Substance abuse reinforcement

Abused drugs generally produce pleasant effects that are desired by the user. However, while most individuals will experience these pleasant effects, not everyone abuses these drugs, and not everyone who abuses them becomes dependent on them. Why some persons abuse drugs while most people do not is a complex area of research. It appears that genetic, environmental, and cultural factors may all interact to predispose some individuals to substance abuse and subsequent dependence. The initial hedonic experiences secondary to use of drugs appear to be primarily due to their ability to activate the primary reward circuits in the brain. These same reward circuits operate under normal circumstances to reinforce certain activities that promote survival, such as food, social affiliation, or sexual activity. 

The recent approval of the SNRI duloxetine for the treatment of diabetic neuropathy reinforces the utility of this drug class in the treatment of neuropathic pain. Other largely untapped areas which remain to be exploited with this drug class include sexual dysfunction, such as premature ejaculation, irritable bowel syndrome, obesity, neurodegenerative diseases such as Parkinson s disease, restless leg syndrome, and substance abuse and addiction. It is apparent that considerable opportunities for drug discovery will exist in this area for some time to come. 

Dailey, Jeffrey W., Tim D. Fryer, Laurent Brichard, Emma S. J. Robinson, David E. H. Theobald, Kristjan La e, et al. Nucleus Accumbens D2/3 Receptors Predict Trait Impulsivity and Cocaine Reinforcement. Science 315 (March 2,2007) 1,267-1,270. The researchers report on evidence that indicates the state of dopamine neurotransmission may be an important factor leading to substance abuse problems. 

Another consideration in the choice of benzodiazepine is their potential for abuse. Individuals with addictive disorders prefer certain agents to others. Agents with rapid onset of action, such as diazepam or alprazolam, demonstrate higher abuse potential because of their reinforcing effects. Those with slower onset of action, such as chlor-diazepoxide, oxazepam, and halazepam, are less likely to be abused. This consideration may be relevant in an outpatient setting or for patients with a history of benzodiazepine or other substance abuse. ... 

At this point, counseling can help restore constructive parenting around the substance-abusing child. Why is this so important Because it s very hard for an unhealthy-acting boy or girl to get well in a family system that either models or reinforces its own unhealthy behavior. When parents are helped to replace their confused, inconsistent, and enabling conduct with firm and constructive stands, the afflicted child is given a healthy set of rules and expectations that he or she can choose to live by. 

Withdrawal of the abused substance results in a decrease in the large quantities of dopamine resulting from the drugs. The substance-dependent person experiences symptoms of depression, fatigue, and withdrawal. The only way to relieve these symptoms is to use increasing quantities of the abused substance of abuse, reinforcing dependence on the drug. 

Toluene, volatile nitrites, and anesthetics, like other substances of abuse such as cocaine, nicotine, and heroin, are characterized by rapid absorption, rapid entry into the brain, high bioavailability, a short half-life, and a rapid rate of metabolism and clearance (Gerasimov et al. 2002 Pontieri et al. 1996, 1998). Because these pharmacokinetic parameters are associated with the ability of addictive substances to induce positive reinforcing effects, it appears that the pharmacokinetic features of inhalants contribute to their high abuse liability among susceptible individuals. 

That impression gets of a lot of routine reinforcement from news sources. Chemistry is associated with pollution of the atmosphere by ozone and the noxious oxides of nitrogen and sulfur, oil spills, toxic pesticides and herbicides, smelly oil refineries, undesired food additives, chemical accidents, substances of abuse such as heroin, cocaine, and methamphetamine, and chemical weapons. Chemistry gets a lot of bad ink. 

---