Background: In January 2019, the official launch of new guidelines within specialist mental health services and substance abuse treatment in Norway took place, with treatment organized according to structured patient pathways. The pathway system introduced maximum lengths for assessment, treatment, and evaluation and the coding of the different steps. The system was based on overall goals to improve services by focusing on user participation, coordinated patient flow, avoidance of unnecessary waiting time, more equal services independent of geographic location, and greater emphasis on somatic health and lifestyle. The purpose of our study was to examine the implementation of patient pathways within mental health services, and more specifically how trust emerges and influences the final outcome. Methods: Our study included four outpatient clinics for adults in four community health centres in different parts of Norway. The informants consisted of treatment personnel, leaders, and pathway coordinators, and data were collected through qualitative group and individual interviews. Results: The results indicated four distinct themes or reactions towards the patient pathway system. These themes were unclarity regarding the overall goals and content of the patient pathway; increased coding, registration and administrative work, which professionals experienced as stressors; an IT and journal system that did not correspond with the coding of the patient pathway; and an unrealistic distinction between assessment and treatment. All of the above encouraged health professionals to reduce the importance of patient pathways, as well as increase their resistance towards health authorities. Conclusions: To understand how and why health professionals made sense of the patient pathway, theory on trust can be used to show how professionals within health care interpret the implementation of patient pathways as a desire to control more areas and work practices within mental health care, leading to their distrust towards the new system Trial registration: Not neccessary