Therefore, it is necessary to account for the acquisition of habits. Due to certain limitations of the behaviorism approach, there have been revisions to the theory over the century. For example, although behaviorism helped people to forecast, alter, and change behavior over time, it did not attempt nor intend to understand how or why the theory worked. The present-day social cognitive approach asserts that behavior is results from an ongoing reciprocal three-way relationship among the individual (cognition), the environment (physical context, which consists of the organizational structure and design, social context or other people), and the person's past behavior. This broader view, called cognitive behavioral therapy (CBT) incorporates the cognitive in addition to the behavioral approaches to therapy and view people "as active seekers and interpreters of information, not just responders to environmental influences" (Nevid, 2007, p. 484). Many psychologists now believe that behavior is understood best by studying the reciprocal relationships between individuals and their environment.

Psychopathology is directly the result of inappropriate learning either from a classical or operant conditioning model (Fall, Holden & Marquis, 2004). The behavioral or learning theory of anxiety argues that anxiety is a conditioned response to a specific environmental stimulus. In a model of classic conditioning, a wife married to an abusive husband, for example, may become anxious whenever she sees him. Through generalization, she begins to distrust all men. Similarly, in the social learning model, a boy may develop an anxiety response by imitating the anxiety of someone else in his environment, such as an anxious parent.

The therapy in such cases consists of relearning, with the focus on the present, not the past. At times the past may be discussed briefly to gain a foundation, as may the future to establish goals, but the main thrust is on the present. The therapy is helpful since the clients learn to use fundamental behavioral principles in their lives (Fall, Holden & Marquis, 2004).

The existential theory, also from the early 20th century, developed from a reaction to the dehumanization of the 1800s and beginning of the 1900s, when society emphasized the compartmentalization of family, work and religion, in order to cope with the strictly stratified world where humans were treated as cogs in machines. This compartmentalization resulted in a loss of self-awareness and self-estrangement. The basis of this existentialism was derived from the writings of Kierkegaard, Nietzche, Heidegger and Sartre. Freud's psychoanalysis reflected a deterministic viewpoint of humans acting similar to automatons, but unlike this psychoanalytic approach where theory and treatment were of primary importance, existential psychotherapists placed philosophical considerations as the focus for both theory and treatment.

Existential theory of anxiety provides models for generalized anxiety, in which no specifically identifiable stimulus exists for a chronically anxious feeling. The central concept is that people experience feelings of living in a purposeless universe. Anxiety is their response to the perceived void in existence and meaning. Such existential concerns have become exacerbated since the development of nuclear weapons and, more recently, bioterrorism. A major distinction between the mechanistic approaches of Freud and the behaviorists and the existentialists is ontology or the study of being. This ontological approach emphasizes the spectrum of existence and the ever-changing balance between being and nonbeing that occurs within individuals in their environment (Perez-Alvarez & Sass, 2008).

Similar to psychoanalysts, the existentialists think of the human psyche as a range from total unconsciousness or being completely unaware to total consciousness or being aware. Relatively unconscious psychic material either never emerged into the larger realm of consciousness or emerged and was lost through repression. A result of consciousness is the creation of a primary self or transcendental ego that distinguishes one's self from the rest of the world (May & Yalom, 2000). In existentialism, these two structures -- the level of consciousness and self -- are all that are...

Each of the needs and wishes that a person has in his/her existence come in direct conflict with what are called the givens of life, or conditions that are present in each moment that may threaten existence. Every person has the innate ability to perceive these threats and to generate anxiety. Yalom defines these givens as death, freedom, isolation and meaningless (Martz, 2002).
Another existential factor is called Dasein or "being there." This is when each person at every moment of existence has a manner of being with a level of fullness. Dasein includes the awareness of life's givens and the degree to which threat is perceived and whether they generate physical or psychological anxiety (Perez-Alvarez & Sass, 2008). People will respond differently to this anxiety based on personal defense mechanisms. Similar to psychoanalysts, the existentialists believe that every individual unconsciously does use strategies to ignore or alter reality to keep him/herself safe from being overwhelmed by anxiety. However, above the psychoanalytic defenses, the existentialists add specialness or when a person believes he/she has immunity from the givens and in the existence of an ultimate rescuer who can be appeased in exchange for being completely protected. The right amount of defenses can ward away anxiety and preserve existence, but excessive defenses can ignore or amplify anxiety and hinder fulfillment.

The therapeutic approach in existentialism can be alternatively gentle and confrontive as the therapist and client attempt to form a meaningful and real relationship. The therapy helps because, within the context of this relationship, the client can start to face the reality of the givens.

Models and theories of psychopathology, as noted here of psychoanalytic, behavioral and existential and their associated therapies, are not indicative of different scientific fact where one is "right" and the other "wrong" in methodology. It is rather the extent of variation in perspective that occurs within the field of psychopathology itself. Several favored models are more popular within any society at any time period, and also change historically over time and from one society to another in influence. Each of these three models has provided help to scores of individuals over the decades who are suffering from anxiety as well as other psychological problems. Although they continue to undergo change, they also continue to play a major role in the health and well-being of their clients.