Tolerance plays a very big role in addiction. Tolerance is progressive and the timeframes vary which depend on the physiological structure of the individual’s makeup and the type of substance that they are using. What typically happens in the pattern of addiction is someone will use a substance to experience a high or at least some effects that the substance has to offer. Overtime, the amount that they started with will not give them the effect that they had been getting so they will up their dosage. This will continue inevitably. For example, if a 21 year old drinks only 2 beers each night as a way to decompress, overtime, those 2 beers will not have any effect of them at all. If every 5 years, that same person ups their amount by only 1 drink to reach the desired effect, then by the time they are 41 years old, they will be drinking 6 beers every night. 6 beers every night can cause a lot of physical problems, not to mention can be very expensive. This is just an example of a slow progression of addiction. Of course, other substances such as crystal methamphetamine will have a much faster tolerance and physical effect. This is significant in the progression of addiction because if tolerance did not occur, addiction may not have consequences. 2 beers a night may be okay over one’s lifetime and would likely not involve legal or lifestyle consequences. 6 beers could cause someone to get a DUI, spend too much money, or lose their job.
Tolerance of a drug can be defined in two ways. First, it can be defined as the decreased effectiveness of a specific amount or the body’s need to increase the dose to maintain the effectiveness. There are a few types of tolerance such as metabolic, physiological, general or nonspecific tolerance and specific tolerance.
Metabolic tolerance is when the body learns to metabolize the drug quickly. When the action of an enzyme is induced this will increase the action that the body needs to destroy it.
Physiological tolerance is when homeostasis mechanism controls the body in a way that is making up for the negative responses that a drug produces. Homeostasis is able to create a new “set point” in the body that is acquired when the drugs enter. This is why a person will need to eventually take more drugs to get high or will experience the negative withdrawal symptoms when they stop taking the drugs.
General or nonspecific tolerance is a combination of physiological mechanisms. Specific tolerance is related to just one type of tolerance. Behavioral tolerance is a conditioning process that is learned. Depending on a person’s background or environment in which the drug use took place a person’s behavior can affect the way they act when they are tolerant.
Tolerance relates to addiction. When a person becomes tolerant of a drug or alcohol they have two choices. They can stop because it is a waste of time and money for no pleasurable gain or they can up their dose to continue the pleasurable route. If they choose the latter this could activate the positive reinforce of the brain thus resulting in addiction.
Incentive sensitization is a new theory in addiction in which it is believed that the more a user uses a drug the drug will become sensitized. When a person uses a drug the positive reinforcers become stronger with every use. This will then lead to more and more usage of the drug. This means that anything that is associated with that drug can make a person sensitive and crave the situation or experience they had when they were having fun. Even though tolerance may occur, a user of a drug will crave the experience more and more. This theory includes the definition of incentive salience which is when the stimulus is noticed and activates behavior that is associated with it. The more a drug is used, the more of a reinforcer it becomes. For example, if food is the positive reinforce in someone’s life and they try a drug for the first time, food is still going to have the most effect on a person’s behavior. However, when taking a drug again and again it will not be able to compete with other positive reinforcers and will be able to control a person’s behavior.