Scientific knowledge increased with the development of the classification system designed to diagnose specific mental disorders, and researchers found other ways to classify and characterize psychoneurotic conditions. Thus, in DSM-III, anxiety disorders included phobic disorders, anxiety states, and post-traumatic stress disorders (PTSD). However, DSM-5 introduced some changes in the grouping of anxiety disorders.
The changes were related to the neurobiological, genetic, and psychological features common for the disorders. Thus, anxiety disorders were subdivided into anxiety, OCD, and trauma- and stressor-related disorders. For the first time, scientists took into account the role of brain functions in developing stress, panic, and other mental illnesses. In addition, they grouped disorders based on their developmental connections. All these changes demonstrated the development of scientific knowledge about psychoneurotic conditions.
Although the changes were aimed to broaden the classification of anxiety disorders, the real reason underlying these changes is the need to improve the clinical usefulness and reliability of the manual. Science is constantly changing, and the knowledge about psychiatric disorders increases. Constant updates advance the validity of the manual and help ensure the stability and correctness of the diagnostic data on time.
Moreover, the biggest change in DSM-5 was removing the multi-axial system. In previous editions, five axes were used to assess and organize biopsychosocial information, while in DSM-5, the first three axes were combined into one. Such improvements were made to decrease the artificial differences between diagnoses and accelerate the process of making a diagnosis and administering treatment. In addition, pharmaceutical impact on medical diagnosis is another reason for changes. To avoid medicalizing sadness or grief, more precise classifications have been created. All these changes were aimed to make diagnoses more accurate and respond to psychiatric research more quickly.