Measurement of psychological distress and well-being.

Psychological distress and well-being are important aspects of quality of life measurements in psychosomatic medicine. The concept of improvement in medicine refers to a clinical distance along which the current state of the patient is compared to the pretreatment position. Quality of life covers, however, more than one distance or dimension in this respect; e.g. well-being, side effects of treatment, and psychosocial stressors. The psychometric aspects of these dimensions are analysed with reference to nomothetic and idiographic methods. The nomothetic approach is the selection of the most unbiased scale tailored to the disorder under investigation. The idiographic approach is the construction of a hermeneutical or meaningful scale for the individual patient. For both methods the clinical improvement index is the most appropriate statistic.