Abstract:

In recent years, researchers have begun to study the causes of depression from the perspective of social identity (The Social Identity Approach). These studies suggested two broad categories: single-multiple and static-dynamic. Single-multiple refers to whether researchers focus on the degree of individual identification with a particular group or the number of groups that individuals identify with when examining social identity. Static-dynamic focuses on an individual’s identity at a specific time or an identity change before and after life transitions (such as further education, immigration, and others). Therefore, the investigation of social identity can be divided into four situations: static single (identity degree), dynamic single (identity importance), static multiple (identity group number), and dynamic multiple (identity change). They had a positive effect on depression overall. However, the importance of identity in stigmatized groups and its loss in changes worsen depression. Regarding mediating mechanisms, researchers believe that social identity can alleviate depression by satisfying needs. Furthermore, it can reduce it by changing individuals' cognition and behavior. These mediating factors can be divided into three aspects: need, cognition, and behavior.
Regarding theoretical explanation, Haslam et al. (2009) were the first to propose using the social identity perspective to explain mental health phenomena explicitly. They regarded this field as an important research trend. Four theories have been proposed to explain the relationship between social identity and depression. First, the Social Cure proposes that the psychological resources associated with group identity have a protective effect on individual mental health. Second, the Social Identity Model of Depression is the first to define it from a social identity perspective, proposing four key psychological resources (meaning, social influence, social support, and belonging) for depression. Third, the Social Identity Model of Identity Change shifts to a dynamic perspective, arguing that social identity continuity and gain pathway plays an essential role in life change. Finally, the hierarchical interaction model emphasizes that social identity has different levels, and these have various underlying psychological mechanisms.
Future research should be carried out from three aspects. (1) In the deep influence mechanism of social identity on depression, we should examine whether it increases an individual's interpersonal support and sense of belonging. However, more importantly, we should examine whether the meaning (target, significance, and values) and influence (such as group norms) are beneficial to physical and mental health. When the group’s meaning and influence are detrimental to an individual's physical and mental health, social support and a sense of belonging can increase this detrimental effect, leading to increased depression. (2) Use empirical research to test the moderating factors proposed by previous theoretical explanations from three aspects: individual, group, and intergroup. Examples include group type (category/interaction group), normative content (positive/negative), identity compatibility, and the role of group performance. (3) Construct an agency-communion model of social identity affecting depression. This model could simultaneously explain the four pathways of social identity’s influence on depression, simplifying psychological resources into agency (meaning and social influence) and communion (social support and sense of belonging). Their mediating effects correspond one-to-one with the four situations of social identity. The model proposes the moderating role of the content of agency psychological resources, such as the meaning and social influence are detrimental to individual physical and mental health, the performance of group "failures," and the conflict of multiple identities.

Key words: social identity, depression, the social cure, psychological resources