Epidemiology of addictive disorders: a brief review

MRCPsych addiction psychiatry seminar series

Dr Stuart McLaren

2nd March 2012

consumption/use

dependence

problems/harms

Epidemiology of substance use

Prevalence of psychiatric disorders, % adult population

Common mental disorders 16.2

Psychosis 0.4

Alcohol dependence 5.9

Drug 9.2

APMS 2007

Lifetime prevalence of drug use, % of adult population

Overall 35.5

Cannabis 30

Amphetamines 12

Cocaine 7.7

Ecstasy 7.3

Opiates <1

2006/2007 BCS

Prevalence rate of heroin and crack cocaine users in England per 1000 population aged 15 to 64 by gender

Rate 95% CI

Male 15.32 14.86-15.87

Female 4.64 4.61-4.99

Hay et al. 2007

Prevalence of drug dependence, % adult population

All 3.4Cannabis only 2.5Other drugs 0.9

2007 APMS

Prevalence of injecting in England per 1000 population aged 15 to 64

Rate 95% CI

3.01 2.92-3.14

2009/10 NDEC

Main drug in adult treatment populations (n=174250)

Heroin 66%

Crack 6%

Cocaine 6%

Methadone 8%

Cannabis 7% NDTMS 2007/8

Illicit drug trends

• Drug dependence stable since 2000

• Increasing multiple drug use

• Opiate use stable, may be falling in young

• Use of opiates correlates with deprivation

• Cannabis use may be falling

• Use greater in lower income groups

Psychiatric co-morbidity

70% of opiate users have another current psychiatric disorder

Drug dependency strongly associated with:• ASPD• BPD

2007 APMS

Substance related harms and risks

‘with drugs nothing is always. Their use does not carry a guarantee of danger, but neither is their safety guaranteed. What one needs to ask about any substance is not whether in absolute terms it is safe, but rather the degree of risk which may attach to its use.’

Health consequences of drug use

• Acute toxic effects, including overdose

• Acute intoxication effects, including accidental injury and violence

• Dependence

• Adverse health effects of chronic, regular use, including chronic disease, BBVs and mental disorder

Risky periods for opiate users

Risk increases during periods of transition:

• Release form prison (SMR ~8)

• Early in substitute treatment (x3 increase compared with later treatment)

• Following discharge from methadone maintenance treatment (MRR ~10 in first 2 weeks)

consumption/use

dependence

problems/harms

Epidemiology of drinking and alcohol-related harm

Consumption and risk – units/week

Men Women

Low risk <21 <14

Hazardous 22-50 15-35

drinking

Harmful drinking >50 >35

Prevalence of hazardous and harmful drinking, % adult population

hazardous harmfulAUDIT score 8 or more 16 or more

M 38 6

F 15 2

All 25 3.8APMS 2007

Prevalence of alcohol dependence in last 6/12 - % of adult population

M F All

Mild 7.8 3.2 5.4

Moderate 0.8 0 0.4

Severe 0.1 0 0.1

Overall 8.7 3.3 5.9

2007 APMS

Psychiatric co-morbidity

37% of those with alcohol use disorders have another mental disorder

Alcohol dependence is• strongly associated with ASPD• moderately associated with BPD and drug

dependence 2007 APMS

Alcohol trends

• CAGE scores increasing between generations of men

• Dependence and hazardous drinking peak in middle occupations

• Heavy drinking shows no clear class gradient

• Younger people and women at particular risk

1. Risk factors for drug use• Social factors

– Availability

– Early use of tobacco and alcohol

– Disadvantaged background

• Family factors

– Poor parent-child relationships

– Parental conflict

– Parental dug use

2. Risk factors for drug use

Individual factors:

• male

• novelty seeking personality

• early conduct disorder

• poor school performance/early school leaving

Affiliation with antisocial and drug-using peers

Above factors often co-occur

Risk factors for drug dependency

• Early onset of drug use

• Multiple drug use

• Mental health disorders before the age of 15 years (conduct disorder and depression)

Addiction careers

‘the period in which substance use causes problems’

Lifetime use (%) Lifetime dependence (%)

Capture rate

Tobacco 76 24 32

Heroin 1.5 0.4 24

Alcohol 92 14 15

Clinical course of alcohol dependence

Age of:

• First drink* 13-15 years

• First intoxication* 15-17 years

• First problem* 16-22 years

• Onset of dependence 25-40 years

• Age of death 60 years

* Same as general population