Psychiatric diagnosis is a complex and difficult issue. Ontological and epistemological questions permeate the nosological literature, with innumerable considerations about the uncertain ontological status of psychiatric disorders and the difficulties in providing irreproachable definitions for them. These considerations help to place the issue of nosology into proper context and to appreciate its subtleties and difficulties. Nosological classification is necessary and can be useful despite some inherent flaws and limitations. The current nosology, however, relies on a categorical approach that has been much criticised. The prototype approach, which does not rely on strict operational criteria, has both strong points and potential disadvantages. The dimensional approach represents an alternative that has received empirical support while having its share of difficulties.In the 1990s, we developed an instrument called the SVARAD (the Italian acronym for "Scala per la VAlutazione RApida Dimensionale", i.e. "rapid dimensional assessment scale") that covers ten psychopathological dimensions, selected based on clinical relevance and consistent identification in factor analytic studies. It is an observer-rated scale that consists of ten items (Apprehension/Fear, Sadness/Demoralisation, Anger/Aggressiveness, Obsessiveness, Apathy, Impulsivity, Reality Distortion, Thought Disorganisation, Somatic Preoccupation/Somatisation, and Activation), each scored on a 5-point scale. To enhance ease of use, the scoring instructions are included directly in the scale, rather than being provided in a separate manual. Two decades of clinical and research experience have corroborated the reliability, validity, and acceptability of the SVARAD. It is particularly suitable for clinical and research settings where a reliable, comprehensive, and yet rapid assessment of psychopathology is needed.