According to the 2016 statistics, 43% of Australians have used illicit drugs once in their lifetime.

  • 15.6% used recently
  • 8.6% used within the last month
  • 5.6% used within the last week

Only a small proportion of people who ever try drugs become frequent users
13.4% risk (Anthony et al. 1994)
Rule of thumb: 20% risk

Waste Water Analysis

Self-reported statistics are only partially valid, as people can submit false results. A waste water analysis in Adelaide showed that Methamphetamine was the most prevalent drug used, despite the statistics saying that MDMA was the most used.

Prevalence By Age

  • 9% of users 14-19
  • 32% of users are aged 20-29
  • 11.5% of users are aged 50-59
  • 10.9% of users are aged 60+

Australia has an aging population of illicit drug users

Adolescent Onset: Alcohol

  • Age of first use: 17.3

Peak consumers are 70+ years.

The number of daily users has been decreasing since 2004.

Adolescent Onset: Tobacco

  • Age of first use: 16.3

Demographic Risk Factors

Family

i.e. association with drug-using peer groups.
Parents, siblings, past criminality, extreme poverty, broken families, abuse, low parent-child attachment, commitments to school

Sibling

  • Risk increases when the relative age between siblings is 0-4
  • Stable until a difference of 10

Vygotsky - Zone of proximal development

  • Risk increases when siblings are of the same gender
  • Risk increases when the drug dependent sibling is older
  • Shared experiences of a common risky environment

Community

Drug availability, neighbourhood, community prevalence

Society

Levels of law enforcement, tax, price, regulation

Drug Expectancy

Risk factors function to increase positive drug expectancies and decrease negative expectancies (Leventhal, 2006)

  • Transmission of parental beliefs (demographic risk factor)

Early Onset

  • Probability of dependency increases with duration of use
  • Probability of dependency increases with earlier age
  • Probability of dependency increases with parental beliefs and support

Drug Liking

  • Probability of dependency increases with liking of the initial experience

Note: Positive correlation is not causation.

Correlation: Ice cream on a hot day.
Ice cream sales do not cause hot weather. Hot weather does not cause ice cream sales.

Accuracy of Statistics

Addicts may have conflated experiences - believing that their initial experience was better than it was at the time.

Fergusson's cannabis model queried the users at an earlier time after their initial use.

A follow up (2 years after) revealed that:

  • 12.4% of those who said that they did not get high during the initial experience, became dependent
  • 34.1% of those who said that they did not get really high in early experiences, became dependent
  • Negative experiences did not modify the risk of later dependence

Development Trajectories of Smoking

  • Early Stable Smoking - Associated with parents and peers who smoked
    • Frequency ceiling is higher than late stable smokers
  • Late stable
  • Quitter
  • Experimenter

Chippers

People who maintain a low level of drug users over a period of time, but are not dependent.

i.e. people who take a prescribed ritual (i.e. only doing drugs at raves, only one a night)

Life History (study of 10 opiate addicts)

  • Bouts of use followed by abstinence then relapse then abstinence, etc
  • Addiction is a chronically relapsing disorder

Gateway Hypothesis

The idea that experimentation precedes the use of marijuana, pills, snorting, injecting

  • Different drugs might compliment one another - smoking and alcohol
  • A drug may be used to counteract the withdrawal phase of another drug
  • Substitution when the primary drug is unavailable
  • Cross-sensitisation - enhance senses and brain reward systems
  • 'Common syndrome' - "try the others"

Drug Exit

Natural Recovery

80% - largely undertaken by individuals 30-40 years old, who have used drugs for 5-15 years (Sobell et al 2000, Price et al 2001)

Exit Treatments

  • Availability and Acceptability
  • Legal Referral from Courts or Criminal Sanctions
  • Prior experience of treatment

Treatment seekers are also characterised by a higher incidence of psychiatric symptoms

Cigarette Usage

Whilst most other drugs decease in usage over time, smoking remains stable.