Even though we have not discussed this topic broadly, we have seen a video of it and it caught my eye, therefore I chose this topic. It is critical to understand the distinction between drug abuse and addiction as abuse and addiction are separate diagnostic categories. Abuse describes the use of mood - altering drugs in such a way as to cause some level of dysfunction in the individual's life. In contrast, addiction (which may vary in severity) describes a process of compulsive use of drugs, loss of control over the drugs or over drug-induced behavior, and continued drug use despite adverse consequences. During drug use and drug abuse, the behavior controls the drugs. Although it may be a poor idea, the decision to abuse drugs is made by cortical areas of the brain: those areas concerned with rationality and logic. In contrast, addiction is characterized by the drugs controlling the behavior. In particular, addiction is controlled by deeper, more primitive, lower centers of the brain (Suojanen, 1993). The addicted person's compulsion to use the chemical arises from more primitive central nervous system instinctual centers, where imbalances in neurotransmitters occur (Morrison & Smith, 1997). In other words, for the addicted person, the choice to use or not use drugs no longer exists, and continued drug use precludes logical and rational thought processes (Talbott, 1994). One way of describing this phenomenon is to say that people who abuse drugs can "cross the line" into addiction, but cannot cross back into controlled use. Neurobiology of Drug Addiction
From the neurobiological point of view, drug addiction can be defined as a chronically relapsing disorder that can be defined as a compulsion to take a drug with loss of control over drug intake. Important challenges for neurobiological research are to understand not only how drug use proceeds to drug addiction but why some individuals have a vulnerability for the transition that occurs between controlled substance or drug use and the loss of control that defines addiction or substance dependence. Progress in understanding the neurobiology of drug dependence has depended not only on the development of molecular, neurobiological, and neuropharmacological tools for understanding the neuropharmacological mechanisms of action of drugs of abuse, but also the development of animal models of drug dependence that allow interpretation of neuropharmacological advances in the context of the disorder under study. An important issue in such a multidisciplinary pursuit is that an operational framework from which to derive animal models is needed. The motivating factors for the development, maintenance, and persistence of drug addiction can be broken down into four major sources of reinforcement in drug dependence: positive reinforcement, negative reinforcement, conditioned positive reinforcement, and conditioned negative reinforcement (Wikler, 1983) For instance, nicotine has an initial molecular site of action as a direct agonist at nicotinic acetylcholine receptors. Although brain nicotinic acetylcholine receptors are widely distributed throughout the brain, to date it is the receptors specifically in the brain mesolimbic dopamine system that have been implicated in its reinforcing actions. Interestingly, nicotinic acetylcholine receptor antagonists and opioid peptide antagonists can precipitate a physical withdrawal syndrome in rats (Malin et al., 2004). Thus, nicotine may alter function in both the mesocorticolimbic dopamine system and opioid peptide systems in the same neural circuitry associated with other drugs of abuse (Corrigall, Franklin, Coen, & Clarke, 2002). Neurotransmitters
Neurotransmitters, are naturally occurring brain chemicals that are necessary for the transmission of nerve messages in the nervous system. Because these chemicals are essential to the...