© 2019, International League of Associations for Rheumatology (ILAR).Objective: Psoriatic Arthritis Impact of Disease 12-item questionnaire (PsAID-12) has been developed to be used in psoriatic arthritis in daily practice. The aim of the present study was to assess the change values of PsAID-12 in PsA patients continuing or discontinuing anti-TNF treatment. Methods: We recruited patients from the Hacettepe University biological database (HUR-BIO). Overall, 70 PsA patients had PsAID-12 score before the initiation of the first anti-TNF treatment. Stopping or switching the anti-TNF treatment due to inefficacy was definitely considered a negative response. Changes were evaluated by the comparison with the baseline PsAID-12 score in compliance with the favorable and unfavorable responses to anti-TNF treatments. The standardized response mean (SRM) was used for determining the response. Results: Seventy (78.6% female) patients were analyzed and their mean age was 45.5 years (12.0 years). The mean follow-up duration was 18.3 months (12.6 months). At baseline, the mean PsAID-12 score was 6.6 (1.5). Physicians stopped or switched the treatment in 28 patients (40.0%) due to the inefficacy of anti-TNF treatment. The ΔPsAID-12 score was 0.25 (1.71) in the patients discontinuing anti-TNF treatment and 3.52 (2.31) in the patients continuing their anti-TNF treatment (p < 0.001). The SRM scores higher for PsAID-12, particularly in the well response to anti-TNF treatments. Conclusion: A decrease of 3.5 units in PsAID-12 score shows a favorable response to anti-TNF treatment. Changes in PsAID-12 score had well discrimination capacity for anti-TNF treatments.