Medication nonadherence decreases the success of clinical treatment and the efficient use of resources, thereby creating a barrier to effective health care. In this report, we describe the achievement of treatment collaboration through motivational interviews (MI) in a patient with treatment-resistant schizophrenia. In this case study, we conducted six MIs during which we asked open-ended and reflective questions, established empathy with the patient, and developed discrepancies, leading to ambivalent feelings being revealed. We used the importance, confidence and self-efficacy ruler. The MI method can be used to ensure continued treatment effectiveness, to increase patient awareness about the disease and benefits of treatment, and to increase patients' self-efficacy.