This is here because of a search I did on "paradoxical effects" of psychiatric medications. What I found was an article written by J K Palmer, associate professor of psychology, at Eastern Kentucky University.
The article is interesting and relevant since the article first talks about the brain's neurons communicate with one another, and how drugs affect that communication process. Read down and you'll find that a chemical known as Acetylcholine is used by the neurons that control your muscles, heart, and lungs. It is also used by many neurons in the brain that are involved in memory. Acetylcholine crosses the brain synapses and tells the muscles to extend by stimulating the receptor sites on the muscles.
When nerve signals are terminated this is called “reuptake”. Acetylcholine is rapidly broken down by a chemical called acetylcholinesterase. Have you ever looked at the fine print on a bottle of Prozac, Paxil, or Zoloft? It says in there that the drug is a “selective serotonin reuptake inhibitor” (SSRI).
Now, read the fine print on a can of insecticide. For some of them, it says that the active ingredient is an “acetylcholinesterase inhibitor”. So, the same effect that we see with bug spray, can be facilitated by SSRIs. You do the math.
As an FYI, nicotine directly stimulates acetylcholine receptors. Alzheimer’s disease results when these acetylcholine-using neurons in the brain die. [As an aside, does this new info about bug spray provide us any fresh insights on the actions of former US Senator and insect exterminator Tom DeLay?]