What is Drug abuse (Substance abuse)

Drug abuse and dependence is a psychological disease.

Statistics on Drug abuse (Substance abuse)

In 1997, 4.9% of Australians aged 18-34 suffered from a drug use disorder. In 2001, 37.7% of the Australian population over the age of 14 years had ever used an illicit drug.

The incidence of drug use varies between nations and socioeconomic groups. Certain drugs are also more accessible in certain regions, increasing the likelihood of substance abuse.

Risk Factors for Drug abuse (Substance abuse)

There is no single cause of drug misuse and/or dependence, although 3 factors appear commonly:

  1. the availability of drugs;
  2. a vulnerable personality; and
  3. social pressures, particularly from peers.

Progression of Drug abuse (Substance abuse)


1% of adolescents in the UK sniff solvents for their intoxicating effect. Tolerance develops over weeks to months. Intoxication is characterised by euphoria, excitement, a floating sensation, dizziness, slurred speech and ataxia. Acute intoxication can cause amnesia and visual hallucinations.

Amphetamines and related substances

These have temporary stimulant and euphoriant effects that are followed by fatigue and depression. Depression can prolong for weeks. Psychological rather than true physical dependence is the rule with speed. In addition to a manic-like presentation, amphetamines can produce a paranoid psychosis indistinguishable from acute paranoid schizophrenia.


Ecstasy (MDMA) is a psychodelic drug with a brief duration of action (4-6 hours). There is evidence that repeated use of MDMA can cause permanent neurotransmitter changes in the brain. Deaths have been reported from malignant hyperprexia and dehydration. Acute renal and liver failure can occur.


Cocaine is a central nervous system stimulant. This causes an intense stimulating effect and “free-basing” is common. Free-basing involves the smoking of cocaine. Compulsive use and dependence occur more frequently among users who are free-basing.

Dependent users take large doses and alternate between the withdrawal phenomena of depression, tremor and muscle pains, and the hyperarousal produced by increasing doses. Prolonged use of high doses produces irritability, restlessness, paranoid ideation and occasionally convulsions. Persistent sniffing of the drug can cause perforation of the nasal septum. Overdoses cause death through myocardial infarction, hyperthermia and arrhythmias.


LSD produces distortions and intensifications of sensory perceptions, as well as hallucinations in acute intoxification. Psychosis is a long-term complication.


Cannabis when smoked, exaggerates the pre-existing mood, be it depression, euphoria or anxiety. It may have specific analgesic properties. It can cause tolerance and dependence. An amotivational syndrome has been reported with chronic daily use.


Drugs causing dependence include barbituates and benzodiazepines. Benzodiazepine dependence is common especially when the drugs are prescribed and not discontinued. Discontinuing treatment with benzodiazepines may cause withdrawal symptoms and so should be supervised and gradual.


Physical dependence occurs with morphine, heroin and codeine as well as with synthetic and semisynthetic opiates such as methadone and pethidine. The withdrawal effects of one are reduced by administration of one of the others. The psychological effect of such substances is of a calm, slightly euphoric mood associated with freedom from physical discomfort and a flattening of emotional response. Opiate addicts have a relatively high mortality rate, owing to both the ease of accidental overdose and the blood-borne infections associated with shared needles. Heart disease (including infective endocarditis), tuberculosis and AIDS are common causes of death, while tetanus and the complications of hepatitis B and C are common.

How is Drug abuse (Substance abuse) Diagnosed?

Toxicology screens (drug testing) done on blood and urine specimens can reveal the existence of a wide variety of chemicals and drugs in the body. The sensitivity depends upon the substance itself, when the substance was taken, and the testing laboratory. Blood tests are more likely to detect the presence of an abused substance than urine tests, however, urine drug screens are more frequently done.

Opiates and narcotics are usually present in the urine 12 to 36 hours after the last use, depending on the amount used and the frequency.

CNS stimulants, such as cocaine, can be detected in urine anywhere between 1 to 12 days, again dependent upon the frequency of use.

CNS depressants such as Valium and Xanax are detected up to 7 days after the last day of use, mostly depending on the substance used and how quickly it is eliminated by the body (half-life).

Most hallucinogens are also detectable in the urine up to 7 days after the last use. However, cannabis can be detected up to 28 days in regular users.

Prognosis of Drug abuse (Substance abuse)

Drug abuse and dependence can potentially lead to a fatal drug overdose. Relapses from drug abstinence may occur and lead to recurrent dependence.


  • Depression
  • Relapse of drug abuse
  • Drug overdose
  • Bacterial endocarditis, hepatitis, thrombophlebitis, pulmonary emboli, malnutrition, or respiratory infections, caused by intravenous drug abuse.
  • Infection with AIDS through shared needles.
  • Disinhibition may lead to unsafe sexual practices which may result in unwanted pregnancies, sexually transmitted infections, HIV or hepatitis.
  • Problems with the law.
  • Increase in various cancer rates: lung and pharynx are associated with nicotine use, mouth and stomach cancer are associated with alcohol abuse and dependence for example.
  • Problems with memory and concentration are seen with hallucinogen use, including marijuana (THC).

How is Drug abuse (Substance abuse) Treated?

The treatment of chronic dependence is directed towards helping the patient to live without drugs. Patients need help and advice in order to avoid a withdrawal syndrome. Alternatively, patients can be helped to minimise harm to themselves and others.

Drug abuse (Substance abuse) References

  1. Australian Institute of Health and Welfare. Statistics on Drug Use in Australia 2002.
  2. Kumar P, Clark M. Clinical Medicine. Fourth Ed. WB Saunders, 2002.
  3. MEDLINE Plus.

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