Prospective Associations Between Personality Traits and Major Depressive Disorder Symptom Severity: The Mediating Role of Illness Representations.

Major depressive disorder (MDD) patients' personality traits and illness representations are linked to MDD severity. However, the associations between personality and illness representations in MDD and the mediating role of illness representations between personality and MDD severity have not been investigated. This study aimed to prospectively investigate the aforementioned associations and the possible mediating role of illness representations between personality and MDD severity. One hundred twenty-five patients with a MDD diagnosis, aged 48.18 ± 13.92 (84% females), participated in the study. Personality traits were measured with the Traits Personality Questionnaire at baseline. Illness representations were measured with the Illness Perception Questionnaire-Mental Health about five months later (mean = 5.08 ± 1.14 months). MDD severity was measured about 10 months after the baseline assessment (mean = 9.53 ± 2.36 months) with the Beck Depression Inventory. SPSS 29 and AMOS 27 were used to conduct correlational and parallel mediation analyses. According to the results, Neuroticism was positively and Extraversion was negatively linked to MDD severity. Negative MDD impact representations fully mediated these associations. Neuroticism and Extraversion are linked to future MDD severity through patients' representations of MDD's impact. Restructuring maladaptive representations about MDD's impact can be a promising way to reduce symptom severity in patients with high Neuroticism and low Extraversion levels.