Posted by PaulB on July 3, 2001, at 15:18:01
In reply to why do antidepressants work?, posted by Edward on July 3, 2001, at 14:32:39
> I don't understand this: whenever you take drugs constantly for a prolonged period of time, you become tolerant. You need more to produce the same effect until eventually you need to take the drug to be normal. This happens with any intoxicant. So why not with antidepressants? Surely if you take something that increases your serotonin levels for a long time you will become tolerant and it will lower your serotonin levels. Can anyone explain this to me?
Some drugs bind to the receptors that neurotransmitters latch onto in the brain like benzodiazepines and opiates and some drugs provide a massive release of neurotranmsitters like Amphetamine and MDMA. After exposure to these drugs for a while the no of receptors and their sensitivity will lessen causing tolerance like you mentioned. Antidepressants are different. They just allow the brain to make better use of what neurotransmitter is already present. They are not supposed to produce a high and that is why they take 2-4 weeks usually to start working so that the brian can adjust to a more normal level of neurotranmsitter. When they start working in a depressed person there is just an increase in neurotransmitter that locks into the receptor like in any healthy person. The re-uptake or MAO inhibition compensates for the faulty mechanism via which neurotransmitters are constantly recycled. Thats one theory anyway.
poster:PaulB
thread:68829
URL: http://www.dr-bob.org/babble/20010701/msgs/68838.html