The diagnosis of depression: current and emerging methods

Depression is one of the leading causes of disability in adolescents and adults, particularly starting from age 15 years and older. Diagnosis of depression has traditionally been made based on clinical criteria, including patient current symptoms and history. This process is widely used but relies on subjective interpretation. To standardize both the data obtained and data interpretation, various interview-based instruments and noninterview methods exist for screening and testing for depression in various clinical settings. This article evaluates the technical basis for and clinical performance of these various instruments and methods to diagnosis depression in clinical settings. Traditional tools include physician-administered or patient self-administered interview tools that have reasonable clinical accuracy depending on the threshold score and may lead to a full diagnostic evaluation for high-risk patients. In addition, older laboratory methods such as the dexamethasone test have contributed to the diagnosis of depression over a long period. Newer diagnostic methods such as genomics, proteomics, and metabolomics are technically sophisticated and objective and are beginning to emerge in psychiatry. Although promising, further evaluation of these methods is needed to fully demonstrate their clinical value and accuracy.