The functional interview aims to identify behavioral contingencies characteristic of socially anxious behavioral episodes and their relationship to the DSM-5 diagnostic criteria for SAD (APA, 2022). These behavioral contingencies are present in the five functional criteria for recognizing SAD (Iêgo & Ribeiro, 2024) and are described in Table 1.

To standardize the nomenclature of the technical terms used in this work, it was considered that: (a) a behavioral episode is the functional unit of behavior (Matos, 1999), that is, the smallest fragment of organism-environment interaction necessary for understanding the function of behavior in a given interaction. It may be a triple contingency, a complex contingency, or a contingency with chained responses; (b) a behavioral contingency is the structure that presents relationships between the responses that constitute the behavior under analysis and the environmental events that affect it and/or are affected by it. An operant behavioral contingency corresponds to “the conditions under which a consequence is produced by a response, that is, the occurrence of the consequence depends on the occurrence of the response” (Catania, 2013, p. 434). A respondent contingency “refers to the conditions under which some stimuli are followed by others” (Catania, 2013, p. 435); (c) the contingency terms of analysis are categories that group, distinguish, and delimit events that temporally participate in a behavioral episode. The term antecedent groups events occurring prior to the emission of responses. These will be grouped under the term response. The events produced by the responses are grouped under the term consequence. Chained contingencies can contain more than three terms; (d) behavioral components (or elements) are broad functional classes of either stimuli or responses that may constitute different contingency terms. Each behavioral component is labeled with an uppercase letter and a subscript numeral (e.g. S₁). The elements present in the term antecedent are represented by the letter S, while those in the term response are labeled with the letter R, and those in the term consequence with the letter C; finally, (e) behavioral events correspond to different topographical occurrences classifiable as a behavioral element.

For example, suppose an interviewee reports that he/she usually takes a tranquilizer drug before speaking in public, hides his/her hands and holds them firmly to conceal shaking, speaks in a deep voice and in a paused manner to mask sounding muffled, and wears makeup to hide blushing. In this example, each of these behaviors aimed at preventing others from noticing nervousness are the behavioral events that constitute a broad functional response class labeled “avoiding showing symptoms of anxiety in social interactions”, which in this case is the behavioral component (element) R₂. Both the behavioral element R₂ (which includes all behaviors described in this example) and the behavioral element R₁ (a class of respondent responses related to fear and anxiety) are part of the response term of a three-term operant behavioral contingency.

The elements of behavioral contingencies present in the functional criteria for SAD investigated in the interview include: an antecedent element related to social situations involving possible scrutiny by others (S₁); two consequent elements, which are negative social evaluation (C₁) and functional impairments resulting from SAD (C₂); and four elements of social anxiety responses, namely, experiencing fear and/or anxiety in social situations (R₁), avoiding showing fear/anxiety symptoms in social situations (R₂), avoiding social situations (R₃), and escaping from social situations (R₅).

Two behavioral elements present in the functional criteria were not directly investigated in the interview, namely: the antecedent stimulus warning of avoidable social situations (S₂) and the response of temporarily enduring unavoidable social situations (R₄). Since the emission of R₃ (avoiding avoidable social situations) is only possible following the presentation of S₂, the presence of S₂ is indirectly investigated when evaluating R3. Similarly, R₄ (temporarily enduring unavoidable social situations) occurs in SAD concomitantly with response R₂ and is succeeded by response R₅ (escaping from the social situation when escape is possible). Thus, the investigation of R₄ is indirectly carried out when evaluating response R₂.

Each of the behavioral elements is investigated in a specific section of the interview. The order of presentation of the behavioral elements follows the sequence in which each behavioral response is mentioned in the DSM-5. Each investigated response is then followed by the exploration of the consequent events, and then the antecedents. The functional interview also employs terminology identical to that used by the DSM (APA, 2022).

Our investigation into each of the behavioral elements that distinguish socially anxious behavior resulted in a semi-structured interview composed of 18 questions distributed across seven sections. Each section aims to identify each of the elements representative of a socially anxious behavioral episode, namely: one antecedent element, two consequent elements, and four responses.

Section I: This section comprises three questions (#1-3) designed to identify response R₁, which pertains to conditioned reflex responses occurring in social situations. The presence of response R₁ is a necessary condition to meet all DSM-5 criteria (A-H). Question #3 was designed to exclude other clinical conditions as a differential diagnosis, addressing DSM Criteria I and J.

Section II: This section comprises three questions (#4-6) designed to identify consequence C₁, which relates to the prevention of the occurrence of aversive social stimuli. These aversive social stimuli include situations implying the potential for negative evaluation by others, humiliation, embarrassment, rejection and/or offense, as described in DSM-5 criterion B.

Section III: This section comprises two questions (#7 and 8) dedicated to identifying consequence C₂, which refers to the outcomes related to distress and impairment in social, academic, occupational, or other important areas of functioning resulting from socially anxious behaviors. Consequence C₂ is described in DSM-5 criterion G and is considered the primary condition for distinguishing between behaviors consistent with SAD and other social avoidant behaviors deemed culturally acceptable.

Section IV: Consisting of one question (#9), this section is dedicated to identifying antecedent S₁ (social situations that elicit fear and anxiety responses). The examples presented in question #1 of Section I can also be revisited. The concomitant presence of antecedent S₁ and response R₁ ensures compliance with DSM-5 criteria A and C.

Section V: This section consists of four questions (#10-13) aimed at identifying response R₃ (avoidance of social situations). This involves signaled avoidance preceded by a warning stimulus (S₂) emitted precisely to prevent the occurrence of S₁ (social situations). Questions #11-13 allow for examining characteristics of social avoidance behavioral patterns (rate, conditions, etc.), thus providing parameters for determining the severity of Social Anxiety Disorder. The presence of response R₃ ensures compliance with DSM-5 criterion D.

Section VI: Consisting of three questions (#14-16), this section is aimed at identifying response R5 (escape from social situations), encompassing both overt and covert behaviors emitted to avoid enduring social situations. In order to understand aspects related to motivation and distress tolerance, question #16 was included to investigate the presence of an alternative response to R₅, i.e., deliberately enduring a social situation. The presence of response R5 ensures compliance with DSM-5 criterion D.

Section VII: Consisting of two sets of questions (#17-18), this section was designed to identify response R₂ (responses of Escape or Avoidance to avoid showing symptoms of anxiety) when an individual finds himself/herself in social situations. The presence of response R₂ ensures compliance with DSM-5 criterion B.

Table 2 presents the organization of the FISA sections and summarizes the information detailed above.

The identification and characterization of socially anxious behavior patterns are conducted by aligning the information collected in the FISA with previously proposed functional criteria (Iêgo & Ribeiro, 2024). To achieve this, it is necessary to analyze the behavioral elements identified by the FISA and evaluate correspondence between these elements and those required for each functional criterion.

The behavioral elements required to satisfy Functional Criterion 1 are investigated in sections I and IV of the FISA. Functional Criterion 2 is investigated in sections II, IV and VII; Functional Criterion 3 in sections II to V; Functional Criterion 4 in sections I to IV, VI and VII; Functional Criterion 5 in sections II, III, IV and VI. Relationships between the FISA questions and the functional criteria they correspond to are summarized in Table 3. The behavioral patterns observed through the FISA can only be characterized as socially anxious behavior patterns if all five functional criteria are simultaneously met.

Although the primary objective of the FISA is to investigate the data necessary for identifying socially anxious behavior according to previously proposed functional criteria (Iêgo & Ribeiro, 2024), it also investigates relevant information that can be used for diagnosing SAD according to DSM-5 criteria. For each DSM-5 diagnostic criterion, there are corresponding questions in the FISA (Table 4). The DSM-5 criteria A, C, E, F, I, and J are investigated in sections I and III; criterion B is investigated in sections II and VII; and criterion D in sections IV to VI.

This study demonstrates the feasibility of designing a functional assessment instrument to evaluate behavioral phenomena described in diagnostic manuals, such as SAD. To achieve this, it was first necessary to operationalize the diagnostic criteria for SAD into behavioral contingencies to distinguish socially anxious behavior, as performed in a previous work by the present authors (Iêgo & Ribeiro, 2024). Once the behavioral elements of the contingencies distinguishing the said behavior had been identified, it was then possible to examine these in the context of a clinical interview.

Thus, the FISA materializes this proposal: a semi-structured clinical interview aimed at investigating the behavioral elements typically present in behavioral episodes characteristic of socially anxious behavior. It is an instrument that facilitates the identification of socially anxious patterns through an assessment based on the functional criteria presented in Table 1. The interview was developed from the conception that socially anxious behaviors are part of reinforcement contingencies and, therefore, it is the clinician’s responsibility to investigate these contingencies (Iêgo & Ribeiro, 2024). Hence, the FISA serves as a clinical tool aligned with the analytical-behavioral understanding of the phenomenon known as SAD.

Other mental health professionals may also benefit from using the FISA. It was designed to assist not only psychologists but also psychiatrists in recognizing patterns of socially anxious behavior, as it investigates information relevant to the confirmation of DSM-5 diagnostic criteria. It is entirely feasible to collect all necessary information for diagnosing SAD according to the DSM-5 criteria via the questions in the FISA, as shown in Table 4. The FISA instrument is based on an understanding that harmonizes both with the fundamental principles of Behavior Analysis (BA) and with the current neuropsychiatric understanding of SAD.

As a functional assessment instrument, the primary outcome measure of the FISA is the data necessary to satisfy each of the five functional criteria for socially anxious behavior. Table 3 illustrates how responses from the FISA facilitate the identification of the proposed functional criteria for recognizing socially anxious behavior (Iêgo & Ribeiro, 2024). When all five functional criteria are met simultaneously, an individual exhibits a pattern of socially anxious behavior, a condition that phenomenologically corresponds to the DSM-5 diagnosis of SAD.

Both mental health professionals, with a particular emphasis on psychiatrists, and the general public have an interest in differentiating whether a certain behavioral presentation is pathological or not (APA, 2022). While acknowledging the importance of characterization from a diagnostic standpoint, behavior analysts seek to identify functional similarities among behavioral patterns and processes that cause distress to the individual and/or their environment (Sidman, 1960).

The patterns of socially anxious behavior potentially identified by the FISA may be observable in individuals with or without SAD; however, the frequency, intensity, and duration of these behavioral responses may differ. Moreover, behavioral patterns consistent with SAD may also manifest in individuals with other clinical conditions, such as Generalized Anxiety Disorder and Avoidant Personality Disorder, as well as in persons considered shy or even extroverted. Therefore, regardless of whether all five functional criteria required to achieve a diagnosis of SAD, the FISA nonetheless remains clinically relevant as long as behavioral patterns associated with distress are identified.

Regarding the reliability and validity of the information collected by the FISA, behavior analysts have a particular preference for the use of direct behavioral observation as the gold standard for data collection. However, this does not imply a rejection of methods that utilize verbal reporting by respondents, especially since it is widely recognized that no other way exists to access covert events except through the individual’s verbal reporting (Carrara, 2008; De Rose, 1999). Bolsoni-Silva and Loureiro (2010) elaborated and validated a functional interview that is methodologically recognized and has been adopted by both behavior analysts and psychologists in general. This instrument is based on the same principles by which the FISA is presented, i.e., it does not serve as a substitute for direct behavioral assessment, but rather as an additional tool to assist clinicians and other health professionals.

However, as with any other assessment instrument (Carrara, 2008), the use of the FISA requires evaluator training. In the absence of specific training, the reliability of the data collected by the FISA is compromised. Moreover, collecting information from the interview is only the first step in establishing parameters for comparison with functional criteria. The mere occurrence of behavioral elements, even those associated with SAD, does not in itself constitute a diagnosis; there must be a specific functional relationship between the behavioral events. Thus, it is necessary to follow a sequence of steps to determine whether the behavioral pattern being evaluated corresponds to socially anxious behavior, which can only be ensured after proper training and supervision of the use of this instrument.

A potential advantage of using the FISA is that it enables the collection of information that may be relevant for developing an individualized treatment plan for individuals with SAD. The FISA guides the professional during the clinical investigation stage that precedes the behavioral intervention stage in behavior-analytic therapy. During the clinical investigation, the FISA directs the search for data necessary to conduct a contingency analysis of the behavioral episodes related to the clinical complaint, providing a significant portion of the substantiating information required to proceed with the functional assessment of the case under analysis. All these activities that comprise the clinical investigation are necessary prerequisites that form the basis for case formulation in BA, a stage in which, among other things, the problem is described in behavioral terms, and potential intervention targets can be identified.

It is important to recognize that the FISA has limitations. For example, the functional interview only investigates DSM-5 criteria and does not account for potential contingencies associated with functional classes of responding characteristic of SAD that fall outside these criteria.

The FISA also does not encompass the investigation of behavioral patterns that represent desirable behavior in social situations. In line with Goldiamond (2002), who proposed investigating not only the behavior of interest but also desirable alternative behavior, it is emphasized that these patterns are important because they guide both the clinician and client toward the path to be pursued throughout treatment. Other idiographic behavioral classes may also remain beyond the scope of FISA investigation. Therefore, the use of this interview does not negate the importance of an individualized assessment aimed at offering the client an intervention “tailored” to their idiosyncrasies.

In addition to limitations specific to the FISA, there are also limitations inherent to the use of indirect investigative instruments (Alonso & Moscoso, 2017), such as the possibility of bias (information, memory), for example. Finally, this work detailing the development of the functional interview also suffers from limitations, including the need for validation and empirical testing of the FISA. These actions are planned in future projects.

This study demonstrated that it is possible to design a tool that allows for the investigation of behaviors characteristic of SAD using a functionalist model of behavior. The FISA embodies the possibility of an instrument grounded in the theoretical and methodological assumptions of behavior analysis, while also aligning with the prerogatives required by diagnostic manuals widely adopted by health professionals, such as the DSM-5, making the functional investigation of socially anxious behavior patterns feasible in clinical contexts.

Future research may also compare the use of the FISA with other instruments recognized as gold standards for the diagnosis/severity assessment of SAD to determine its reliability, sensitivity, specificity, and accuracy. These investigations could also evaluate correspondence between the diagnosis of SAD according to DSM-5 criteria and socially anxious behavior identified through functional criteria.