The Subjective Units of Distress Scale (SUDS; also known as Subjective Units of Disturbance Scale) is a measurement tool used by clinicians and healthcare professionals to determine the level of subjective distress a sufferer is experiencing.
Subjective distress is the discomfort, pain, and general uncomfortable feelings a person is experiencing.
Subjective means that it comes from the perspective of the individual experiencing it. SUDS is a numbered scale (1-10, 1-100) that measures the level at which an experience is disturbing or distressing to an individual.
For example, a SUDS could be used on a patient who is suffering from anxiety. They are asked to choose which number best represents the level at which they are experiencing the anxiety symptoms ranging from 0 (no anxiety, totally relaxed) to 10 (highest anxiety ever felt, extremely disturbed and disrupted by the symptoms). SUDS are commonly used by clinicians to measure the effectiveness of treatment.
So, for example. the anxiety patient mentioned before chose a score of 9 when initially evaluated by the clinician. After treatment with psychotherapy and short-term medication the patient is asked again and responds that they are at a 4. This shows a marked improvement and that the treatment has been effective.