What about a severe LACK of serotonin, especially in the presence of SSRIs?
I am not familiar with that syndrome. However, if this does exist the SSRIs would be helpfull. The mechanism of Serotonin Specific Reuptake Inhifitors SSRIs is to decrease the amount of serotonin that is taken back out of the synapse into the neuron. It does not change the total amount of serotonin in the body but keeps more in the synapse thus in effect increasing the amount of the neurotransmitter that is available to carry the signal across the synapse. The neurotransmitters in the synapse are constantly taken up into the neuron and recycled as needed into the synapse. This is how an electrical signal in the neuron "jumps" the gap between them. The serotonin will go from one neuron to the next neuron and this will cause an electrical signal to go down the second neuron.