Blunted Heart Rate Response as a Potential Endophenotype of Substance Use Disorders: Evidence from High-Risk Youth.
BACKGROUND
Children of parents with a substance use disorder (CPSUD) are at increased risk for developing problematic substance use later in life. Endophenotypes may help to clarify the mechanism behind this increased risk. However, substance use and externalizing symptoms may confound the relation between dysregulated physiological stress responding and familial risk for substance use disorders (SUDs).


METHODS
We examined whether heart rate (HR) responses differed between CPSUDs and controls. Participants (aged 11-20 years) were CPSUDs (N = 75) and controls (N = 363), semi-matched on the basis of sex, socioeconomic status, and ethnicity. HR was measured continuously during a psychosocial stress procedure. Substance use and externalizing symptoms were self-reported and mother-reported, respectively.


RESULTS
A piecewise, mixed-effects model was fit for HR across the stress procedure, with fixed effects for HR reactivity and HR recovery. CPSUDs showed a blunted HR recovery. CPSUDs reported drinking more frequently, were more likely to use tobacco daily, were more likely to report ever use of cannabis and used cannabis more frequently, and exhibited more externalizing symptoms. These variables did not confound the relation between familial risk for SUDs and a blunted HR recovery.


CONCLUSIONS
Our findings suggest dysregulated autonomic nervous system (ANS) responding in CPSUDs and contribute to the accumulating evidence for ANS dysregulation as a potential endophenotype for SUDs.
Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Sophia Children's Hospital , Rotterdam , Netherlands ; Department of Developmental Psychology, EMGO Institute for Health and Care Research, VU University Amsterdam , Amsterdam , Netherlands ; Behavioral Science Institute, Radboud University , Nijmegen , Netherlands.
Brittany E
BE
Evans
Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Sophia Children's Hospital , Rotterdam , Netherlands.
Kirstin
K
Greaves-Lord
Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Sophia Children's Hospital , Rotterdam , Netherlands ; Department of Psychology, Erasmus University Rotterdam , Rotterdam , Netherlands.
Anja S
AS
Euser
Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Sophia Children's Hospital , Rotterdam , Netherlands.
Tess
T
Koning
Department of Psychiatry, Erasmus University Medical Center , Rotterdam , Netherlands.
Joke H M
JH
Tulen
Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Sophia Children's Hospital , Rotterdam , Netherlands ; Department of Psychology, Erasmus University Rotterdam , Rotterdam , Netherlands.
Ingmar H A
IH
Franken
Department of Developmental Psychology, EMGO Institute for Health and Care Research, VU University Amsterdam , Amsterdam , Netherlands.
Anja C
AC
Huizink
externalizing; familial risk; heart rate; stress reactivity; substance use disorders