The type of treatment that most psychiatric disturbances receive at present is a mixture of pharmacotherapy and psychotherapy, following the principle that mental functions are the result of the activities of brain machinery subsequent to the interaction between individuals and their external environment. We now know the molecular mechanism of action of several psychoactive drugs but have scant understanding of the correlation between molecular events and mental function. As for psychotherapy, we know that it may have beneficial effects on patients' behavior but ignore the issue of whether this has any correlate at molecular level. A black box still exists between drugs, neurotransmitters, receptors, and the higher brain functions defined as anxiety, emotion, arousal, etc. Yet mental treatments imply a therapeutic method in which the blend of drugs and words administered to patients is determined by the choice of the therapist and by the specific pathology recognized through clinical diagnosis. In this epistemologically confused situation, the pharmaceutical industry is playing a major role in orientating the medical profession towards the use of more and more powerful neurotropic substances with very detailed molecular actions and plenty of side-effects. Nevertheless, the use of psychotropic drugs has allowed the opening of the psychiatric hospitals and the 'liberation' of millions of psychiatric patients. This beneficial effect is counterbalanced by the dependency of millions of individuals on psychotropic drugs. The situation leads to a number of questions relative to the possible links among words, molecules, and behaviors. The present paper illustrates a theoretical model which can be used to compare and contrast psychotherapy and pharmacotherapy.