Definitions And Drug Classification

Drug dependence has been defined as a state, psychological and/or physical, resulting from an interaction between a drug and an organism characterised by a compulsion to take the drug on a continuous or periodic basis to experience its psychic effects and/or avoid the discomfort of its absence. Figure 23.1 shows the interactions between a drug and an individual. This definition of dependence (WHO) covers all forms of drug dependence which may be psychological or physical or combinations of both, accompanied or not by tolerance to the drug. Because of these complexities drug dependence is classified somewhat on the basis of the effects produced or nature of the dependence-producing compound. The major groups to be considered are:

Drugs And Brain Function

Figure 23.1 The diagram shows the stages that may occur after administration of a non-medical drug. The details of each of the potential consequences are given in the text but note that whereas all drugs must have some psychological effect and so may trigger psychological dependence, physical dependence is only obvious with depressant drugs

Figure 23.1 The diagram shows the stages that may occur after administration of a non-medical drug. The details of each of the potential consequences are given in the text but note that whereas all drugs must have some psychological effect and so may trigger psychological dependence, physical dependence is only obvious with depressant drugs

Depressants: alcohol, barbiturates Opioids: heroin, morphine, methadone Stimulants: amphetamines, cocaine, Ecstasy Psychedelics: LSD, mescaline, 'magic mushrooms' Inhalants: glue, solvents Cannabis:

Legal definitions of drugs

Class A: cocaine, heroin, LSD, methadone, mescaline, morphine, opium, Ecstasy plus all class B when taken in injectable form amphetamine, cannabis, codeine, barbiturates benzodiazepines

Drugs with no therapeutic use (cannabis, LSD) and so are not prescribed Drugs with medical use — heroin and morphine for pain relief, amphetamine for narcolepsy and cocaine

These can be possessed by doctors, pharmacists and nurses and prescribed

Benzodiazepines which can be possessed by those above and also others as long as they are a medicinal product (use for epilepsy, anxiety and sleeping pills)

Cough medicines, etc. with small amounts of opioids which are non-prescribed, and can be bought over the counter

Class B: Class C:

Schedules: 1

2&3

Acute administration of a drug of abuse will produce acute effects related to that drug. The psychological effects must somehow reinforce the administration of the drug. On repeated use tolerance may develop leading to an increase in the dose of drug required to produce the required effect. Psychological dependence occurs and is defined as 'a condition in which a drug produces a feeling of satisfaction and a psychic drive that requires administration of the drug to produce pleasure or avoid discomfort'. Psychological dependence varies from mild to strong depending on the drug used. Physical dependence is 'an adaptive state that manifests itself by intense physical disturbance when the drug is discontinued'. Physical dependence is not produced by all drugs of abuse and is most pronounced after use of depressant drugs such as alcohol or heroin. If a drug usage is halted withdrawal or abstinence occurs, the symptoms of which can be psychological (i.e. cravings, discomfort, etc.) and/or physical on the basis of whether physical and psychological dependence are present. To avoid withdrawal symptoms drug administration is continued and a cycle is set up (see Table 23.1).

Continue reading here: Drugs Used

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