Pharmaco(Epi)Genetic, Proteomic, and Microbiomic Study of Obsessive-Compulsive

The purpose of this study is to determine the effects of (epi)genetic variants on the response to SSRIs in obsessive-compulsive disorder (OCD) subject.

The investigators will recruit drug-naive or drug-free(> 3 months) OCD subjects (n=200). The participants will get SSRIs for their OCD symptoms. The type and dose of SSRIs will not be restricted and will depend on the individual participant's state. However, the investigators will be recommended to follow usual clinical guideline (the Korean treatment algorithm for OCD, 2004). At baseline, 4 month, 6 months, and 1 year after treatment, the participants will be evaluated by Yale-Brown Obsessive-Compulsive Scale(YBOCS), Montgomery Asberg Depression Rating Scale(MADRS), Dimensional Obsessive-Compulsive Scale(DOCS), Toronto alexithymia scale (TAS), interpersonal reactivity index (IRI), Barratt impulsiveness scale (BIS), and the Measure of Constructs Underlying Perfectionism(M-CUP), Beck Depression Inventory(BDI), Beck Anxiety Inventory(BAI), Intolerance of Uncertainty (IOU), Metacognition, Disgust scale, Early Trauma Inventory (ETI). And a part of participants will be taken resting state functional MRI.

The research participants will donate approximately 10-15 ml of blood, from which we will extract DNA and separate serum. Using various (epi)genetic analyses, proteomics, and microbiome analysis (circulating bacterial extracellular vesicles) methods, we will analyze the association of various (epi)genetic variants, protein profiles, microbiome and the anti-obsessive-compulsive responses.