This report focuses on the application of different proteomic techniques in diagnosis and treatment of psychiatric disorders such as major depression, suicidal behavior, schizophrenia, and attention deficit/hyperactivity disorder (ADHD). Firstly, we briefly describe different analytic approaches that can be applied for the discovery of specific biomarkers for diagnosing the above disorders, as well as for monitoring the effect of their treatment. Secondly, we discussed the types of biomarkers in general used in biomedicine for characterizing different disorders and diseases. Next, the potential applications of these biomarkers for diagnosing and managing major depression, suicidal behavior, schizophrenia, and ADHD are discussed in details. Forensic aspects of these biomarkers for the above disorders are also considered. Finally, we discuss the potential of specific biomarkers for distinguishing between comorbid psychiatric disorders in clinical setup as well as their potential for understanding mechanisms underlying the disorders and in discovery of new treatment strategies.