The correlation analyses revealed a crucial positive association of serum IGF-2 levels with the working memory index (r = 0.546, p = 0.001), the attention index (r = 0.405, p = 0.021), and the executive function index (r = 0.606, p < 0.001) in the schizophrenia patients (Table 4). Here, IGF2 is linked to schizophrenia.