Stéphane Paquin, Eric Lacourse, Mara Brendgen, Michel Boivin

Stéphane Paquin, Eric Lacourse, Mara Brendgen, Michel Boivin

Development of physical aggression during childhood: A dynamic genome?
Stéphane Paquin, Eric Lacourse, Mara Brendgen, Michel Boivin, Ginette Dionne,
Frank Vitaro & Richard Tremblay
Context
Genetic effect is often conceived as stable over time even if we are accumulating evidence of dynamic effects occurring over time (van Beijsterveldt, C. E. M & al. 2003; Silberg, J. L. & al. 2007).
3.  Developmentally dynamic genetic effect were Objectives
Figure 2. Genetic components from Cholesky decomposition of aggressive behavior
identified
a.  Genetic innovation
b.  Genetic a@enuation
Identify and detail the temporal pa@ern of genetic and environmental effects on the level of aggression during childhood (6 to 11 years).
1
0.8
Results
1.  Mean level of aggression is relatively stable during childhood
Table 1. Means and MZ/DZ Intraclass Correlations
Age$
6$years$$
$
$
$
Means$(sd)$
.79$(1.39)$
$
$
MZ/DZ$Intraclass$correlations$
6$years$
.72$/$.32$
7$years$
.14$
9$years$
.04$
10$years$
.09$
11$years$
.04$
7$years$
$
.81$(1.43)$
$
$
.39$
.58$/$.29$
.17$
.18$
.09$
9$years$
$
.79$(1.43)$
$
$
.23$
.35$
.50$/$.23$
.18$
.07$
$
Abbreviations.$MZ$monozygotic$twin$pairs,$DZ$dizygotic$twin$pairs$
a$MZ$above$the$diagonal,$DZ$below$the$diagonal$
10$years$
$
.74$(1.34)$
$
$
.31$
.38$
.32$
.70$/$.39$
.17$
11$years$
$
.43$(1.03)$
$
$
.24$
.34$
.27$
.41$
.63$/$.19$
2.  Genetic factors play an important role throughout childhood
0.6
0.4
0.2
0
6
7
9
10
11
A_1 A_2 A_3 A_4 A_5
4.  Both innovation and a@enuation were identified for unique environmental effects
5.  No shared environmental effect were identified
Figure 3. Unique environment components from Cholesky decomposition of aggressive behavior
0.8
Figure 1. Genetic (A) and unique environment (E) components throughout childhood
0.6
100%
80%
26.7%
45.0%
49.5%
33.2%
43.5%
0.4
60%
40%
0.2
73.3%
20%
0%
6
55.0%
7
50.5%
9
66.8%
56.5%
0
10
6
7
9
10
E_1 E_2 E_3 E_4 E_5
11
A E
Design / participants
Main outcome
5 waves of an ongoing longitudinal twin study. 675 twin pairs: 122 had missing values on all 5 waves, 223 MZ and 330 DZ twins had at least 1 observed value. No sex-­‐‑
differences were identified in the covariance structure. Modeling was done in Mplus v7.0.
Aggressive behavior measured by three items from the CBCL: fighting, physically a@acking others, and hit, bite or kicks other. A log normal transformation was applied to minimize skewness of the raw scores. 11