According to the literature, patients with chronic pain and mental disorders constitute a huge, heterogeneous group. However, it is known that social and psychological processes closely affect the level and expression of chronic pain. In this paper, we present a review of the literature, define methods of identifying pain biomarkers and consider the possibility of using them to assess pain in mental disorders. Group researchers searched PubMed, Scope, and Cochrane databases for "pain biomarkers in mental disorders" between 2011 and 2021. for available databases for full-text, peer-reviewed studies and review publications using the following keywords: pain biomarkers, neuroimaging pain, pain metabolomics, pain and psychiatric disorders, pain electroencephalography (EEG), serum pain biomarkers, saliva biomarkers, and diagnosis pain. The search included full-text articles, clinical trials, randomized controlled trials, and systematic reviews. Was used part of the PRISMA method to review the literature systematically. A literature search identified 283 studies based on the initially set inclusion and exclusion criteria. In the subsequent selection stages, 11 studies were selected for analysis. There are three main areas of the possible use of biomarkers for the clinical assessment of pain in psychiatric patients, neuroimaging, changes in metabolite levels in body fluids, and changes in gene expression. As a result of the review, individual pain mediators were distinguished that may be markers of pain in psychiatric patients. Some mediators indicate the specificity of pain and are of diagnostic importance. However, despite significant advances in research, most of the described biomarkers found in clinical trials assessing the severity and frequency of pain have no practical significance in psychiatric disorders. It is possible to diagnose pain based on neuroimaging using various methods, genetic methods, body fluids: blood and urine. Of the many, body fluid biomarkers are the most advanced. Discussion: Biomarker research is a dynamically developing field. The review has proposed new ways to diagnose pain by identifying pain biomarkers. Work presented pain diagnostics in psychiatric disorders based on biomarkers from various neuroimaging methods, blood and urine analysis. The possibility of new, effective techniques gives hope for the correct diagnosis of pain, especially in patients with mental disorders, which would allow for appropriate and adequate therapeutic therapies. In clinical practice is limited to a few methods. Assessment of pain biomarkers in body fluids (serum, saliva, and urine) seems to be the most practical and promising method of clinical application. Conclusions: There are new techniques that give hope for the correct diagnosis of pain, especially in patients with mental disorders, which will allow for their proper and adequate therapy. According to the literature, patients with chronic pain and mental disorders constitute a huge, heterogeneous group. However, it is known that social and psychological processes closely affect the level and expression of chronic pain.