Evaluation of the arachidonic acid pathway in bipolar disorder: a systematic review

Bipolar disorder (BD) is a mood psychiatric disorder described by changes between depressive, hypomanic, or manic episodes. The aimed of the present study was evaluated possible changes in the AA pathway in BD through a systematic review of observational studies. A search in the electronic databases was proceeded, on Cochrane Library, MEDLINE, EMBASE, PsycINFO, Google Scholar and the British Library for studies published until August 2020. A search strategy was developed using the terms: "Bipolar Disorder" and "Phospholipase A2" or "Arachidonic Acids" or "Cyclooxygenase 2" or "Prostaglandins E" as text words and Medical Subject Headings (i.e., MeSH and EMTREE). Seven primary studies were included in the systematic review, with a total of 246 BD patients, 20 depression patients, and 425 heathy controls (HC). The studies showed contradictory results in the AA and PLA2, no primary articles with COX and PGE2 assessments were included in this review. According to the Newcastle-Ottawa quality score scale (NOS), our systematic review presented high quality. The investigation of the inflammatory pathway of AA still needs further investigation and evidence, given the growing number of studies suggesting the efficacy of anti-inflammatory drugs as adjunctive therapy in the pharmacological treatment of BD.