Neural Sensitization

Like in my last blog entry I decided to revisit my entry titled What Causes Addiction?. The third cause that article mentioned is outlined below.

The article states that "neural sensitization… [causes] pathological “wanting” to take drugs". Through repeated use addicts alter their neural pathways causing them to be extra sensitive to drugs and drug triggers. The article goes on to suggest that when these sensitive systems are triggered the response may be completely implicit. This means that an addict may take actions without being conscious of their motivations. Unlike these implicit "wanting" signals, there are also explicit "wanting" reactions that manifest as drug cravings. These are often in the forefront of the addicts mind. The article states that the implicit reactions lead to the conscious experience of craving. The article makes an important distinction between "liking" and "wanting". Although an addict may want to be sober, once their brain is triggered the implicit and explicit systems kick in and the pathological "wanting" to use begins.

"Susceptibility to sensitization is determined by a host of factors, including genes, sex hormones, stress hormones, past trauma, etc., in addition to individualized patterns of drug exposure." This statement perhaps explains why some people can use highly addictive substances like heroin and meth without becoming addicted and others claim to be addicted after their first use. Everybody is different and a plethora of factors influence how are bodies and minds will react to use. Another very interesting thing is that once sensitization occurs for one substance, it is very easily transferred to other substances. The 12-step fellowships seems to have grasped this concept and encourage all members to be entirely sober even if they only had a problem with a specific substance. Often people will switch addictions and this offers a solid explanation as to why that might occur. People who become highly sensitized to drugs may also become highly sensitized to non-chemical stress, the article states that this may be why the risk for relapse is so high during periods of high stress.

This sensitization seems to permanently affect the addict and can perhaps explain why relapse is so common even after years of sobriety. An addict will remain hyper-sensitive to drugs and drug cues as well as stress. This is why "the addict might suddenly “want” to take drugs again regardless of cognitive expectancies about “liking,” declarative goals, absence of withdrawal, etc.".

Reward Learning

In my blog entry, What Are The Causes of Addiction?, there are four causes listed. The second cause is the one I will be writing about here. 

According to the article, "drugs produce abnormally strong or aberrant associations involved in reward learning, more powerful than natural reward associations". There are two ways that this extremely strong learning system can really impact an addicts decision making. The first is that memories of the drugged experience may be extremely vivid and intrusive. The second is that drug use can alter an addicts memories, causing them to view drug use in a more positive light than is appropriate. If these two statements are true, it seems clear that this would fuel addiction. Basically, an addict does drugs and then can not stop thinking about doing the drugs. In addition, they remember the incidence in an exaggeratedly positive light, perhaps ignoring the consequences. This information seems to fit cohesively with addicts' descriptions of their use, except in the fact that they are able to logically understand and predict the consequences yet use anyways. The author suggests that perhaps the habits are so reinforced by learning that they become compulsive. It seems there must be some other piece that motivates the addict to behave in these compulsive and automatic behaviors though. Addicts put drugs ahead of everything in their lives including basic survival necessities. This suggests that the reward from drug use is superior even to the natural reward associations we need to survive. This clearly seems to be an important factor in what causes addicts to use, but there are other factors to examine.