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Drug addiction, or dependency is the compulsive use of drugs, to the point where the user has no effective choice but to continue use. This phenomenon has occurred to some degree throughout recorded history (see " opium"), though modern agricultural practices, improvements in access to drugs, and advancements in biochemistry have exacerbated the problem significantly in the 20th century with the introduction of purified forms of active biological agents, and with the synthesis of hitherto unknown substances, such as methamphetamine and gamma-hydroxybutyrate (GHB). While "addiction" has been replaced by "dependency" as a clinical term, the terms are used interchangeably here.The addictive nature of drugs varies from substance to substance, and from individual to individual. Drugs such as codeine or alcohol, for instance, typically require many more exposures to addict their users than drugs such as heroin or cocaine. Likewise, a person who is psychologically or genetically predisposed to addiction is much more likely to become dependent.
Drug addiction has two components, physicalAntonym of psychical. The word physical " when used alone, has several possible meanings in the English language. It can refer to the body. It can specify the quality of an object to occupy space. dependency and psychological dependency. Physical dependency occurs when a drug has been used habitually and the body has become accustomed to its effects. The person must then continue to use the drug in order to feel normal, or its absence will trigger the symptoms of withdrawalWhen an addictive behavior is stopped or an addictive substance is withdrawn from use, withdrawal symptoms almost always follow. Depending on the behavior or substance, these symptoms can appear within a few hours ( nicotine) or over a few days or weeks (. Psychological dependency occurs when a drug has been used habitually and the mind has become emotionally reliant its effects, either to elicit pleasure or relieve pain, and does not feel capable of functioning without it. Its absence produces intense cravings, which are often brought on or magnified by stressStress has different meanings in different fields: Stress in physics, see also pressure. Medical or psychological stress, see stress (medicine). Vocal stress, see phonology. Link stress (network theory). Moisture stress or plant stress is the result of de. A dependent person may have either aspects of dependency, but often has both.
1 The basis for addiction
Scientists have long accepted that there is a biologicalBiology studies the variety of life clockwise from top-left E. coli tree fern, gazelle, Goliath beetle Biology is the science of life. It is concerned with the characteristics and behaviors of organisms, how species and individuals come into existence, an basis for drug addiction, though the exact mechanisms responsible are only now being identified. It is believed that addictive substances create dependence in the user by changing the brain's reward functions, located in the mesolimbicThe mesolimbic pathway is one of the neural pathways in the brain which links the ventral tegmentum area in the midbrain to the nucleus accumbens in the limbic system. It is one of the four major pathways where the neurotransmitter dopamine is found. dopamineDopamine is a neurotransmitter in the brain. As a member of the catecholamine family, dopamine is a precursor to epinephrine ( adrenaline) and norepinephrine ( noradrenaline) in the biosynthetic pathways for these neurotransmitters. Dopamine is synthesize system—the part of the brain that reinforces certain behaviors such as eatingEating is the activity of consuming food and its digestion. Among human beings, eating is a central part of home life and many social activities. The preparation and consumption of food also has many cultural components, and plays an important role in all, sexual intercourse, exercise, and social interaction. Addictive substances, through various means and to different degrees, cause the synapses of this system to flood with excessive amounts of dopamine, creating a brief rush of euphoria more commonly called a "high".
Although the high may last only a few minutes, it also produces more longer-lasting effects in the brain. Dopamine signals occurring normally in the reward system (traveling from the ventral tegmental area to the nucleus accumbens) lead to the activation of proteins designed to calm the initial reaction and foster a continued desire to pursue the behavior responsible. Addictive substances create a greater than normal dopamine release, and the subsequent reactions of the brain are greatly exaggerated as well. The amygdala, hippocampus, and frontal cortex associate the use of the drug with intense pleasure and well-being; an association that is strengthened with each exposure, and which over time comes to dominate normal thoughts and desires. When cravings for the drug are no longer controllable, the user is considered addicted.
