**4.1. Symbolic interactionism theory**

This theory focuses on explaining how people create their own identity and define themselves through their social experiences, that is, through their interaction with other people. Society is understood as a result of everyday, face-to-face, interaction among people. Through this interaction, people define and give meaning to the social world in which they live [14].

Symbolic interactionism is based on multiple premises. The most relevant and useful scenarios [15] for the study of HIV are: 1. Human beings react in one way or another depending on their perception of the object, person or situation they face, that is, the meaning they prescribe to a situation. 2. The individual (subject) adopts an active role in creating meanings. 3. Things do not have an inherent meaning; the meaning of things arises or emerges as a consequence of the social interaction established between people. 4. Meanings are handled in and modified through an interpretative process carried out by the person. 5. Common meanings make communication between human beings possible.

In summary, according to this theory, social reality is symbolically created during the course of social interaction and is therefore subject to change. Human behaviour is social and is based on communication; therefore, people create and interpret social situations and their meanings during this communicative process. It is during the course of social interaction that objects gain meaning for the person or persons. These social meanings are created and modified during the dialogue of social interation.

Thus, the symbolic interactionist perspective is especially useful in the construction of behaviour, as it gives a primary role to the concept of the interaction that occurs between the members of a social group. Furthermore, "human beings interpret or define the actions of others, without being limited to simply reacting to them. Their response is not directly elaborated as a consequence of the actions of others, but is based on the meaning they give to such actions" [15]. Therefore, in relation to health and disease, and the prevention of HIV, this theory constitutes an important theoretical perspective for studying and explaining the social conduct of people and groups of people who interact with each other on the basis of sharing symbolic meanings. In the field study of HIV, symbolic interaction theory has been extensively applied [16]. This theory is useful for studying the stigma that exists among people living with HIV. Recently, it has been published a meta-analysis about ART non-adherence. The results of the study suggest that the existence of stigma is a factor of non-adherence [17]. This systematic review identified 34 studies that applied this theory. These studies indicated existing intrapersonal, interpersonal and structural barriers as a result of stigma as factors of non-adherence [17].

The process of social interaction constitutes a fundamental aspect in the study of the doctorpatient relationship. Since communication does not have a unidirectional character, the emission and reception of messages does not occur in a passive way. Such constant feedback creates a process that influences the way in which the disease and the person's subjec‐ tive experience are created. This theory has been used to study the relationship between people infected with HIV and health professionals [18]. Recently, an interesting study conducted in Spanish health services analysed the relationship between people living with HIV and physicians as it concerns interventions developed within the areas of sexuality and safe sex [19].

Hence, symbolic interaction allows for a broader view of the approach to doctor-patient interaction, because it enables an understanding of the processes of social interaction that take place during the course of the relationship (doctor-patient). Subsequently, it also allows for an analysis of the role of the patient and health professionals in their encounters throughout the disease process. Furthermore, the communicative process that is established motivates the participation of other people, the family and the community. Therefore, the meanings and the subjective experiences of HIV-positive people are created during the social interaction process, not only with health professionals, but also with other individuals and groups with whom the HIV-positive person interact in normal everyday life. In this sense, studying doctor-patient interaction is useful for identifying the potential cultural barriers that can arise from this interaction. For instance, Spain recently conducted a research study, the objective of which was to understand and analyse the experience of immigrant HIV-positive women with health professionals and treatment services [20].

The fundamental contribution of symbolic interaction to the field of social cognition is the consideration that mental processes are the product of symbolic interaction and not of internal individual processes [21]. Emotions are an example of mental processes that have been studied from a symbolic interaction approach, given that they are expressed in response to social relationships or situations, or both. Human interaction possibly plays the most important role in the activation and expression of emotions [14]. Thus, emotions are biological responses to social situations and the interaction between the people involved in such situations. From this perspective, health and disease are understood as human constructions perceived in a subjective manner by the population. It entails analysing peoples' everyday views of disease, the ideological connotations that health professionals attach to diseases, and the construction and application of medical knowledge [22]. Altogether, according to this theory, it is possible to analyse aspects that are relevant for the study of the HIV phenomenon, such as the different constructions created by people in their interaction with others, the meanings, perceptions, life experiences, beliefs, values in relation to HIV, guilt feelings for being HIV-positive, stigma, risk perception, as well as reasons for abandoning treatment.
