Age

18–65

Sex

ALL

Healthy volunteers

Not accepted

Meets DSM-5 criteria for a single episode or recurrent episode;
HAM-D-17 ≥ 22, total score of HAM-D-17 items 4, 5, and 6 ≥ 3;
MADRS ≥ 20, CGI-S ≥ 4;
Absence of antidepressant medication use or discontinuation of antidepressant medication prior to screening.

Treatment-resistant depression;
Suicide attempt or suicide behavior within the past 6 months;
Used antibiotics within the past 2 weeks;
Currently use insomnia medication, excluding non-benzodiazepine drugs taken consistently for 4 weeks;
With medical history or surgical history that may affect probiotic colonization.

Probiotic IBNI617 for Moderate to Severe Depression