Sesongvariasjon i stemningslidelser: En kunnskapsoversikt

The study explored the literature concerning seasonal variations in mood disorders. The purpose was to give a summary of the included studies in this systematic review, evaluate their research design and in relation to effect estimates discuss the validity of assumptions within the field. The PRISMA framework was used in the selection of the 34 studies pertaining to seasonal variations in mood disorders. There is great heterogeneity in regards to research design, samples and outcome measures applied in the different studies. The disparity between the designs of the different studies is also reflected in their results. When the different trends reported in the data material were compared there was no evidence for a strong indication of one clear trend, for example a higher occurrence of depression during winter. The studies included in this review indicate that the research field of seasonal variations in mood disorders is fragmented.