Figure 1.

Flow diagram describing the systematic review process.

Notes: **Publication type included abstracts or conference proceedings with insufficient details, book chapters, editorials/letters without new data, or protocol papers. Study design describes reviews with no original data, case reports, animal studies, or fundamental science papers. Study population describes studies with no neurodegenerative disease group. Study outcome describes studies with no psychiatric outcome, no inflammatory measure, or no testing for association between psychiatric and inflammatory measures. This flow diagram is based on PRISMA reporting guidelines.¹⁶²