Effect of metabolic abnormalities on efficacy of Probiotics for depression

Probiotics are currently adjunctive for depression; their efficacy may vary with comorbid obesity or liver steatosis, needing tailored research.

This study aimed to evaluate the effectiveness of probiotics in alleviating symptoms of depression, anxiety, and stress among patients diagnosed with depressive disorders, stratified based on the presence of obesity or comorbid metabolic syndrome. Additionally, it sought to explore whether specific lifestyle, clinical, or laboratory factors could envisage the probiotics' efficacy in the treatment of depression.

This parallel-group, prospective, randomized, double-blind, controlled study included 116 individuals diagnosed with depression. They were assigned to either receive a probiotic supplement with Lactobacillus helveticus and Bifidobacterium longum, or a placebo, for 60 days. Psychometric evaluations were directed at 5 intervals during the trial. 

Blood pressure, waist circumference, full blood count, C-reactive protein, lipid profile, fasting blood sugar and body weight were recorded before the use of the probiotic supplement.

The use of probiotics did not show noteworthy advantages over the placebo in terms of overall depression scores. However, patients supplemented with probiotics exhibited a higher occurrence of attaining minimum clinically important differences compared to those in the placebo group (74.5% versus 53.5%; X2(1, n = 94) = 4.53; p = 0.03; NNT = 4.03), both in the general population and among those receiving anti-depressants. Greater severity of pre-intervention metabolic abnormalities was associated with lowered improvements in psychometric test scores. Conversely, higher baseline stress levels were linked to more significant improvements.

The progression of metabolic conditions like overweight, excessive adipose tissue, and liver steatosis, appears to correspond with reduced improvements in psychometric parameters on self-assessment scales.