We considered the association of each attribute with treatment response using interestingness measures and found important attributes that associated with treatment response. Results Results showed that low obsession and compulsion severities, family history of mental illness, illness duration less than 5 years, being married, and female were the most associated variables with responsiveness to fluvoxamine pharmacotherapy. his/her illness duration was less than 5 years, he/she responded to 12-week fluvoxamine pharmacotherapy with the probability of 91%. We also found useful and applicable rules for resistant and refractory patients. Conclusion This is the first study where association rule mining approach was used to extract predicting rules for treatment response in OCD. Application of this method in personalized medicine may help clinicians in taking the right therapeutic decision. criteria for OCD were recruited from Imam Hossein hospital (Tehran, Iran) between 2014 and 2017. OCD diagnosis was established by a psychiatrist, and its subtypes and severity were investigated by an expert psychologist through the structured interview using Yale-Brown Obsessive Compulsive Scale (Y-BOCS) checklist and severity scale.32 The sociodemographic data were collected through a questionnaire consisting of the patients full name, address, age at assessment, the age of onset, gender, marital status, educational level, occupation, chief complaint, illness duration, history of material usage, and the family history of psychiatric Borneol disorders, specifically OCD. Participants were in the age range of 18C65 years, having OCD symptoms for more than 1 year and with total Y-BOCS severity score more than 9 (suggested cutoff point for Iranian Borneol patients33); a total of 17 patients out of 151 had total Y-BOCS scores 9C16. The exclusion criteria were having a history of psychotic disorders or intellectual disability; reporting severe neurological Borneol pathology; history of substance usage; diagnosis with other Axis l disorders except for depression, stress, or tic disorder; and under other pharmacotherapy or cognitive behavioral therapy (CBT). Pharmacotherapy was defined as a 12-week treatment with fluvoxamine (150C300 Borneol mg), which has been described previously.28 Briefly, the escalating fluvoxamine daily dose was initiated from 25 mg/day and increased up to 100 mg/day in the third CDK4 week. Fluvoxamine daily dose for the next 3 weeks was 150 mg/day, and after the sixth week, patients were visited by the psychiatrist and received maximum tolerated dose of the fluvoxamine for the next 6 weeks. No concomitant therapy was allowed during the whole treatment period, either pharmacological or non-pharmacological. Y-BOCS severity was evaluated at the beginning of the treatment period and after 12 weeks, and based on the reduction in patients Y-BOCS score, the patients were divided into two groups: group A (responders) included patients who showed 35% reduction in Y-BOCS scores after treatment with fluvoxamine, and group B (non-responders) was composed of patients who exhibited 35% reduction in Y-BOCS scores.34 We included another group (refractory patients) consisting of patients who experienced various selective serotonin reuptake inhibitor (SSRI) trials at maximum tolerated dose during their illness period but did not respond to them adequately.34 From 330 OCD patients initially included in the study, 151 persons completed their pharmacotherapy. Others were excluded because of refusal to come for follow-up (N=108), not taking medication properly (N=38), discontinuity in pharmacotherapy due to complications, including allergy to the drug (N=8), meeting exclusion criteria during pharmacotherapy (N=6), and other reasons (N=19). Since we used the previously published data set to investigate the association rule data mining approach, the CONSORT diagram which summarizes the flow of participants through different stages of the trial was presented previously.28 The excluded and included patients showed no significant differences in mean baseline scores considering their demographic (sex and marital status) and clinical characteristics (history of psychiatric disorders, age at assessment, age of onset, obsession severity, compulsion severity, and total severity) as well as symptom dimensions from the Y-BOCS symptom checklist (data not shown, all occurs, then also happens with a certain probability.19 Usually, an overwhelming number of rules are created in association rule mining, and evaluating this amount of rules by a user is tedious and time-consuming. Interestingness measures are beneficial and play an essential role in the detection of strong and interesting rules from the set of discovered rules. These indexes are intended for selecting and ranking rules according to their potential interest to the user. Confidence and support are two traditional measures of rule interestingness.