marijuana use disorders in the united states: 1991-1992 and 2001-2002

Marijuana Use Disorders in the United States:

1991-1992 and 2001-2002

Wilson M. Compton, M.D., M.P.E.Director, Division of Epidemiology, Services and Prevention Research

National Institute on Drug AbuseDepartment of Health and Human Services

May 5, 2004American Psychiatric Association Annual Meeting

Background

A great deal of information about trends in use of drugs is available, but no data provides reliable and valid measures of drug disorders over the past decade.

Background

With data from two large household surveys of the U.S. adult population, this study seeks to answer the following questions:

1. What are the rates of marijuana abuse and dependence in 1991-1992 compared to 2001-2002?

2. Have the relationships of age, race/ethnicity or gender to marijuana abuse and dependence changed during this period?

Methods

Studies:

• Large studies of the U.S. non-institutionalized household adult (18+) population conducted by the Census Bureau.

• NLAES: National Longitudinal Alcohol Epidemiologic Study (N = 42,862)

• NESARC: National Epidemiologic Study of Alcohol and Related Conditions (N = 43,093)

Methods

Interview:

• AUDADIS: Alcohol Use Disorder and Related Disabilities Interview Schedule - DSM-IV Version

– Specific measures of each criterion of abuse and dependence on marijuana

– Reliability and validity well-established

Methods

Outcomes

• Marijuana use, abuse and dependence in overall population and by age, race/ethnicity and sex

• Marijuana abuse and dependence among marijuana users by age, race/ethnicity and sex

Results: Total Population

4.01.2

30.2

4.11.5

35.6

05

10152025303540

Use Abuse/Dependence Abuse/Dependencein Users

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Total PopulationComparing 1991-1992 to 2001-2002:

• Marijuana use rates were virtually the same: 4.0% versus 4.1%

• Marijuana abuse or dependence increased from 1.2% to 1.5% (p = .014)

• Marijuana abuse or dependence among users increased from 30.2% to 35.6% (p < .01)

How consistent are these results across age groups, race/ethnic groups and sexes?

Results: Marijuana Use by Sex and Race/Ethnicity

0

1

2

3

4

5

6

Black White Hispanic Male Female

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Use In Age Groups

0

2

4

6

8

10

12

Total 18-29 30-44 45-64

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Use in Whites

0

2

4

6

8

10

12

Total 18-29 30-44 45-64

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Marijuana Use in Blacks

0

2

4

6

8

10

12

Total 18-29 30-44 45-64

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Marijuana Use in Hispanics

0

1

2

3

4

5

6

7

8

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Use in Men

0

2

4

6

8

10

12

14

Total 18-29 30-44 45-64

NLAES NESARC

= p < .05

%

Results: Marijuana Use in Women

0

1

2

3

4

5

6

7

8

Total 18-29 30-44 45-64

NLAES NESARC

= p < .05

%

• Use increased significantly for:

– White males 45-64 years old

– Black females overall and Black females 18-29 and 46-64 years old

– Hispanic females 18-29 years old

Results: Marijuana Use in Detailed Age-Sex-Race/Ethnicity Categories

• Rates did not change significantly overall

• Rates increased significantly for:

– 18-29 and 45-64 year olds

– Black and Hispanic 18-29 year olds

– White and Black 45-64 years olds

– Women 18-29 years old and both men and women 45-64 years old

– Selected age-sex-race/ethnicity categories

Results: Summary of Marijuana Use

Results: Marijuana Abuse or Dependence in Overall Population

0.00.51.01.52.02.53.03.54.04.5

Total 18-29 30-44 45-64

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Abuse or Dependence by Sex and Race/Ethnicity

0.0

0.5

1.0

1.5

2.0

2.5

Black White Hispanic Male Female

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Abuse or Dependence in Whites

0.0

1.0

2.0

3.0

4.0

5.0

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Marijuana Abuse or Dependence in Blacks

0.0

1.0

2.0

3.0

4.0

5.0

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Marijuana Abuse or Dependence in Hispanics

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Marijuana Abuse or Dependence in Men

0

1

2

3

4

5

6

7

Total 18-29 30-44 45-64

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Marijuana Abuse or Dependence in Women

0.0

0.5

1.0

1.5

2.0

2.5

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

• Rates increased significantly overall• Increases in rates were significant for:

– 18-29 and 45-64 year olds overall– Blacks and Hispanics overall and 18-29

years old– Women overall and 18-29 years old– Men 45-64 years old– Black and Hispanic men overall and 18-29

years old– Black women overall and 18-29 years old

Results: Summary of Marijuana Abuse or Dependence

Results: Marijuana Abuse or Dependence Among Users in Overall Population

05

1015202530354045

Total 18-29 30-44 45-64

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Abuse or Dependence among Users, by Sex and Race/Ethnicity

0

5

10

15

20

25

30

35

40

Black White Hispanic Male Female

NLAES 1991-1992 NESARC 2001-2002

= p < .05

%

Results: Marijuana Abuse or Dependence Among Black Users

05

1015202530354045

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Abuse or Dependence Among White Users

05

1015202530354045

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Abuse or Dependence Among Hispanic Users

05

1015202530354045

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Abuse or Dependence Among Male Users

0

10

20

30

40

50

Total 18-29 30-44 45-64

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

Results: Marijuana Abuse or Dependence Among Female Users

0

5

10

15

20

25

30

35

Total 18-29 30-44

NLAES 1991-1992 NESARC 2001-2002= p < .05

%

• Rates increased significantly overall

• Increases in rates were significant for:

– 18-29 and 30-44 year olds overall

– Blacks overall and 30-44 and 18-29 years old

– Hispanics overall and 18-29 years old

– Women and men overall and 18-29 years old

– Black and Hispanic men overall and 18-29 years old

– Black women overall and 18-29 years old

Results: Summary of Marijuana Abuse or Dependence Among Users

Estimated Population Increases in Marijuana Abuse or Dependence

10%

26%

35%

29%38%

38%

10%

14%Male Female

20%

26%

24%

30%

White

Black

Hispanic

Other

Total

Why have rates increased?

• Changes in quantity/frequency of marijuana use?

• Changes in potency of marijuana?

• Psychosocial factors?

Why have rates increased?

Changes in quantity/frequency of marijuana use?

Not likely…

Changes in Frequency of MJ Use?

0

5

10

15

20

25

30

35

40

<1 dy/mo 1-3 dys/mo 1-4 dys/wk 5-7dys/wk

1991-1992 2001-2002

%

Changes in Quantity of MJ Smoked?

0

10

20

30

40

50

60

70

1 Joint 2-3 Joints 4-6 Joints 7+ Joints

1991-1992 2001-2002

%

Why have rates increased?

Changes in potency of marijuana?

Possibly…

Changes in Potency of Marijuana

0%

1%

2%

3%

4%

5%

6%

7%

1991

1993

1995

1997

1999

2001

Δ9-THC

Source: Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi; 2003

Why have rates increased?

Psychosocial factors?

Possibly…

Plausible Psychosocial Factors

• Acculturation?

• Lifestyle factors and attitudinal factors?

• Sociodemographic or socioeconomic factors?

• Economic factors such as price, tax and policy changes affecting other substances that may inadvertently affect marijuana?

• Historical and cultural factors?

Summary

• Rates of Marijuana use were nearly the same in the total population in 1991-1992 as in 2001-2002, but increases were seen in certain subgroups:

– younger male and female blacks,

– younger Hispanic males

– white and black 45-64 year olds.

• Marijuana-related disorders (abuse and dependence) increased from 1991-1992 to 2001-2002, especially for younger male and female blacks and younger hispanic males.

• Increased potency of marijuana may play a role

Summary

Marijuana Use Disorders in the United States: 1991-1992 and 2001-2002

Wilson M. Compton, M.D., M.P.E. - NIDA

Bridget F. Grant, Ph.D., Ph.D. - NIAAA

James D. Colliver, Ph.D. - NIDA

Meyer D. Glantz, Ph.D. - NIDA

Frederick S. Stinson, Ph.D. - NIAAA