i find it difficult to come up with background information on the research topic of exploration of psychosocial factors that influence stigma and discrimination
I would recommend looking into social categorization and social identity theory as a theoretical foundation for examining prejudice and stigma. Social identity theory (SIT) explains how individuals classify themselves and others into social groups using perceived prototypical characteristics, and how they utilize these categorizations to navigate social settings such as the workplace (Ashforth & Mael, 1989; Tajfel & Turner, 1985). According to SIT, the self-concept is comprised two parts: a personal identity encompassing certain characteristics (e.g., bodily attributes, abilities, psychological traits, interests), and a social identity encompassing group classifications (Ashforth & Mael, 1989). The classifications frequently occur based on surface-level demographic characteristics such as race, age, or gender (Tajfel & Turner, 1985). These initial judgments can lead to identity-based subgroups in which individuals classify other members as belonging to their in-group by inferring similar deep-level characteristics (e.g., values, personality, attitudes; Carton & Cummins, 2013).
Make sure not to limit your search to the last 5 years or so, as these topics have been investigated a fair amount over the past 40 or more years. Sometimes topics seem to disappear because they were so well researched in earlier years and it becomes a matter of what still applies and what has or may have changed since then that requires research withon the context of those socialtal changes.
Start with the Bogardus social distance scale and move forward. It helps to begin with a benchmark study. The terms change over the years. another benchmark was the study of authoritarianism after WWII, to explain how Hitler became so popular in creating stigma, discrimination etc. against so many.