IL1B and bipolar disorder: The main finding of the present study is that antidepressant chronotherapeutic treatment with combined TSD+LT decreases the IL-1β:IL-1ra ratio in patients with bipolar depression, the decrease being proportional to the baseline IL-1β:IL-1ra ratio, and to the clinical efficacy of the TSD cycle: patients with higher baseline levels showed the higher decrease in IL-1β:IL-1ra, which associated with clinical response, while patients with lower baseline values showed negligible changes in the IL-1β:IL-1ra, and responded to treatment independent of them.