The role of serotonin receptor alleles and environmental stressors in the development of post-concussive symptoms after pediatric mild traumatic brain injury

AimTo determine whether post-injury depressive symptoms, and pre-injury major life stressors and genetic factors (HTR1A C(-1019)G alleles; rs6295) are more common in children with mild traumatic brain injury (mTBI) who develop postconcussion syndrome (PCS) symptoms compared with children with asymptomatic mTBI. MethodThis was a cross-sectional study of 47 symptomatic children (32 males, 15 females; mean age 14y [SD 3y 3mo]) who experienced post-concussive symptoms for 7 or more days and 42 asymptomatic children (26 males 16 females; mean age 13y 6mo [SD 3y 1mo]) after mTBI. Outcome measures were the Postconcussion Symptoms Inventory (PCSI), the Children's Depression Inventory (CDI), standard questionnaire of previous life events, and buccal DNA analysis to determine genotype and allele frequencies for the HTR1A C(-1019)G polymorphism. ResultsDepressive symptoms were uncommon. CDI scores did not differ between groups. Allelic and genotypic frequencies for HTR1A C(-1019)G were similar in both groups. Symptomatic children continued to have elevated PCS scores compared with asymptomatic children 1.72 (SD 0.69) years later and had experienced significantly more life stressors (Wald (1)=8.51, p=0.004). InterpretationHTR1A polymorphisms do not differ in children with PCS. Children who have experienced more significant life stresses are more likely to develop PCS symptoms after mTBI.