The development of treatment outcome measures has followed a pattern in which treatments are first developed to affect symptoms, and measures are developed concomitantly to detect differences in response rates between the treatment group and a comparison placebo group. For example, in the 1950s, distinct pharmacologic therapies were developed to lower blood pressure and to lessen the hallucinations and delusions associated with schizophrenia. At the same time, measures to assess these latter outcomes were validated.