Addiction

Psychoactive drugs are often associated with addiction or drug dependence. Dependence can be divided into two types: psychological dependence, by which a user experiences negative psychological or emotional withdrawal symptoms (e.g., depression) and physical dependence, by which a user must use a drug to avoid physically uncomfortable or even medically harmful physical withdrawal symptoms. Physical dependence on antidepressants or anxiolytics may result in worse depression or anxiety, respectively, as withdrawal symptoms. Unfortunately, because clinical depression (also called major depressive disorder) is often referred to simply as depression, antidepressants are often requested by and prescribed for patients who are depressed, but not clinically depressed. Drugs that are both rewarding and reinforcing are addictive; these properties of a drug are mediated through activation of the mesolimbic dopamine pathway, particularly the nucleus accumbens. Not all addictive drugs are associated with physical dependence, e.g., amphetamine, and not all drugs that produce physical dependence are addictive drugs, e.g., caffeine.

Many professionals, self-help groups, and businesses specialize in drug rehabilitation, with varying degrees of success, and many parents attempt to influence the actions and choices of their children regarding psychoactives.

Common forms of rehabilitation include psychotherapy, support groups and pharmacotherapy, which uses psychoactive substances to reduce cravings and physiological withdrawal symptoms while a user is going through detox. Methadone, itself an opioid and a psychoactive substance, is a common treatment for heroin addiction, as is another opioid, buprenorphine. Recent research on addiction has shown some promise in using psychedelics such as ibogaine to treat and even cure drug addictions, although this has yet to become a widely accepted practice.

Usage

Psychoactive substances are used by humans for a number of different purposes to achieve a specific goal. These uses vary widely between cultures. Some substances may have controlled or illegal uses while others may have shamanic purposes, and still others are used medicinally. Other examples would be social drinking or sleep aids. Caffeine is the world's most widely consumed psychoactive substance, but unlike many others, it is legal and unregulated in nearly all jurisdictions. Psychoactive drugs are divided into different groups according to their pharmacological effects. Commonly used psychoactive drugs and groups:

· Anxiolytics

Example: Benzodiazepine

· Euphoriants

Example: MDMA (Ecstasy), MDA, 6-APB, Indopan

· Stimulants ("uppers"). This category comprises substances that wake one up, stimulate the mind, and may even cause euphoria, but do not affect perception.

Examples: amphetamine, caffeine, cocaine, nicotine

· Depressants ("downers"), including sedatives, hypnotics, and narcotics. This category includes all of the calmative, sleep-inducing, anxiety-reducing, anesthetizing substances, which sometimes induce perceptual changes, such as dream images, and also often evoke feelings of euphoria.

Examples: ethanol (alcoholic beverages), opioids, barbiturates, benzodiazepines.

· Hallucinogens, including psychedelics, dissociatives and deliriants. This category encompasses all those substances that produce distinct alterations in perception, sensation of space and time, and emotional states

Examples: psilocybin, LSD, Salvia divinorum and nitrous oxide.

Ritual and spiritual

Certain psychoactives, particularly hallucinogens, have been used for religious purposes since prehistoric times. Native Americans have used peyote cacti containing mescaline for religious ceremonies for as long as 5700 years. The muscimol-containing Amanita muscaria mushroom was used for ritual purposes throughout prehistoric Europe. Various other hallucinogens, including jimsonweed, psilocybin mushrooms, and cannabis, have been used in religious ceremonies for millennia.

In the United States, the use of peyote for ritual purposes is protected only for members of the Native American Church, which is allowed to cultivate and distribute peyote. However, the genuine religious use of peyote, regardless of one's personal ancestry, is protected in Colorado, Arizona, New Mexico, Nevada, and Oregon.

Recreation

Many psychoactive substances are used for their mood and perception altering effects, including those with accepted uses in medicine and psychiatry. The following substances, all widely illegal unless stated otherwise, are here listed by order of world-wide popularity:

· alcohol –In most areas of the world it is legal for those over a certain age. It is an IARC 'Group 1' carcinogen and a teratogen.

· tobacco – A legal drug, containing nicotine, which crosses the blood–brain barrier in 10–20 seconds. It mimics the action of the neurotransmitter acetylcholine at nicotinic acetylcholine receptors in the brain and theneuromuscular junction. The neuronal forms of the receptor are present both post-synaptically (involved in classicalneurotransmission) and pre-synaptically, where they can influence the release of multiple neurotransmitters.

· cannabis – Contains at least 85 cannabinoids. The primary psychoactive component is THC (tetrahydrocannabinol), which mimics the neurotransmitter anandamide, named after the Hindu ananda, "joy, bliss, delight." The review article Campbell & Gowran (2007) states that "manipulation of the cannabinoid system offers the potential to upregulate neuroprotective mechanisms while dampening neuroinflammation. Whether these properties will be beneficial in the treatment of Alzheimer's disease in the future is an exciting topic that undoubtedly warrants further investigation."

· caffeine - A legal drug, contained in coffee, tea, energy drinks, and some soft drinks.

· MDMA - The "euphoriant drugs such as MDMA (‘ecstasy’) and MDEA (‘eve’)" are popular amongst young adults.MDMA "users experience short-term feelings of euphoria, rushes of energy and increased tactility."

· cocaine – When transformed into its freebase form, crack, the cocaine vapour may be inhaled directly. This is thought to increase bioavailability, but has also been found to be toxic, due to the production of methylecgonidine duringpyrolysis.

· amphetamines – Prescribed for ADHD. A potent central nervous system stimulant, increases muscle strength and fatigue resistance and improves reaction time. Unlike amphetamine, methamphetamine is neurotoxic, damaging dopamine neurons. As a result of this brain damage, chronic use can lead to post acute withdrawal syndrome.

· psilocybin mushrooms – Until 1963, when it was chemically analysed by Albert Hofmann, it was completely unknown to modern science that psilocybe semilanceata ('Liberty Cap', common throughout Europe) contains psilocybin, a hallucinogen previously identified only in species native to Mexico, Asia and North America.

· LSD – A popular ergoline derivative, that was first synthesized in 1938 by Hofmann. However, he failed to notice its psychedelic potential until 1943. In the 1950s, it was used in psychological therapy and played a central role in 1960s 'counter-culture', and was banned in October 1968 by US President Lyndon B Johnson.

· opiates and opioids – Available by prescription. This "drug derived from the unripe seed-pods of the opium poppy... produces drowsiness and euphoria and reduces pain. Morphine and codeine are opium derivatives."

· tranquilizers – barbiturates, benzodiazepines (commonly prescribed for anxiety; known to cause dementia and post acute withdrawal syndrome)

· nitrous oxide - legal

· ketamine – used by paramedics in emergency situations for its dissociative and analgesic qualities

· 'mystery white powders' – (street drug labelling and composition can be unclear)

· amyl nitrite – a vasodilator (legal)

· Drugs (antidepressants, tranquilizers, analgesics, etc)

Anesthesia

General anesthetics are a class of psychoactive drug used to block physical pain and other sensations. Most anesthetics induce unconsciousness, allowing the person to undergo medical procedures like surgery without the feelings of physical pain or emotional trauma. To induce unconsciousness, anesthetics affect the GABA and NMDA systems. For example, halothane is a GABA agonist, and ketamine is an NMDA receptor antagonist.

Pain management

Psychoactive drugs are often prescribed to manage pain. The subjective experience of pain is primarily regulated by endogenous opioid peptides. Thus, pain can often be managed using psychoactives that operate on this neurotransmitter system, also known as opioid receptor agonists. This class of drugs can be highly addictive, and includes opiate narcotics, like morphine and codeine. NSAIDs, such as aspirin and ibuprofen, are also analgesics. These agents also reduce eicosanoid-mediated inflammation by inhibiting the enzyme cyclooxygenase.

Mental disorders

Psychiatric medications are psychoactive drugs prescribed for the management of mental and emotional disorders, or to aid in overcoming challenging behavior. A psychiatric medication is a licensed psychoactive drug taken to exert an effect on the chemical makeup of the brain and nervous system. Thus, these medications are used to treat mental disorders. Usually prescribed in psychiatric settings, these medications are typically made ofsynthetic chemical compounds, although some are naturally occurring, or at least naturally derived. Since the mid-20th century, such medications have been leading treatments for a broad range of mental disorders and have decreased the need for long-term hospitalization therefore lowering the cost of mental health care. There are six major classes of psychiatric medications:

· Antidepressants, treat disparate disorders such as clinical depression, dysthymia, anxiety, eating disorders and borderline personality disorder.

· Stimulants, which are used to treat disorders such as attention deficit disorder and narcolepsy and to suppress the appetite.

· Antipsychotics, which are used to treat psychotic symptoms, such as those associated with schizophrenia or severe mania.

· Mood stabilizers, which are used to treat bipolar disorder and schizoaffective disorder.

· Anxiolytics, which are used to treat anxiety disorders.

· Depressants, which are used as hypnotics, sedatives, and anesthetics, depending upon dosage.

In addition, several psychoactive substances are currently employed to treat various addictions. These include acamprosate or naltrexone in the treatment of alcoholism, or methadone or buprenorphine maintenance therapy in the case of opioid addiction.

Psychiatric medications carry risk for adverse effects. The occurrence of adverse effects can potentially reduce drug compliance. Some adverse effects can be treated symptomatically by using adjunct medications such as anticholinergics (antimuscarinics). Some rebound or withdrawal adverse effects, including the possibility of a sudden or severe emergence or re-emergence of psychosis, may appear when the drugs are discontinued, or discontinued too rapidly.

Дата добавления: 2015-07-12