AbstractWhen contrasting drugs (i.e., chlordiazepoxide versus pentylenetetrazol) are examined in drug‐drug, drug‐saline, or drug 1‐drug 2‐saline tasks, one can begin to assess whether such drugs represent orthogonal cues or reflect an underlying cue dimension. Both adaptation level theory and opponent‐process theory are applied to the analysis of drug discriminative performance. Three indices that can differentiate between orthogonal and opponent affective states utilizing drug‐drug discrimination tasks are discussed in relation to these two theories, and a model to characterize further the similarity between pharmacologically and environmentally induced anxiety