Effects of chlorpromazine on appetitive and aversive components of a multiple schedule.

Scientists gave dogs a two-part daily task. In one part, pressing a lever earned food. In the other part, pressing delayed a mild shock.

After the dogs learned both parts, the team injected low, medium, or high doses of chlorpromazine before each session. They counted lever presses in every part to see if the drug hit avoidance harder than food seeking.

Small doses slightly raised food-lever presses and left avoidance alone. Bigger doses lowered both kinds of presses about the same.

The drug did not pick on avoidance behavior; it just slowed all responding once the dose climbed.

Reberg et al. (1979) later tested adults with intellectual disability in a residential home. They stopped the same drug, then started it again in an ABAB design. Some people improved off the drug, others did not. Their human data extend the 1962 dog study by showing that real-world withdrawal effects are personal and mixed.

Rutter et al. (1987) used the same two-part schedule but swapped chlorpromazine for a benzodiazepine. The new drug raised timeout-seeking presses while leaving avoidance presses almost untouched. This contrast underlines that different drugs target different parts of a schedule, so you cannot predict one drug from another.

McKearney (1976) showed that d-amphetamine and pentobarbital flip their effects on punished behavior depending on whether food or shock-termination keeps the response going. Together these papers warn: the contingency, not just the drug, decides what you will see.

If a client on antipsychotic medication shows slower work or lower compliance, do not assume the drug is calming "bad" behavior while sparing "good" skills. High doses may flatten all operant rates. Track each response class separately during med changes, and share data with the prescribing doctor so doses can be adjusted or shifted to drugs with more selective effects.