Drug Profile Drug addiction is a human issue that cultivates biological, psychological, and social consequences, among others. The manifestation of addiction itself is characterized by physical dependence, and is defined by the uncontrollable, compulsive urge to seek and use drugs despite harmful repercussions (Fernandez, Rodriguez & Villa, 2011). Philologically, drug use affects the reward center, where dopamine receptors are over-stimulated. Ultimately, the repetition of drug use is encouraged to achieve the same, heightened, pleasure response (U.S. DHHS, 2007). Psychological responses to drug use may reflect motivations caused by positive pleasure, anxiety, or protection. The bodily effects of drugs often reflect the drug's class: stimulants, depressants, narcotics, hallucinogen, and cannabis. Each class represents various drugs and causes distinct biochemical responses. In addition to illicit drugs, prescription drugs are also highly abused and are categorized within the drug classes. Drug addiction does not discriminate between gender, race, sexual orientation or creed, and its psychological and physiological effects mirror the drug's inherent properties.

To understand the physiology of drug addiction, one must first recognize that all drugs are chemical compounds. Each drug is composed of various chemical properties that react to receptors within the brain, stimulate biochemical processes, and the individual then experiences the consequent biophysical outcomes. Areas of the brain that are affected by drug use include the brain stem, the cerebral cortex, and the limbic system. The brain stem controls basic processes that are vital to sustaining life, such as breathing, heart rate, and sleeping (U.S. DHHS, 2007). The cerebral cortex interprets information received from senses, controlling the ability to see, feel, hear, and taste. The front part of the cerebral cortex, the frontal cortex, is responsible for the ability to think, make decisions, and solve problems (U.S. DHHS, 2007). The limbic system is responsible for perpetuating addiction, as this system contains the brain's reward circuit. Various brain structures within the limbic system regulate and dictate one's ability to feel pleasure (U.S. DHHS, 2007). Feeling pleasure is a motivation to participate in actions necessary to sustain life, such as eating. By consuming drugs, however, one also initiates the reward system, which gives pleasure, and then one can perceive this pleasure as motivation to continue using drugs.

The limbic system functions in a way to ensure that human beings repeat actions that are vital to sustaining life "by associating those actions with pleasure or reward" (U.S. DHHS, 2007, p. 18). When drugs are used, the limbic system encourages drug use to be repeated in order to elicit the same pleasure response. The biophysical rewards experienced by drug use are the result of dopamine, a neurotransmitter, being released in the brain. It is widely supported by researchers that the dopaminergic system, located in the ventral tegmental area which connects the midbrain to the nucleus accumbens and other forebrain sites, is the main substrate of reward and pleasure for both natural rewards and addictive drugs (Hyman & Malenka, 2001). The release of dopamine is triggered by drugs, which then transmits the pleasure response. The brain then signals for the pleasure response to be repeated, and drug use is needed again to achieve the same intensity of dopamine transmission.

The psychology of drug addiction is driven by dependence. Psychological dependence occurs when an individual feels that a drug is essential to sustain their comfort or well-being (Coon & Mitterer, 2009). An individual who is under the influence of psychological dependence typically experiences intense cravings for the drug and its associated rewarding qualities. The perceived rewarding qualities of any drug are dictated by their class. For example, if an individual uses a stimulant such as cocaine, the psychological reward is coupled with the feeling of euphoria, well-being, and high energy (Coon & Mitterer, 2009). If an individual uses a depressant, such as alcohol, the psychological effects are conducive of relaxation and satisfaction. Some individuals experience psychological dependence as a way to cope with anxiety, or to protect themselves against a personal issue that the individual feels they cannot process in a natural way (Coon & Mitterer, 2009).

Every drug, illicit or otherwise, is categorized into a drug class that indicates the overall behavior of the substance. Five of the major drug classes are: stimulants, depressants, narcotics, hallucinogens, and cannabis. Stimulants, also known as "uppers," improve mental and physical function by reversing the effects of fatigue (Joseph, 2005). Caffeine and nicotine are two commonly used stimulants, and are known for their ability to increase alertness. Cocaine and amphetamines are two additional stimulant drugs. After the effects of a stimulant begin to wane, the user enters into a dysphoric crash, and frequent, repeated doses of the drug are needed to avoid intense fatigue and depression associated with "coming down" (Joseph, 2005, p. 38). Nicotine is known for its high addictive potential. Cocaine and amphetamines are also recognized for their significant physical dependence. Withdrawal from stimulants includes disorientation, irritability, apathy, and long periods of sleep (CDMHAS).

Depressants...

Depressants are known as "downers," and include sedatives, hypnotics, tranquilizers, and anti-anxiety medications. One of the most accessible depressants is alcohol and is identified as having a high level of physical dependence (CDMHAS). Depressants also include barbiturates, which have a moderate to high addictive potential, and benzodiazepines, which have a low level of physical dependence (CDMHAS). Withdrawal from depressants includes anxiety, convulsions, insomnia, tremors, and possible death (CDMHAS).
The term "narcotic," is derived from the Greek word for stupor, and refers to drugs that create morphine-like effects (Joseph, 2005). In legal context, the term "narcotic" refers to drugs derived from opium that bind at opiate receptors. Examples of narcotics include heroin, morphine, codeine, oxycodone, and hydrocodone (Joseph, 2005). Heroin, morphine, hydrocodone, and oxycodone are recognized as having high addictive potential, and codeine is considered to have a moderate addictive potential (CDMHAS). Withdrawal from narcotics includes such symptoms as nausea, chills, sweating, irritability, loss of appetite, and panic (CDMHAS). Hallucinogens are known for their ability to alter human perception and mood, and include such drugs as LSD, ecstasy (MDMA), mescaline and peyote, ketamine and PCP (Joseph, 2005). LSD, mescaline and peyote, are considered to have no development of physical dependence and withdrawal symptoms are unknown (CDMHAS).

Three drugs that are derived from cannabis are marijuana, hashish, and hashish oil. Marijuana is the most frequently used illegal drug worldwide, and is the preferred cannabis drug due to its high content of delta-9-tetrahydrocannabinol (THC) (Joseph, 2005). THC is understood to be responsible for the majority of the psychoactive effects that are indicative of cannabis drugs. The effects of cannabis use depend on the drug's form and activity of drug, and effects range from a sense of well-being and relaxation to alterations in thought formation and expression (Joseph, 2005). The physical dependence potential of marijuana and cannabis drugs is unknown (CDMHAS). Cannabis users, like all drug users, can experience psychological dependence.

Advances in biomedical development and manufacturing have led to the increased availability of prescription drugs that treat pain, anxiety, mental disorders, and other conditions (U.S. DHHS, 2006). Many prescription medications exhibit psychoactive effects, such as opium derivatives for pain treatment, benzodiazepines for anxiety and panic disorders, barbiturates for insomnia, anxiety, and seizure control, and stimulants for treatment of ADD and ADHD (U.S. DHHS, 2006). Each of these types of prescription medications represents a potential for misuse, abuse, and addiction. Especially with older adults, as persons over the age of 65 represent only 13% of the population, but are responsible for "one-third of all medications prescribed" (U.S. DHHS, 2006, p.1). The availability and increased access of prescription drugs have also increased the potential for these drugs to be abused, and their users to become addicted.

Drug addiction affects an individual both physiologically and psychologically, and one's responses will reflect a drug's intrinsic properties. Physiologically, drug use affects three areas of the brain: the brain stem, the cerebral cortex, and the limbic system. Of these, the limbic system perpetuates addiction as it controls the pleasure and reward process. Drug use induces the release of dopamine, a neurotransmitter, which stimulates the area of the brain that reinforces life-sustaining actions with a pleasure response (U.S. DHHS, 2007). The brain functions so pleasure-inducing actions are encouraged to be repeated, therefore, an individual is motivated to use drugs over and over to elicit the same pleasure response. The psychology of addiction is dictated by psychological dependence. Psychological dependence occurs when an individual feels a drug is necessary to sustain well-being, or is driven by a need to cope with anxiety or to protect themselves from personal issues they feel they cannot solve.

Each drug is identified within a class which distinguishes the drug's inherent behavior. Stimulants are known for increasing alertness, physical and mental performance, and include such addictive drugs as nicotine, cocaine, and amphetamines. Alcohol, barbiturates, and benzodiazepines are depressants, and are known for depressing brain functions to induce relaxation and to relieve anxiety. Narcotics refer to opium derivates, such as morphine, heroin, oxycodone, and hydrocodone. Hallucinogens alter mood…