Insomnia and exacerbation of anxiety associated with high-EPA fish oil supplements after successful treatment of depression

A 54-year-old male consulted his general practitioner for increasing general anxiety and mild panic attacks despite effective treatment for recurrent major depressive disorder, which included a fish oil supplement enriched in eicosapentaenoic acid (EPA). The patient would awaken suddenly at night with shortness of breath and overwhelming worry. During the daytime, he felt a general, nonspecific anxiety and frequently experienced sympathetic activation upon confronting routine challenges. He also experienced dyspnea-induced feelings of panic. He reported that he stopped taking the fish oil supplements after several more months of symptoms, and his anxiety and insomnia then largely disappeared. Several weeks later, he resumed consumption of high-EPA fish oil at the prior dosage for 2 days. On both nights, the patient reported nighttime awakening similar to the previous episodes, followed by daytime agitation. Since halting the fish oil supplements, the anxiety and insomnia have not returned and his depression remains in remission.