An acute excessive elevation of serotonin levels can produce over-stimulation. This is often referred to as serotonergic syndrome.For example, combining SSRIs with other drugs that potentiate sertonergic neurotransmission (such as other SRIs, MAOIs, tryptophan,buspirone) may produce this syndrome, "characterized by severe GI symptoms, autonomic instability, and neurospsychiatric side effects, including delirium." I am not sure if this overstimulation may also be related to the lowered seizure threshold some individual's experience when taking SSRIs or other serotonin elevating drugs. Linda Walsh University of Northern Iowa
