Dopamine and serotonin transporter genotypes moderate sensitivity to maternal expressed emotion: the case of conduct and emotional problems in attention deficit/hyperactivity disorder.
BACKGROUND
Mothers' positive emotions expressed about their children with attention deficit/hyperactivity disorder (ADHD) are associated with a reduced likelihood of comorbid conduct problems (CP). We examined whether this association with CP, and one with emotional problems (EMO), is moderated by variants within three genes, previously reported to be associated with ADHD and to moderate the impact of environmental risks on conduct and/or emotional problems; the dopamine transporter gene (SLC6A3/DAT1), the dopamine D4 receptor gene (DRD4) and the serotonin transporter gene (SLC6A4/5HTT).


METHODS
Seven hundred and twenty-eight males between the ages of 5 and 17 with a DSM-IV research diagnosis of combined type ADHD were included in these analyses. Parents and teachers rated children's conduct and emotional problems. Positive maternal expressed emotion (PMEE) was coded by independent observers on comments made during a clinical assessment with the mother based on current or recent medication-free periods.


RESULTS
Sensitivity to the effects of PMEE on CP was moderated by variants of the DAT1 and 5HTT genes. Only children who did not carry the DAT1 10R/10R or the 5HTT l/l genotypes showed altered levels of CP when exposed to PMEE. The effect was most marked where the child with ADHD had both these genotypes. For EMO, sensitivity to PMEE was found only with those who carried the DAT1 9R/9R. There was no effect of DRD4 on CP or EMO.


CONCLUSIONS
The gene-environment interactions observed suggested that genetic make-up can alter the degree of sensitivity an ADHD patients has to their family environment. Further research should focus on distinguishing general sensitivity genotypes from those conferring risk or protective qualities.
Sonuga-Barke
Edmund J S
EJ
Developmental Brain-Behaviour Laboratory, School of Psychology, University of Southampton, Southampton, UK. ejb3@soton.ac.uk
Oades
Robert D
RD
Psychogiou
Lamprini
L
Chen
Wai
W
Franke
Barbara
B
Buitelaar
Jan
J
Banaschewski
Tobias
T
Ebstein
Richard P
RP
Gil
Michael
M
Anney
Richard
R
Miranda
Ana
A
Roeyers
Herbert
H
Rothenberger
Aribert
A
Sergeant
Joseph
J
Steinhausen
Hans Christoph
HC
Thompson
Margaret
M
Asherson
Philip
P
Faraone
Stephen V
SV
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics* / Q000523:psychology; D002648:Child; D002653:Child Behavior Disorders / Q000150:complications / Q000235:genetics; D002675:Child, Preschool; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics*; D019260:Expressed Emotion; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D009034:Mother-Child Relations; D050638:Receptors, Dopamine D4 / Q000235:genetics; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*
C493599:DRD4 protein, human; D050483:Dopamine Plasma Membrane Transport Proteins; C493214:SLC6A3 protein, human; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D050638:Receptors, Dopamine D4