Why do some people become addicted to smoking
There are many people in this world who are smokers, however not all the people who smoke or drink become addicts. This phenomenon of addiction to a particular activity is generally associated with the individual’s mind set too. However to throw more light into this aspect, scientists conducts studies to become more familiar with the biochemistry of both healthy and addicted brains, to tease out some of the differences between people who become addicted and those who do not.
Drugs themselves are not sufficient to cause addiction. A person’s environment and genes also influence the likelihood a person will become an addict. With that view in mind, scientists have been looking for a biochemical factor that could incline someone to addiction. One protein that fits that description is the dopamine receptor. Dopamine is one of the major neurotransmitters in the brain and is involved in pathways that sense pleasure and reward.
The dopamine receptor, D2, lies on the far side of neural synapses in the brain and binds dopamine as it is released by the neuron; binding of dopamine by the receptor transmits the electrical activation of one neuron to the next. Addicts generally have less D2 in their brains than do healthy controls. Interestingly, though, there is overlap, suggesting that D2 levels are not an absolute indicator of addiction. The levels of D2 appear to play a role in addiction, but are not sufficient to cause it.
The level of D2 plays an important role in how someone senses reward or value for a stimulus. At normal levels of D2, most people will feel a sense of pleasure or reward from food, social interaction, or sex. If the level of D2 is too low, however, then this sense of reward wouldn’t occur in response to such natural stimuli.
Addictive drugs, however, increase the amount of dopamine that is released in the synapse relative to natural stimuli. These unusually high levels of dopamine make up for the lower levels of D2 receptor and induce a sense of salience for the addict. The people with lower levels of D2 liked the drug; those with higher levels did not.
The natural variation in D2 levels in the population may be important for who becomes an addict. For those people with higher D2 levels, the drug stimulus was so strong that they felt uncomfortable and would not be inclined to try it again, but for those with a lower receptor level, the drug created a pleasant sensation.
Thus this work is beginning to draw a picture of why some people become addicted while others do not, and of what happens when they do. Such research may enable clinicians not only to treat addiction but to prevent it.