Red cell distribution width and depressive symptoms: A failed replication in female adolescents.

Objectives: Despite the increasingly high prevalence and serious consequences of depression in adolescents, there is a lack of economical and reliable biomarkers to aid the diagnostic process. Recent findings suggest that red blood cell distribution width (RDW) is an easily obtainable biomarker of depression in adults. Here, we aimed to replicate the finding of increased RDW in clinically depressed adolescents.

Methods: Data from depressed adolescent female patients (n = 93) and healthy controls (HC) (n = 43) aged 12-17 years from the AtR!Sk-bio cohort study were retrospectively analysed. We compared RDW between groups and tested whether there was an association between RDW and depression severity and global (psychiatric) symptom severity. We also examined the influence of age on RDW.

Results: There was no significant difference between depressed patients and healthy controls and no association between RDW and depression severity. However, higher RDW values were associated with greater global symptom severity. Regardless of group, there was a positive association between RDW and age.

Conclusions: RDW appears to be unfit as an aid for clinical diagnosis of depression in adolescents, but may be useful in assessing global psychiatric symptom burden.