Multidimensional analysis of social withdrawal in the sub-chronic phencyclidine rat model for schizophrenia.

rationaleSocial withdrawal in the sub-chronic phencyclidine (PCP) rat model—a behavioral correlate of schizophrenia’s negative symptoms—is well characterized, yet the psychological mechanisms underlying this deficit remain unclear.

objectivesDespite the complexity of social behavior, assessments often rely on a single metric (e.g., total interaction time) that has limited explanatory power, thus limiting insight into the underlying processes. This study aimed to address this gap through a multidimensional behavioral analysis.

methodsWe developed a detailed ethogram encompassing both social and non-social behaviors (e.g., self-directed actions and environmental exploration) within the dyadic social interaction paradigm. Specifically, we defined 42 behaviors (or behavior groups), 28 of which were social, organized into five categories: Avoidance, Risk Assessment, Approach, Recognition, and Contact. Behavioral scoring was performed manually using ANY-maze and supplemented with automated tracking via EthovisionXT, enabling a comprehensive analysis of saline- and PCP-treated rats (5 mg/kg, twice daily for 7 days, followed by a washout).

resultsPCP-treated rats exhibited a significant reduction in overall social interaction compared to controls, with selective impairments in specific behaviors (e.g., Following) but not others. Notably, these animals demonstrated a persistent attentional bias toward the inanimate environment—evident during both habituation and social exposure phases—suggesting a displacement of attention away from conspecific engagement.

conclusionsOur findings reveal a nuanced behavioral phenotype in PCP-treated rats, characterized not only by reduced social interaction but also by altered attentional allocation. These findings deepen our understanding of the neuropsychological mechanisms underlying PCP-induced social withdrawal and its relevance to schizophrenia.