It is well known that pre-synaptic PTPRD promotes the differentiation of glutamatergic synapses, and several studies link PTPRD genetic variation to psychiatric phenotypes such as schizophrenia, bipolar disorder and mood instability [75], obsessive–compulsive disorder [76,77], and weight gain with antipsychotic medication [78]. This evidence concerns the gene PTPRD and schizophrenia.