Malhotra AK, Breier A, Goldman D, Picken L, Pickar D. The apolipoprotein E epsilon 4 allele is associated with blunting of ketamine-induced psychosis in schizophrenia. A preliminary report. Neuropsychopharmacology. 1998 Nov;19(5):445–8. doi: 10.1016/s0893-133x(98)00031-1. PMID: 9778666.