Few well-controlled studies have considered neurofeedback treatment in adult psychiatric patients. In this regard, the present study investigates the characteristics and effects of neurofeedback on adult psychiatric patients in a naturalistic setting. A total of 77 adult patients with psychiatric disorders participated in this study. Demographic data and neurofeedback states were retrospectively analyzed, and the effects of neurofeedback were evaluated using clinical global impression (CGI) and subjective self-rating scales. Depressive disorders were the most common psychiatric disorders (19; 24.7 %), followed by anxiety disorders (18; 23.4 %). A total of 69 patients (89.6 %) took medicine, and the average frequency of neurofeedback was 17.39 ± 16.64. Neurofeedback was applied to a total of 39 patients (50.6 %) more than 10 times, and 48 patients (62.3 %) received both β/SMR and α/θ training. The discontinuation rate was 33.8 % (26 patients). There was significant difference between pretreatment and posttreatment CGI scores (<.001), and the self-rating scale also showed significant differences in depressive symptoms, anxiety, and inattention (<.001). This is a naturalistic study in a clinical setting, and has several limitations, including the absence of a control group and a heterogenous sample. Despite these limitations, the study demonstrates the potential of neurofeedback as an effective complimentary treatment for adult patients with psychiatric disorders.