Why Doesn't it Last? The Brain's Ups and Downs
Why do you need more and more caffeine, nicotine or alcohol to get the same effect? Remember the kick from your first cigarette? Have you ever wondered why you don't experience that any more?
The brain has a set of negative feedback mechanisms whose goal is to prevent us from being too stimulated for too long. When we boost our feel-good neurotransmitters, as we do with a cup of coffee, the dopamine released causes a feeling of well-being. However, in response, the receptors gradually shut down, deflating our high.
A key concept in the body and brain, as in all of nature, is balance. Much as a thermostat keeps our home at a desired temperature, our body has ways of maintaining a state of equilibrium. It doesn't want us to be too high for too long!
So, in response to an increase in the amount of neurotransmitter available, for example dopamine from drinking coffee, there is a 'downregulation' of the receptor sites. This means that some receptor sites shut down, making the neuron less responsive. Consequently you need more of the stimulant - caffeine, nicotine, cocaine, whatever - to release neurotransmitters into the synapses and get the message across. It's as if to block out the yelling of the nerotransmitters the receptors put on earplugs, leaving the neurotransmitters no alternative but to yell even louder.
The body's self-regulation process, then, makes it impossible for us to gain any long term benefit from the use of stimulants. Herein lies the rub.
The net result of addiction is that once the initial effect has worn off, the body's normal production of dopamine - its usual 'talking voice' - just isn't loud enough to get the now somewhat deaf neighbouring cells excited. As a consequence, you feel tired, lacking in motivation and in need of another hit of stimulant. And as time goes on you need more and more. No longer will that cup of coffee (around 100mg of caffeine) give you the kick-start you need. You need a large 'special' coffee (around 400 mg), perhaps with a cigarette thrown in, or even a mochaccino (chocolate plus coffee, two different sources of caffeine).
Of course, the more you have and the more often you have it, the more your brain cells 'down regulate' by shutting down receptor sites. Continue along this slippery path for long enough and the effects of the stimulant become nothing like they used to be. No longer does that cup of coffee geive you a rush of energy. Now all it does is relieve your ever-increasing fatigue. You need coffee just to feel normal, let alone good. You've been trying to cheat the system and it's fighting back. Crime, as far as falsely stimulating your neurotransmitters are concerned, doesn't pay.
Unfortunately, by the time you realise this and stop using the substance, your body's chemistry doesn't give you an unconditional pardon. Instead, it punishes you with withdrawal. In effect, the withdrawal period is the time it takes from the moment you quit using stimulants until your neurons 'upregulate' to hear you neurotransmitters' normal speaking voice once again. In the case of caffeine this is only a matter of days. For nicotine or heroin it can take weeks.
Natural Highs -
Patrick Holford & Dr Hyla Cass
