This new study on persons with early stages of memory decline showed conclusively that serotonin loss was causing the memory loss rather than the other way round... In a normal brain when a message comes via a neuron, the neuron releases serotonin at its end. This is detected by the next neuron receiving the message. Once the message is propagated, there is a serotonin transporter SERT that picks up the serotonin and takes it back to the message-sending neuron. This shows up as the flow of the chemical serotonin. The serotonin neurons and transporters reduce with age in normal persons. As the neurons die with age, the SERTs also reduce in number. One group of drugs that improve brain serotonin levels are the drugs that block the brain's reuptake of serotonin (known as SSRIs or Selective Serotonin reuptake inhibitors)... But these drugs need adequate number of serotonin transporters or SERTs in the brain to work, and that was missing among those with cognitive decline. That is probably why SSRIs do not show as much success as expected.
Without diving deep into SERT's, I quickly searched what would activate them. It appears PKC inhibitors activate SERT's. They are Quercetin and Luteolin (strongest) followed by Curcumin, Reservatrol, and Skull Cap. Interestingly, EGCG activates PKC, which probably explains why my son became more autistic on EGCG (see my previous post here). Lack of serotonin activity is probably the most important cause of autism. By the way PKC = protein kinase C.
So, the message here is take an SSRI (e.g. Lexapro) with a SERT activator such as Quercetin or Luteolin.