Placebo attribution in methadone patients

The effect of external cues on the attributed effectiveness of a placebo was evaluated with methadone patients and a nonaddict control group. Two sources of external feedback, implicit dosage strength (liquid drug color) and explicit performance information (pursuit rotor feedback), were varied along with drug usage. The results indicated that the methadone patients made significantly greater placebo attributions and relied more upon the external cues in making those attributions than did the nonaddict control group. Implications for drug therapy are presented.