Fairleigh Dickinson University
In a Biology Today: An Issues Approach, a textbook published in 2004, addiction was defined as a “compulsive physiological and psychological need for a substance”(Minkoff & Baker, 2004). Using this definition, researchers have tried to understand and prevent addiction.The American Society of Addiction Medicine has made corrections to its old definition of addiction. The new definition shifts the focus from drug dependency to the alterations in brain’s reward system (Smith, 2012) .
Addiction research should not be about which substances and what quantities were used. It is about what happens in a person’s brain when they are exposed to rewarding substances or rewarding behaviors, and it is more about the reward circuitry in the brain and related brain structures (Smith, 2012). The previous research under the old definition has resulted in knowledge about how psychoactive drugs affect the reward circuitry in related structures of the brain. This will be covered in more detail in a separate section. From this extensive research, the ASAM recognizes the importance of memory, motivation and related circuitry in the manifestation and progression of this disease (Smith, 2012).
The problem with the ASAM’s old definition is that the focus has been on trying to repair neurotransmitter imbalances. Psychoactive drugs have physical effects when the active drug and inactive. With the old definition, addiction treatment was complete when the withdrawal symptoms were treated. There was medicine to immediately induce vomit when an alcoholic drinks alcohol (disulfiram). All the developments have still proved unreliable in completely curing substance dependence or substance addiction (Vaillant, 2005). Addicts were still seeking out these rewarding behaviors. The old definition also could not clearly distinguish substance addiction from other kinds of behavioral addictions such as sex and gambling. This was problematic since both addictive behaviors, considered separate, had serious negative social consequences and relapse rates were significant.
There was separate research going on for gambling and sex addictions. Researchers at Penn State (Puhl et al., 2008) noted that food addiction affects the brain’s reward circuitry in a manner that memories of previous experiences trigger cravings and more addictive behaviors. The same study noted the brain circuitry that governs impulse control and judgement in the brains of food and gambling addicts is also altered the same way in brains with drug dependency. This alteration is evident in the both addict’s senseless pursuits such as gambling when already in debt or stealing for drugs. The new ASAM definition makes a departure from equating addictions with just substance dependence, by describing how addiction is related to behaviors that are rewarding. (Smith, 2012) The new definition is the first time that the ASAM taken the official position that addiction is not just substance dependence.
We all have the brain reward circuitry that makes food and sex rewarding. In fact, this is a survival mechanism (Smith, 2012). An addict’s brain and a healthy one both perceive rewards the same way. When an external stimulus such as as the smell of a food or sight of a potential mate is encountered and deemed a pleasurable sensation, the cerebral cortex signals to the ventral tegmental area of the brain to release the chemical dopamine into the amygdala, prefrontal cortex and nucleus accumbens. These areas work in conjunction to deliver a sense of pleasure and focus the attention of the individual so that he or she learns to repeat the behavior once more. In a healthy brain, these rewards also have feedback mechanisms signaling “enough” so the brain knows to stop seeking these rewards. In an addict’s brain, researchers are unsure how but the feedback mechanisms are dysfunctional. When there is a reward in