The term ''drug abuse'' refers to the use of any drug in a manner which is at variance with the approved use in that particular culture. Thus the term refers to socially disapproved use and is not descriptive of a particular pattern of abuse. For example, chewing the leaves of Catha edulis, or khat, is socially acceptable in the Yemen and other Middle Eastern countries, where there is little evidence that, within the confines of that culture, it is abused or that it causes major health problems. In most European countries, however, its use is illegal and it is treated as a criminal offence to be in possession of this substance. Conversely, alcohol is a major health hazard in most
Fundamentals of Psychopharmacology. Third Edition. By Brian E. Leonard 2003 John Wiley & Sons, Ltd. ISBN 0 471 52178 7
Table 15.1. Drugs of abuse and how their effects may be treated
Mechanism Main neuro-
involved transmitter affected Potential treatment
Action on endogenous receptors for endogenous ligands
Opioids Endorphins, Partial agonists (e.g. buprenorphine)
enkephalins Antagonists (e.g. naltrexone)
Alcohol GABA, endorphins Partial agonists (e.g. bretazenil)
Opiate antagonists (e.g. naltrexone) Benzodiazepines GABA Partial agonists (e.g. bretazenil)
Antagonists (e.g. flumazenil) Nicotine Acetylcholine Antagonists (? mecamylamine)
Cannabinoids ? Anandamide Antagonists (e.g. SR141716A)
LSD and related 5-HT 5-HT2 receptor antagonists hallucinogens (e.g. ritanserin)
Increasing the release of endogenous neurotransmitters
Cocaine Dopamine D2 receptor antagonist*
Antagonist of the uptake site (e.g. SSRI)
Solvents ? Noradrenaline ? Receptor antagonists
Antagonizing the action of natural transmitters
Alcohol Glutamate NMDA antagonists (e.g. dizocilpine)
Barbiturates Glutamate AMPA antagonists
(e.g. 2,3-benzodiazepines such as GYKI52466) and some dihydro-quirioxalines such as CNQX)
*Most typical (e.g. haloperidol) and atypical (e.g. sulpiride, tiapride, risperidone) neuroleptics have a high affinity for D2 receptors.
industrialized countries where it is socially accepted, but is banned in many Muslim countries, with dire consequences for those transgressing the ban.
''Non-medical drug use'' covers, for example, the occasional use of alcohol and the regular use of the opioid analgesics. This term includes the occasional recreational use of licit and illicit drugs for their pleasurable effects (e.g. the use of amphetamines or cannabis) and outside their approved medical indications.
''Drug dependence'' is defined as a syndrome in which someone continues to take the drug because of the reinforcing effect which is derived from it. This behaviour occurs despite the adverse social or medical consequences which it may have; the dependent person is motivated to continue taking the drug for his/her continued well-being. Often the dose of the drug must be increased to maintain its desired effect. This leads to a change in the behaviour of the dependent person, which varies from a mild desire to obtain the drug to a craving or compulsion. With some drugs of abuse, for example the opioids, physical and psychological dependence on the drug may occur so that lifestyle becomes dominated by the need to secure further supplies of the drug.
The term ''addiction'' is so non-specific that it should no longer be used. When used, it suggests that the person is severely dependent on a drug of abuse.
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