Structural and functional markers of language signify the symptomatic effect of depression: A systematic literature review

Human behaviour is encoded and decoded through language. The latter acts as a marker in conceptualising the symptomatic effect of depression and stress. Based on this premise, this study reviewed the results and findings of both qualitative and quantitative research literature on the discourse of depressive patients and which was published between 2010 to 2020. A total of 80 research articles were examined and evaluated for interpretation using the Framework of Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA). Out of these, 25 articles were finalised for analysis and synthesis. The findings on linguistic indicators correlating to depression were interpreted based on (i) prevalent linguistic markers, (ii) the research design, (iii) the significance of the context, and (iv) the limitations of findings across studies that foil establishing the generalizability of linguistic markers. Although function and content words (first-person singular pronouns, negative emotional words) as markers are strongly associated with cognitive symptoms (self-focused attention) of depression, results across studies vary. It is observed that depressive individuals also used the third-person singular (he, she) and plural pronouns (they) while accusing others of referring to negative affect. These findings contribute to the literature on mental health by establishing a correlation between linguistic features and psychological symptoms of depression.