Oxidative stress has been implicated in the pathophysiology of depression and anxiety disorders and may be influenced by antidepressant use.

This study investigated the association of oxidative stress, measured by plasma levels of F2-isoprostanes and 8-hydroxy-2′-deoxyguanosine (8-OHdG), reflecting oxidative lipid and DNA damage respectively, with major depressive disorder (MDD), generalized anxiety disorder, social phobia, panic disorder, agoraphobia and antidepressant use in a large cohort.

Data was derived from the Netherlands Study of Depression and Anxiety including patients with current (n = 1641) or remitted (n = 610) MDD and/or anxiety disorder(s) (of which n = 709 antidepressant users) and 633 controls. Diagnoses were established with the Composite Interview Diagnostic Instrument. Plasma 8-OHdG and F2-isoprostanes were measured using UHPLC-MS/MS. ANCOVA was performed adjusting for sampling, sociodemographic, health and lifestyle variables.

F2-isoprostanes did not differ between controls and patients, or by antidepressant use. Patients (current or remitted) using antidepressants had lower 8-OHdG (adjusted mean 38.3 pmol/L) compared to patients (current or remitted) without antidepressants (44.7 pmol/L) and controls (44.9 pmol/L, P < 0.001; Cohen's d 0.26). Findings for 8-OHdG were similar over all disorders and all antidepressant types (SSRIs, TCAs, SNRIs; P < 0.001).

Contrary to previous findings this large-scale study did not find increased oxidative stress measured by F2-isoprostanes or 8-OHdG in MDD or anxiety disorders. 8-OHdG levels were lower in antidepressant users, which suggests antidepressants may have antioxidant properties.

The authors have not supplied their declaration of competing interest.