Psychosocial Risk Factors And5-HT Related Gene Polymorphisms In Male Juvenile Delinquency

Objective:1. To investigate the psycho-social characteristics of male juvenile offenders, and understand their risk factors of violent and non-violent crime.2. To understand the genetic features in male juvenile offenders, especially the gene polymorphisms of serotonin system including TPH1A218C, TPH2G-703T, HTR1B G861C, BDNF Va166Met, NOS1ex1f-VNTR gene polymorphisms.Methods:1. There were three hundred and eighty-four male juvenile offenders (include257violent offenders,127non-violent offenders, aged14-19) recruited from three juvenile reformatory. Eighty-three normal male high school students, matched age and sex with offenders, were included as control group. Assessing instruments include a self-developed questionnaire of background data, Family Adaptability and Cohesion Evaluation Scales-II (FACES-II), Social Support Rating Scales (SSRS), Coping Style Questionnaire, Adolescent Self-Rating Life Events Check List (ASLEC), Barratt Impulsiveness Scale (BIS-11) and Stroop Color-Word Test (CWT).2. There were two hundred and two violent juvenile offenders and101non-violent juvenile offenders in part1who provided venous blood samples were included in present study. One hundred and forty-seven normal high school students (include part1control group and another high school students) were included as control group. Polymerase chain reaction-ligase detection reaction (PCR-LDR) was used to test genotypes. Then we compared the genotypes and alleles distributions of the above-mentioned gene polymorphisms. Gene-gene interaction between groups was analyzed by Multifactor dimensionality reduction (MDR) method.Results: 1. There were significant difference in family function, social support, adolescent life events, impulsivity and cognitive function between juvenile offenders and normal high school students (P<0.05). Logistic regression analysis showed that negative parental rearing, major frustration, low social support, the total black reading time of CWT, smoking, drinking and punished times in school were the risk factors of violent crime. Negative parental rearing, do not live with parents, immature copying styles, the total black reading time of CWT, smoking, drinking and punished times in school were the risk factors of non-violent crime. Moreover, compared with non-violent offenders, violent offenders had lower social support, higher impulsivity, poorer family adaptability. Logistic regression analysis using violent and non-violent offenders as dependent factors showed that frequent change of caregivers, major frustration, low social support and high impulsivity were the risk factors of violent crimes, while short time for living with parents, the longer black reading time of CWT were the risk factors of non-violent crimes.2. Compared with normal high school students and violent offenders, non-violent juvenile offenders had higher frequency of HTR1B rs6296C allele(x2=6.087, P=0.014; x2=3.823, P=0.050). Gene-gene interaction analysis showed that the interaction among TPH1A218C, TPH2G-703T, HTR1B G861C, BDNF Va166Met, NOS1ex1f-VNTR gene polymorphisms was in statistical significance when compared violent offenders with non-violent offenders(TBA=0.596, CVC=10/10, p=0.001), and NOS1ex1f-VNTR and TPH1A218C had strong synergy. When compared non-violent offenders with normal school students, the interaction among HTR1B rs6296, TPH2rs4570625and TPH1rsl800532was close to statistical significance (TBA=0.5693, CVC=9/10, p=0.051).Conclusions:1. Juvenile offenders have more negative environment risk factors, poorer personal qualities and more problem behaviors. Moreover, negative parental rearing, problem behavior patterns are common risk factors of violent and non-violent offenders.2. Violent and non-violent offenders have different risk factors. Caregivers change frequently, major frustration, low social support and high impulsivity are the risk factors of violent crimes, while short time for living with parents, slower information processing are the risk factors of non-violent crimes.3. HTR1B rs6296C allele may be associated with non-violent crimes. The interaction among TPH1A218C, TPH2G-703T, HTR1B G861C, BDNF Va166Met, NOS1ex1f-VNTR gene polymorphisms may have influence on types of crimes, which would increase the risk of individual developing to violent offenders, but the influence is relative small.