Approach and avoidance in schizophrenia: The influence of comorbid social anxiety disorder and of social anxiety symptoms severity.

People with schizophrenia spectrum disorders (SSD) frequently present with a comorbid social anxiety disorder (SAD), which is associated with increased functional impairment, potentially due to heightened social avoidance. Individual differences in approach and avoidance can be conceptualized using Gray's revised Reinforcement Sensitivity Theory (RST), which describes three interacting motivation systems: the Behavioral Approach System (BAS), the Behavioral Inhibition System (BIS), and the Fight-Flight-Freeze System (FFFS). This case-control study examined approach and avoidance in people with SSD and the impact of SAD in 42 individuals with SSD and 42 community controls (CO). Social anxiety was assessed using the Liebowitz Social Anxiety Scale (LSAS) and the Structured Clinical Interview for DSM-5 (SCID-5). Approach and avoidance motivations were assessed using the Reinforcement Sensitivity Theory Personality Questionnaire (RST-PQ). Fifteen participants with SSD and six CO met the diagnostic criteria for SAD. A significant group effect (SSD > CO) was observed for both the BIS (p = 0.003) and the FFFS (p < 0.001), while an effect of social anxiety (SAD > no SAD across groups) emerged only for the BIS (p < 0.001). No significant effect emerged for the four BAS scales. Social anxiety symptom severity was positively correlated with BIS scores for both groups (ps < 0.001) and negatively correlated with BAS-Reward Interest scores only for the SSD group (p < 0.001). These findings emphasize the role of social anxiety in shaping approach and avoidance motivations, a factor particularly relevant given its high prevalence in SSD.