet ur ett longitudinellt perspektiv, och återspeglar sjukdomens heterogenitet. Avhandlingen poängterar vikten av att systematiskt följa upp de i avhandlingen undersökta faktorerna för att öka förekomsten samt hållbarheten i symtomatisk remission.