PSD95 and similar scaffolding molecules, link the NMDA receptor with intracellular enzymes that mediate signaling; this process is involved in the development and maintenance of synaptic function and synaptic plasticity, and interference in this process is implicated in schizophrenia and bipolar disorder (Beneyto and Meador-Woodruff 2003). This evidence concerns the gene DLG4 and schizophrenia.