Abstract
Olfactory dysfunction (OD) has been reported in individuals who recovered from COVID-19. Those with OD after COVID-19 (COVID-19 group) exhibited more severe psychiatric symptoms than those with OD from other etiologies (non-COVID-19 group). This study investigates differences in psychological symptoms and related clinical factors between these groups. Fifty-two participants (COVID-19 group: 26; non-COVID-19 group: 26) were recruited. Both objective and subjective olfactory function were assessed, and symptoms of depression, anxiety, and perceived stress were measured using self-reported scales. There were no significant differences in objective and subjective olfactory function or psychological symptoms between the groups, except for age and the short version of the Questionnaire of Olfactory Disorders-negative statements (sQOD-NS). The sQOD-NS score was negatively correlated with OD duration only in the COVID-19 group. In both groups, the sQOD-NS was significantly correlated with Patient Health Questionnaire-9 (PHQ-9) scores. Mediation analysis showed that OD duration indirectly affected PHQ-9 scores via the sQOD-NS in the entire sample, particularly in the COVID-19 group. These findings suggest that subjective distress from OD may mediate the relationship between OD duration and depressive symptoms in COVID-19 patients, highlighting the need for targeted psychiatric interventions after recovery from COVID-19.