SIK1 and schizophrenia: Furthermore, the current study also showed that the altered SIK1/CRTC2/CREB1 and TWIST1/PI3K/Akt/GSK3β signaling pathways in the schizophrenic model rat brains could be restored by risperidone, suggesting that these signaling pathways are possible targets of antipsychotic treatment and potential diagnosis biomarkers of schizophrenia.