Abstract
The present article focused on the problem of validity, reliability and specificity of psychiatric diagnoses.The authors moved by the concept of syndrome, defined by Sydenham in the 18th century as a constellation of several interrelated symptoms, showing a stable, characteristic structure and a peculiar prognosis, in order to analyse the peculiarity of the current psychiatric nosology. In our opinion, the current nosographic system based on DSM-IV criteria, prevents psychiatry from benefiting of the significant technological progress that has led the rest of medical sciences to important clinical achievements in the last 20 years. The case of Generalized Anxiety Disorder was taken as an example of a disease characterized by unstable diagnostic criteria, high rate of comorbidity and uncertain boundaries. An analysis of the data from the Sesto Fiorentino study was performed to investigate the presence of common mood and anxiety symptoms across the most represented DSM IV diagnoses, in order to evaluate the specificity of these symptoms.The results supported the hypothesis of a low specificity of these symptoms, suggesting the need for psychiatry to find new and more specific markers and instruments.