Association of pro-inflammatory cytokines with severity of various psychiatric disorders is shown. Evidence suggests omega-3 fatty acids reduce psychiatric symptoms due to anti-inflammatory properties.

To evaluate if serum levels of pro-inflammatory cytokines correlate with the intensity of PTSD symptoms, and the observed change in symptoms’ severity induced by omega-3 supplementation.

We included 26 Croatian Homeland war veterans (aged 39–60) with chronic PTSD and no major comorbidity, who were on stable therapeutic sertraline dose at least three months before recruitment. Levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) were determined by the enzyme-linked immunosorbent assay method. Intensity of PTSD symptomatology was assessed by Clinician-Administered PTSD Scale (CAPS), Hamilton Anxiety Scale (HAM-A) and 17-item Hamilton Depression Scale (17-HAM-D). During 12 weeks, participants took omega-3 capsules (600 mg/day) while continuing sertraline therapy.

Most participants presented with moderate PTSD evaluated by CAPS. At baseline, cytokine levels were not associated with the severity of PTSD symptoms, as measured by all three scales (P ≥ 0.209). After 12 weeks of omega-3 supplementation the severity of PTSD symptoms significantly decreased, on average by 8 to 13% on the psychometric scales per person (P < 0.001 for all). However, no association was found between the change in cytokine levels and the change in scores, induced by omega-3, on the assessed scales (P ≥ 0.730).

Cytokine levels are not associated with PTSD severity or with improvement in PTSD symptomatology. At the same time, sertraline therapy supplemented with omega-3 seemed to reduce the severity of PTSD symptoms.

The authors have not supplied their declaration of competing interest.