Transcript Effects of pharmacological treatment on the educational

University of Copenhagen
Department of Sociology
The Effect of Medical Treatment on the Educational
Achievement of Children Diagnosed with Attention
Deficit/Hyperactivity Disorder (ADHD)
Maria Keilow1
Anders Holm1,2,3
Peter Fallesen2,3
EUSARF conference, September 4th 2014
SFI – The Danish National Centre for Social Research
2 University of Copenhagen, Department of sociology
3 Rockwool Foundation Research Unit
1
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
University of Copenhagen
Department of Sociology
OUTLINE
•
Background
•
Research question
•
Data
•
Methods
•
Results
•
Conclusion
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
2
University of Copenhagen
Department of Sociology
BACKGROUND
• Estimated prevalence of Attention Deficit/Hyperactivity Disorder
(ADHD) in Denmark is 6,4% among school aged children
(Petersen et al., 2006)
• ADHD is associated with worse social trajectories and reduced
educational attainment
(e.g., Currie and Stabile, 2004)
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
3
University of Copenhagen
Department of Sociology
BACKGROUND
• Increase in share of children diagnosed with ADHD before age 10
within each birth cohort
1.4
1.2
1
0.8
0.6
0.4
0.2
0
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
• 1,650 pct. increase in number of ADHD medication users from 20002011 (Danish Health and Medicines Authority, 2012)
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
4
University of Copenhagen
Department of Sociology
BACKGROUND
Social science studies
• Long-term negative impact of ADHD on education
• Rarely account for or study treatment
(exceptions are Dalsgaard et al., 2012;
2013; Currie et al., 2004; 2013 - no sign. medium/long-term effect on marginal child)
Medical studies
• Short-term positive effects of medicine on core symptoms of ADHD
and on cognitive achievement outcomes measured in clinical settings
(e.g., Carlson & Bunner, 1993)
• Ambiguous or insignificant long-term effects on education and studies
suffer from methodological challenges (e.g. imperfect randomisation)
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
5
University of Copenhagen
Department of Sociology
RESEARCH QUESTION
• Does medical treatment improve long-term
educational achievement of children diagnosed
with ADHD?
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
6
University of Copenhagen
Department of Sociology
DATA
• Danish administrative registers on education (2002-)
- Educational achievement outcomes (school-leaving GPA)
- Individual and family background information
• Danish Registry of Medical Product Statistics (1995-)
- Sample identification through ADHD medication use
- ADHD treatment patterns
- Intend to treat
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
7
University of Copenhagen
Department of Sociology
DATA
Primary sample
• 2002-2011 compulsory school graduates Diagnosed with ADHD
• Begin medical treatment prior to 9th grade (graduation)
• Birth cohorts 1984-1996
• Sample size: 3738
7/17/2015
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders Holm
and Peter Fallesen
8
University of Copenhagen
Department of Sociology
All compulsory school
graduates
All compulsory school
graduates with ADHD
All compulsory school graduates
diagnosed with ADHD
All compulsory school
graduates diagnosed
with ADHD
who begin medical
treatment
Primary sample
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
9
University of Copenhagen
Department of Sociology
DATA
Outcomes
• Standardized total GPA from 9th grade school-leaving finals
Exam
Teacher Evaluation
Treatment
• No treatment
Immediate discontinuance of medical treatment
Non-responders
• Inconsistent treatment
Inconsistent medical treatment with breaks
• Treatment (ref.)
Consistent medical treatment with no breaks
Controls
• Individual and family characteristics plus birth cohort and region FE
7/17/2015
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders Holm
and Peter Fallesen
10
Select descriptive statistics
Male
Gestational age (weeks)
Birth weight (grams)
Immigrant or descendant
M is ADHD-diagnosed
F is ADHD-diagnosed
M education ISCED 2
- ISCED 3A
- ISCED 3C
- ISCED 5B
- ISCED 5AC + 6
F education ISCED 2
- ISCED 3A
- ISCED 3C
- ISCED 5B
- ISCED 5AC + 6
M yearly income (euro)
F yearly income (euro)
M unemployment rate
F unemployment rate
N
Population
ADHD sample
Mean
SD
0.50
0.50
40
1.80
3461
567
0.09
0.22
0.01
0.07
0.00
0.07
0.17
0.38
0.08
0.28
0.38
0.49
0.19
0.39
0.04
0.22
0.12
0.32
0.05
0.22
0.40
0.49
0.11
0.31
0.07
0.30
28600
15000
41500
38000
139
254
76
192
570958
Mean
SD
0.74*
0.44
39*
2.05
3456
620
0.04*
0.15
0.09*
0.29
0.05*
0.22
0.23*
0.42
0.09
0.29
0.42*
0.49
0.15*
0.36
0.03*
0.18
0.16*
0.37
0.04*
0.20
0.41
0.49
0.09*
0.29
0.06*
0.23
28300
12300
39600*
20100
170*
272
98*
217
3738
Notes: M = Mother, F = Father, * p < 0.05
17-07-2015
University of Copenhagen
Department of Sociology
METHOD
Main ID-strategy: Medical non-response is random
• Double blind placebo RCTs since the 1960s find that 25-30% of
ADHD patients are medical non-responders
• No individual or family characteristics predict medicine response
(Barkley, 1977; Spencer et al., 1996; Pelham & Smith, 2000)
 support medical efficacy (non-response) being random
• All sample children begin medical treatment, but some discontinue
treatment immediately
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
12
University of Copenhagen
Department of Sociology
METHOD
Main ID-strategy: Medical non-response is random
Assumptions
• Sample children/families likely expect positive treatment effects
• Severity of ADHD symptomology comparable within sample
• Treatment non-response is exogenous
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
13
Subsample means
Male
Birth weight
Gestational age
Immigrant/descendant
Age at treatment start
Birth cohort
M is ADHD-diagnosed
M education ISCED 2
- ISCED 3A
- ISCED 3C
- ISCED 5B
- ISCED 5AC + 6
M yearly income
M unemployment rate
F is ADHD-diagnosed
F education ISCED 2
- ISCED 3A
- ISCED 3C
- ISCED 5B
- ISCED 5AC + 6
F yearly income
F unemployment rate
N
Notes: M = Mother, F = Father
No treatment
(NT)
0.71
3419
39
0.08
13
1992
0.05
0.17
0.11
0.41
0.13
0.05
29400
185
0.01
0.13
0.04
0.39
0.09
0.07
40000
97
403
Inconsistent
treatment (IT)
0.77
3456
39
0.04
13
1992
0.09
0.24
0.09
0.41
0.16
0.03
28200
168
0.05
0.17
0.04
0.40
0.09
0.06
39300
98
2761
t-tests
Treatment
(T)
0.63
3481
39
0.03
14
1994
0.11
0.20
0.11
0.47
0.16
0.03
27700
170
0.06
0.16
0.04
0.46
0.09
0.04
40500
99
574
NT vs. T
IT vs. T
NT vs. IT
2.72
6.32
-2.28
3.51
-7.98
-11.19
-3.63
2.86
-15.24
-21.63
2.54
-3.32
-3.45
-2.59
-4.47
-2.36
17-07-2015
-5.48
-2.05
-2.71
University of Copenhagen
Department of Sociology
METHOD
1. Supplementary ID-strategy: Placebo regressions
• Placebo sample regression models for children, who begin treatment
after outcomes are measured
• Placebo sample is drawn from same population as primary sample
• Placebo data allow us to test ignorability assumption (random
assignment to treatment efficiency)
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
15
University of Copenhagen
Department of Sociology
METHOD
1. Supplementary ID-strategy: Placebo regressions
Assumptions
• Placebo and primary samples should not differ sign. on covariates
• We should expect no significant effects of treatment on GPA,
conditional on background covariates, for children in placebo sample
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
16
University of Copenhagen
Department of Sociology
METHOD
1. Supplementary ID-strategy: Placebo regressions
Placebo sample
• 2002-2011 compulsory school graduates diagnosed with ADHD
• Begin medical treatment at 2+ years after graduation
• Birth cohorts 1984-1994
• Sample size: 3784
7/17/2015
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders Holm
and Peter Fallesen
17
University of Copenhagen
Department of Sociology
METHOD
2. Supplementary ID-strategy: Region as IV
Regional variation in Denmark in share of children in medical ADHD
treatment
To allow for endogeneity of treatment continuance, I instrument effect of
no treatment using residential region at age two
Main equation include birth cohort fixed effects and region FE at
graduation year
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
18
University of Copenhagen
Department of Sociology
METHOD
2. Supplementary ID-strategy: Region as IV
Assumptions
•
Instrument does not enter the main equation (independence
assumption), i.e. no direct effect of instrument on GPA outcomes
•
Instruments must be correlated with treatment (instrument
relevance)
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
19
University of Copenhagen
Department of Sociology
RESULTS
Note that…
• Inverse treatment estimates: Impact of no treatment or inconsistent
treatment compared to consistent treatment (ref.)
• Models weighted with propensity of being treated (ref.)
• Birth cohort FE included to account for nonrandom selection into
sample across successive cohorts
• Estimates presented for primary and placebo sample, respectively
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
20
University of Copenhagen
Department of Sociology
Estimation results for treatment variables (treatment is ref.)
Models include all controls
Std. total GPA outcomes
Exam GPA
No treatment
Inconsistent treatment
Birth cohort FE
Region FE
N
Teacher Evaluation GPA
No treatment
Inconsistent treatment
Birth cohort FE
Region FE
N
OLS
Weighted
OLS
IV
Placebo
OLS
Placebo
weighted OLS
-0.17**
(0.06)
-0.12*
(0.05)

-0.25***
(0.07)
-0.20***
(0.05)

-0.05
(0.03)
-0.05
(0.03)

-0.05
(0.04)
-0.05
(0.04)

3738
3728
-1.43*
(0.61)


3738
3785
3784
-0.17**
(0.06)
-0.90
(0.05)

-0.21**
(0.07)
-0.15**
(0.05)

-0.06
(0.04)
-0.03
(0.03)

-0.05
(004)
-0.03
(0.04)

3738
3728
-0.64
(0.29)


3738
3785
3784
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
21
University of Copenhagen
Department of Sociology
Estimation results for treatment variables (treatment is ref.)
Models include all controls
Std. total exam GPA
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
22
University of Copenhagen
Department of Sociology
A general ADHD/non-ADHD GPA gap in Denmark
Estimation results for ADHD diagnosis
Sample: All 2002-2011 graduates
Std. total GPA outcomes
OLS
no controls
Exam GPA
ADHD diagnosis
Birth cohort FE
N
Teacher Evaluation GPA
ADHD diagnosis
Birth cohort FE
N
-0.66***
(0.01)
570958
-0.75***
(0.01)
570958
OLS
with controls
Weighted OLS
with controls
-0.53***
(0.01)

570958
-0.57***
(0.01)

570958
-0.60***
(0.01)

570958
-0.66***
(0.01)

570958
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
23
University of Copenhagen
Department of Sociology
A general ADHD/non-ADHD GPA gap in Denmark
Estimation results for ADHD diagnosis
Sample: 2nd grade students year 2012
Std. national test scores from Danish reading test
OLS
with controls
OLS
with controls
OLS
with controls
Decoding
Text
comprehension
-0.15***
(0.04)

59659
Std. test scores
ADHD diagnosis
Birth cohort FE
N
Language
comprehension
-0.4
(0.04)

59659
-0.35***
(0.04)

59659
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
24
University of Copenhagen
Department of Sociology
CONCLUSION
• Medical treatment has a sizeable impact on long-term educational
outcomes of children diagnosed with ADHD
• No treatment or inconsistent treatment is detrimental compared to
consistent treatment, reducing total exam and teacher evaluation GPA
• Children studied included in the study likely have moderate to severe
symptoms
• Due considerations should be given to the benefit of medicine vs. nonmedical treatment or combinations – aspects not addressed here
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
25
University of Copenhagen
Department of Sociology
Thank you.
Maria Keilow
[email protected]
The Effect of Medical Treatment on the Educational Achievement of Children Diagnosed with ADHD – Maria Keilow, Anders 17-07-2015
Holm and Peter Fallesen
26