Therapists have to deal with verbal systems and often work with verbal exchange. Therefore, a psychological theory is required, which teaches the therapist how to accomplish this task. The BRT is a theory of human language and cognition that explains how people use their verbal behavior as stimuli in their interrelations and how they act and react, based on the resulting relationships. This behavior is learned very early in the course of language acquisition and functions as a generalized operant. A prerequisite for this is the ability of people to undergo mental simulation. This enables them to construct diverse relational frameworks between individual stimuli. Without relational frameworks, people cannot function. The ability to establish a relational framework is a prerequisite for the formation of rule-governed behavior. Rule-governed behavior economizes complex decision processes, creates interpersonal security and enables dealing with events before they take place. On the other hand, the same properties that enable people to solve problems effectively can also contribute to rigid adherence to rules and experience avoidance. Relational frameworks, once established, outweigh other sources of behavioral regulation. Thus, it can become the basis of psychopathology. Poor contextual control makes it difficult for people to devote flexible, focused and voluntary attention to the present and align their actions with the immediate present. Contextual psychotherapy methods that are based on the BRT start precisely at this point: Targeted establishment of new contingencies in the therapeutic interaction through systematic strengthening of metacognitive mode and through the establishment of new rules that make possible a change in the rule-governed behavior enable undermining of dysfunctional rule-governed behavior and build up desirable behavior. This allows any therapeutic process to be more effective--regardless of the patient's expressed symptoms.