The effects of any drug treatment on cognitive function are typically studied in groups of subjects. Observations made about the behavior of the drug, in the study sample, are then generalized to the population from which the sample was drawn. However, the magnitude and pharmacodynamic qualities of the response to many central nervous system-active drugs are known to vary in the population. Therefore, it is useful to consider statistical models for the detection of cognitive change in response to a drug treatment in individual subjects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46374/1/213_2006_Article_331.pd