AMPH and psychotic disorder: No significant elevation of the sphingolipid enzyme activities was found 14 days after psychosis induction (p > 0.05; Fig. 4g–k), where only a decrease in AC activity in the VS was observed (F2,25 = 4.518, p = 0.021; AMPH-VEH vs SAL-VEH: p = 0.009, Fig. 4i).