Psychiatric rating scales validity

Owing to the lack of well-defined, broadly established and valid biological markers in psychiatric diseases, the clinical assessment of patients is routinely based on different rating scales. When selecting a scale for use in the investigation of the effect of a drug on a particular disorder, some potential sources of error should be kept in mind ... 

Psychiatric Scale (IMPS) is used to measure psychotic syndromes in hospitalized adults capable of being interviewed. The 89 items are rated on the basis of a psychiatric interview. This test has been well validated and requires 10 to 15 minutes following a 35- to 45-minute interview. There are ten scores excitement, hostile belligerence, paranoid projection, grandiose expansiveness, perceptual distortions, anxious intropunitiveness, retardation and apathy, disorientation, motor disturbances, and conceptual disorganization. 

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