Based on our preclinical data showing a potential accelerating effect of acetylsalicylic acid (ASA) in combination with fluoxetine in an animal model of depression, we examined the effect of ASA augmentation therapy on selective reuptake inhibitors (SSRI) in major depressed non-responder patients. Twenty-four non-responder patients having received at least 4 weeks of an adequate SSRI treatment were included in a pilot open-label study. Participants were treated openly during 4 weeks with 160 mg/day ASA in addition to their current antidepressant treatment. The combination SSRI-ASA was associated with a response rate of 52.4%. Remission was achieved in 43% of the total sample and 82% of the responder sample. In the responder group, a significant improvement was observed within week 1 (mean Hamilton Depression Rating Scale-21 items at day 0=29.3+/-4.5, at day 7=14.0+/-4.1; P<0.0001) and remained sustained until day 28. Despite limitations due to the open nature of this study, our preliminary results confirm our preclinical findings and are in favour of an accelerating effect of ASA in combination with SSRIs in the treatment of major depression. Potential physiological and biochemical mechanisms may involve an anti-inflammatory and/or neurotrophic effect.

Evidence has accumulated suggesting that major depression is associated with dysfunction of inflammatory mediators. Moreover, antidepressants show an anti-inflammatory action possibly related to their clinical efficacy. An improvement in psychiatric symptoms has been recently reported in patients treated with anti-inflammatory drugs for other indications. These data imply that inflammation may be involved in the pathogenesis of depression and that anti-inflammatory drugs may be used as an adjunctive therapy. The aim of the present study was to evaluate the behavioural effect of the co-administration of acetylsalicylic acid (ASA, 45 mg/kg or 22.5 mg/kg) and fluoxetine (FLX, 5 mg/kg) in the chronic escape deficit model of depression. The chronic escape deficit model is based on the modified reactivity of rats to external stimuli induced by exposure to unavoidable stress and allows evaluation of the capacity of a treatment to revert the condition of escape deficit. In this model, FLX alone needs to be administered for at least 3 weeks to revert this condition. Our results show that combined treatment of fluoxetine and ASA completely reverted the condition of escape deficit by as early as 7 days, the effect being already partially present after 4 days. The effect was maintained after 14 and 21 days of treatment. ASA alone was ineffective at any time tested and the effect of fluoxetine was significant only at 21 days. These results, together with clinical data from preliminary results, suggest that ASA might accelerate the onset of action of selective serotonin reuptake inhibitor antidepressants.