Usually, both physical and psychological components need to be addressed. Byrd (2001) explains, the function of brain cells (neurons) is affected when a drug is used repeatedly over a long period of time. Each neuron produces and releases chemicals called neurotransmitters. These neurotransmitters can impact the function of the nerve cell, making it produce and release hormones. "The neurotransmitters that have been associated with addiction include serotonin, dopamine, norepinephrine, gamma-amino-butyric acid, and glutamate" (p. 71). Drugs and the secretion of neurotransmitters can interfere with nerve cell functions and in some cases can damage them. Addiction becomes a fact when the body increases its level of resistance to immediate drug effects and develops a tolerance for the substance. As this happens, the brain tries to maintain a normal state, but the nerve cell membrane is changing. "Release of dopamine affects the part of the brain that regulates motor behavior. The destruction of the neurons that produce dopamine by substance abuse produces symptoms of Parkinson's disease, such as rigidity and tremor" (Byrd, 2001, p. 65). Byrd (2001) explains that dopamine's role is to trigger the creation of a "memory of pleasure." The next time the person thinks about taking the drug there is an anticipation of pleasure already present. The Merck Manual of Diagnosis and Therapy (2006) explains, "A neural substrate for reinforcement (the tendency to seek more drugs and other stimuli) has been identified in animal models. In these studies, self-administration of such drugs as opioids, cocaine, amphetamine, nicotine, and benzodiazepines is associated with enhanced dopaminergic transmission in specific midbrain and cortical circuits. This finding suggests the existence of a brain reward pathway involving dopamine in the mammalian brain" (p. 1684).

As to the psychological aspects of addiction, the Merck Manual of Diagnosis and Therapy claims there is little scientific evidence that an "addictive personality" exists, although behavioral scientists have described it. Addicts are described as escapists, "people who cannot face reality and who run away" Others describe them as having schizoid traits -- "...fearfulness, withdrawal from others, feelings of depression and a history of frequent suicide attempts and numerous self-inflicted injuries" (p. 1685). Sometimes addicts are pictured as dependent and needy, grasping in relationships, and full of overt "unconscious rage and immature sexuality" (p. 1685). However, Merck points out that before these people got involved with drugs, they generally did not exhibit manipulative, "irresponsible behaviors" (p. 1685), so it's possible, if not probable, that these characteristics are related to the drug abuse and not part of the addict's basic "before-drugs" personality.

Drugs with Addictive Potential

The most commonly used drugs that lead to addiction on the market today are narcotic analgesics, also called opioids. Some of these are morphine, codeine, OxyContin, Vicodin, Demerol, Percadan, Percacet, Lortab and Dilaudid (Sverdlik, 2005; and Meadows, 2001). Currently, the most popular of these are OxyContin and Vicodin, which contain oxycodone HCI, an opioid similar to morphine in its addictive potential. Mortality and criminality are also associated with abuse of these drugs. Opioids work by blocking transmission of pain messages to the brain. A large single dose can produce euphoria, but can also depress respiration and cause death. Long-term use usually leads to physical dependence (Meadows, 2001).

Another class of drugs, to which people become addicted, is central nervous system depressants (tranquilizers, sedatives, and sleep aids). Usually, they are prescribed for anxiety, panic attacks, and sleep disorders. Nebutal, Valium, and Xanax are examples of central nervous system depressants that slow down normal brain function. The effect is usually a sleepy and uncoordinated feeling. Long-term use of these can also lead to physical dependence and addiction (Meadows, 2001).

A third category of drugs favored by drug abusers is central nervous system stimulants. These drugs were developed originally as "diet pills" because they lessen hunger. They are commonly used to treat narcolepsy, a sleeping disorder, and attention deficit hyperactivity disorder. Dexedrine and Ritalin are examples of CNS stimulants. People take them to increase alertness and energy, or to control their weight, but they elevate blood pressure, heart rate, and respiration and can be addictive. High doses can cause irregular heartbeat and high body temperature.

Longo et al. (2000) points out that all three categories of drugs have certain common characteristics. Self-administration studies have shown they are preferred over placebo, especially by patients who are addicted or...

Although they affect different areas of the brain, they all cause dopamine release -- the "reward" pathway in the brain that causes anticipation of pleasure. All are habit-forming, lead to dependence, and have psychoactive effects. All of them have street value and a potential for abuse. Moreover, brand name drugs are worth more on the street than generic equivalents are because people feel sure they are getting the real thing.
Generally, addicts prefer drugs that have "a rapid onset of action, high potency, brief duration of action, high purity, water solubility (for intravenous use) or high volatility (ability to vaporize if smoked)" (Longo et al., 2000, p. 2402). Among benzodiazepines, Valium, Ativan and Xanax cross the blood-brain barrier more rapidly and have a high potential for abuse. Longo argues that a significant number of addicts started out using street drugs and progressed to prescription drugs as they became chronically ill. Sometimes, prescription drugs are used in conjunction with street drugs to heighten euphoric effects, alleviate withdrawal symptoms, augment alcohol effects synergistically, or temper cocaine highs.

Prescription Drug Abuse by Adolescents, Women, and the Elderly survey in 2002 at a rural Michigan high school revealed that 98% of the pupils knew about OxyContin, and 9.5% had tried it. Among those who had tried it, 50% reported taking it more than 20 times. Among the students who responded to the survey, 72% said OxyContin was "not at all hard to get..." (Katz & Hays, 2004). Adolescents are certainly not the only ones abusing OxyContin, but they seem to be more vulnerable to addiction. "The time from first exposure to abuse of or dependence on OxyContin may be more rapid due to (1) the wide availability of the drug in pharmacies and doctor's offices and on the street; (2) its aggressive marketing and promotion in an atmosphere of optimal pain management; (3) its positive image in comparison to heroin; (4) the ability to begin use with oral ingestion and to progress to snorting or intravenous use; and (5) the ease with which the tablet is crushed, thus destroying the controlled-release coating and making the active ingredient immediately available for a powerful heroin-like high" (Katz & Hays, 2004, p. 232). Because we live in a "pain culture" where young people constantly see reliance on pain medications modeled by adults and encouraged in media advertising, prescription drugs may seem more acceptable to adolescents than illegal drugs.

Women also appear to be more vulnerable to opioids than men. Carlson, Eisenstat, and Ziporyn (2004) call mood-altering drugs -- especially sedatives and tranquilizers -- a "major substance abuse problem" (p. 581). This may be because mood-altering drugs are often prescribed earlier -- at a younger age -- for women than for men. They are also prescribed more frequently for women, perhaps because women are more likely to seek help for emotional problems than men are. The opioids have a higher risk for dependence, especially if the woman has chronic pain. Women are also more likely to abuse diet pills (CNS stimulants). They start taking them for appetite suppression and weight control, despite the fact that amphetamines are rarely effective in the long-term, and within weeks users develop a tolerance to them. "As larger doses are taken to produce the same effects, women may become irritable, anxious, or overconfident and various physical symptoms may occur including blurred vision, dizziness, and insomnia." Chronic use of amphetamines can result in damage to the heart and blood vessels, irrational outbursts of anger, psychiatric problems, and susceptibility to infections (Carlson, Eisenstat, & Ziporyn, 2004).

Aging appears to produce greater sensitivity to drugs. A dose, for example, that is appropriate for a younger person might be too much in an older person. Many older people take multiple medicines, and when those that depress the Central Nervous System are mixed with tranquilizers or opioids, the effect can be very dangerous and even result in death. Older women, particularly, are often reticent to question the doctor about drug interactions, drug dependency, or addictive potential for fear of seeming to challenge the doctor's authority (Carlson, Eisenstat, and Ziporyn, 2004), so it's a problem doctors need to keep in mind.

Drug Seekers

Certain characteristics are common in persons who are addicted to prescription drugs. One is escalating use. A drug-seeker may exhibit manipulative, demanding behavior in order to obtain a prescription. He or she may claim his only chance of improving is to get a prescription for an addictive substance. A drug-seeker may describe symptoms that are not supported by physical evidence or insist that non-addictive medicines "don't work." He or she may claim to be allergic to non-addictive medicines. The drug-seeker may claim his medicine was lost or stolen or that…