Functional Analytic Psychotherapy
Functional Analytic Psychotherapy (FAP) is an approach to clinical psychotherapy that uses a Radical Behaviorist position informed by B.F. Skinner's analysis of Verbal Behavior.
Although sufficient for use alone, this approach is offered as something that may be practiced in addition to Cognitive Behavioral Therapy (CBT). FAP focuses on in-session client-therapist interactions as the basis for clinical change.
Clinically relevant behavior (CRB) represents the categories of client change in FAP and there are three general categories of CRBs. CRB1 represents problematic behavior that occurs in-session that is the focus of change. CRB2s are the behaviors that manage or deal with CRB1s. CRB3s represent client statements or rules about positive changes that are encouraged in FAP. The concept of CRB3s might be seen as being akin to Cognitive Behavioral Therapy (CBT). However, despite these similarities, the interpretation and theoretical justification for them are different .

# Basic conceptual structure
The basic FAP analysis utilizes what is called the clinically relevant behavior (CRB1), which is the client's presenting problem as presented in-session. Client in-session actions that improve their CRB1s are referred to as CRB2s. Client statements, or verbal behavior, about CRBs are referred to as CRB3s. The CRB3s, although based on Skinner's analysis of Verbal Behavior, are what most closely approximate CBT cognitions . In session focus on client behavior approximates the psychoanalytic conception of the therapeutic alliance (which is psychoanalytic parlance contains transference and counter-transference issues).
FAP also explores covert verbal behavior such as mands-to-self and tacts-to-self, as well as rule governed versus contingency shaped behavior. 
As a treatment Functional Analytic Psychotherapy places great focus on the therapeutic relationship. The result is a highly emotional and relationally based therapy. Often people do not associate such relationally focused interventions with a Skinnerian treatment.

# Applications
The treatment manuals for functional analytic psychotherapy are published online for those who desire to do research 
Functional analytic psychotherapy has been applied to many complex clinical problems such as relational behavior around complex trauma (see  ). In the area of trauma the concept is that the relationship is where the post traumatic stress was formed and thus the relationship is where it needs to be improved. The relational work of FAP has also been applied to the supervision relationship

## Research support
The major component of functional analytic psychotherapy is to target particular clinically relevant behavior and the use in session natural reinforcement to increase appropriate relational behavior. This approach has received considerable research over the past 50 years and can be considered an empirically valid process. (see ). In some respects empirically supported principles, like those supporting FAP are more important then empirical support for treatment packages 

# History
Functional Analytic Psychotherapy was created by Dr. Robert Kohlenberg and Dr. Mavis Tsai in 1991.. Functional analytic therapy offers an interesting model of child development and personality development (see child development for more]]
As such it represents an extension of Stephen Hayes attempt to incorporate Behaviorism with clinical issues (although Hayes' approach utilized his own Relational Frame Theory instead of Skinner's analysis of Verbal Behavior).

# Depression
Jonathan Kanter explored the use of Functional Analytic Psychotherapy and another modality in one article for use with depression, a common clinical problem.
Kantor also explored FAP in conjunction with CBT for depression in 2006.

# Third Generation Behavior Therapy
Often Functional Analytic Psychotherapy is lumped with Behavioral Activation, Dialectical Behavior Therapy, Integrative Behavioral Couples Therapy, and Acceptance and Commitment Therapy. Together these therapies are often referred to as third generation behavior therapy because the focus less on cognitive phenomena and more on functional analysis commonly found in applied behavior analysis and a behavioral theory of language and cognition.