Effects of Long-Term Administration of Antidepressant Drugs on the Serotonergic System



Antidepressant Treatment Responsiveness of somatodendritic 5-HT (1A) autoreceptors Function of term'l 5-HT autoreceptors Function of term'l adrenergic receptors Responsiveness of postsynaptic receptors Net serotonin transmission 5-HT receptors
selective serotonin reuptake inhibitors
decreased
decreased
no change
no change
increased
monoamine oxidase inhibitors
decreased
no change
?
no change or decreased
increased
monoamine oxidase inhibitors
decreased
no change
?
no change or decreased
increased
5-HT (1A) receptor agonists
decreased
no change
no data
no change
increased
tricyclic antidepressants
no change
no change
no data
increased
increased
electroconvulsive shocks
no change
no change
no change
increased
increased
Adapted from Kandel et al's Principles of Neural Science

The table above shows a comparison of how different types of antidepressant drugs (as well as electroconvulsive shock therapy, which has been shown to be effective, for comparison) affect different aspects of the serotonergic system. Since the three categories of antidepressant drugs work in similar ways (although successively with more specificity) it may be useful to see the progression of effects that each has.