This study aimed to investigate the independent correlation of the severity of fatigue in female patients with Major Depressive Disorder (MDD) with age at illness onset.

We studied 70 female patients (34 inpatients), aged 23-65 years (mean 48.2±10.6 years), with MDD as assessed with the M.I.N.I. version 5.0.0. All patients were currently in a Major Depressive Episode, with a 17-item Hamilton Depression Rating Scale (HDRS) score ≥17, and free of major fatigue-associated conditions. Reported fatigue was assessed with the 14-item Fatigue Questionnaire (FQ). Pearson's (r) or Spearman's (rho) correlations between FQ, age, inpatient status, HDRS and age at onset were calculated. A multiple regression analysis was then performed, with FQ as the dependent variable.

The FQ score was significantly correlated with HDRS (r=0.406, p< 0.001) and age at onset (r=-0.281, p=0.02). In the multiple regression model, HDRS and age at onset turned out as significant independent predictors of the FQ score, with standardised beta coefficients of 0.419 (p< 0.001) and -0.3 (p=0.006), respectively (R2=0.255).

The severity of fatigue in female patients with major depression is independently correlated with earlier age at illness onset.