Aggressive behavior, related conduct problems, and variation in genes affecting dopamine turnover.

A number of dopamine-related genes have been implicated in the etiology of violent behavior and conduct problems. Of these genes, the ones that code for the enzymes that influence the turnover of dopamine (DA) have received the most attention. In this study, we investigated 12 genetic polymorphisms in four genes involved with DA functioning (COMT, MAOA and MAOB, and DbetaH) in 179 incarcerated male Russian adolescents and two groups of matched controls: boys without criminal records referred to by their teachers as (a) "troubled-behavior-free" boys, n=182; and (b) "troubled-behavior" boys, n=60. The participants were classified as (1) being incarcerated or not, (2) having the DSM-IV diagnosis of conduct disorder (CD) or not, and (3) having committed violent or nonviolent crimes (for the incarcerated individuals only). The findings indicate that, although no single genetic variant in any of the four genes differentiated individuals in the investigated groups, various linear combinations (i.e., haplotypes) and nonlinear combinations (i.e., interactions between variants within and across genes) of genetic variants resulted in informative and robust classifications for two of the three groupings. These combinations of genetic variants differentiated individuals in incarceration vs. nonincarcerated and CD vs. no-CD groups; no informative combinations were established consistently for the grouping by crime within the incarcerated individuals. This study underscores the importance of considering multiple rather than single markers within candidate genes and their additive and interactive combinations, both with themselves and with nongenetic indicators, while attempting to understand the genetic background of such complex behaviors as serious conduct problems.

Association of higher parental and grandparental education and higher school grades with risk of hospitalization for eating disorders in females: the Uppsala birth cohort multigenerational study.

Eating disorders are a leading cause of disease burden among young women. This study investigated associations of social characteristics of parents and grandparents, sibling position, and school performance with incidence of eating disorders. The authors studied Swedish females born in 1952-1989 (n = 13,376), third-generation descendants of a cohort born in Uppsala in 1915-1929. Data on grandparental and parental social characteristics, sibling position, school grades, hospitalizations, emigrations, and deaths were obtained by register linkages. Associations with incidence of hospitalization for eating disorders were studied with multivariable Cox regression, adjusted for age and study period. Overall incidence of hospitalization for eating disorders was 32.0/100,000 person-years. Women with more highly educated parents and maternal grandparents were at higher risk (hazard ratio for maternal grandmother with higher education relative to elementary education = 6.5, 95% confidence interval: 2.2, 19.3, adjusted for parental education). Independent of family social characteristics, women with the highest school grades had a higher risk of eating disorders (hazard ratio = 7.7, 95% confidence interval: 2.5, 24.1 for high compared with low grades in Swedish, adjusted for parental education). Thus, higher parental and grandparental education and higher school grades may increase risk of hospitalization for eating disorders in female offspring, possibly because of high internal and external demands.

Association between polymorphisms in the dopamine transporter gene and depression: evidence for a gene-environment interaction in a sample of juvenile detainees.

Previous research has generated examples of how genetic and environmental factors can interact to create risk for psychopathology. Using a gene-by-environment (G x E) interaction design, we tested whether three polymorphisms in the dopamine transporter gene (DAT1, also referred to as SLC6A3, located at 5p15.33) interacted with maternal parenting style to predict first-onset episodes of depression. Participants were male adolescents (N= 176) recruited from a juvenile detention center in northern Russia. As hypothesized, one of the polymorphisms (rs40184) moderated the effect of perceived maternal rejection on the onset of major depressive disorder, as well as on suicidal ideation. Further, this G x E interaction was specific to depression; it did not predict clinically significant anxiety. These results highlight the need for further research investigating the moderating effects of dopaminergic genes on depression.

Childhood behaviour as related to subsequent drinking offences and violent offending: a prospective study of 11- to 14-year-old youths into their fourth decade.

BACKGROUND: Childhood hyperactivity has previously been found to be closely connected to subsequent alcohol problems and violent offending among men considered to be without major mental disorders. For others, these associations might be moderated or confounded by other factors, predominantly comorbid conduct disorder. AIMS: The purpose of the study was to investigate aspects of childhood hyperactive behaviour in relation to alcohol or violent offences in adult life, taking the possible confounders of early criminality and aggressive behaviour into account. Method A total of 192 young male law breakers and 95 non-criminal controls were followed from age 11-14 years into their thirties. Information on aspects of hyperactivity, aggressive behaviour, early criminality and later offences was included in the analyses. RESULTS: The results supported the hypothesis that aspects of childhood hyperactive behaviour were significantly associated with later drinking offences and violent offending. Further analyses revealed attention difficulties to be the component of hyperactivity most contributing to the relationship. When taking possible confounding variables into consideration, attention difficulties were related to subsequent violent offending among boys with early criminality, independently of early aggressive behaviour. Early criminality, attention difficulties and aggressive behaviour, however, often co-occurred in the same individual. Subsequent drinking offences or violent offending appeared seven times more often among individuals with all early behavioural problems as compared with those who had no such problems. CONCLUSION: Complex antisocial behaviours in adult life commonly represent persistence of complex childhood behavioural difficulties, but among young law breakers there does appear to be a subgroup of boys with a main problem of attention difficulties who go on to violent offending, even in the absence of early manifestation of aggression.