Figure 9.

The drug-induced relative nutritional deficiency. When the monoamines are in the vesicles of the presynaptic neuron, they are not exposed to the enzymes that catalyze metabolism (monoamine oxidase and catechol-O-methyltransferase). They are safe from metabolism. When they are relocated outside the vesicles of the presynaptic neuron, they are exposed to these enzymes at a greater frequency. Reuptake inhibitors create a mass migration of monoamines causing increased metabolic enzyme activity and metabolism of monoamines. This leads to the drug-induced relative nutritional deficiency if significant amounts of balanced serotonin and dopamine precursors are not coadministered with the reuptake inhibitor.