Psychopharmacology and conditional reflexes

Drugs may be used in several ways to investigate their role in behavior. (1) The placebo effect is usually connected with the relation of the person to the drug. (2) Using the drug as an unconditional stimulus, its action may help to analyze the role of peripheral vs. central stimuli in the formation of conditional reflexes; our work has shown that the effect of drugs which act solely at the peripheral nerve endings without the involvement of the central nervous system cannot become conditioned. (3) The action of drugs on the conditional reflex (CR) compared with their action on the unconditional reflex (UR) explains some of their behavioral effects. (4) Schizokinesis is often prominent in the action of drugs. Although a drug may increase the level of the heart rate, for example, it can, on the other hand, diminish the reactivity shown in the CR. Meprobamate and mescaline affect differently the cardiac and the motor components of the CR, illustrating a schizokinesis. (5) The type of individual is an important factor in the action of drugs; the same drug may have opposite effects on different individuals. This leads to the conclusion that a drug should fit the individual as well as the disease. (6) Autokinesis is often seen in drug action. Therefore a single dose of some drugs, such as acetylcholine, epinephrine or LSD, may permanently change the relationships between excitation and inhibition, in the direction of improvement or deterioration (positive or negative autokinesis).