Temporal changes in N‐acylethanolamine content and metabolism throughout the peri‐adolescent period

Fatty acid amide hydrolase (FAAH) regulates tissue concentrations of N‐acylethanolamines (NAEs), including the endocannabinoid, N‐arachidonylethanolamide (anandamide, AEA). FAAH activity and NAEs are widely distributed throughout the brain and FAAH activity regulates an array of processes including emotion, cognition, inflammation, and feeding. However, there is relatively little research describing how this system develops throughout adolescence, particularly within limbic circuits regulating stress and reward processing. Thus, this study characterized temporal changes in NAE content (AEA, oleoylethanolamine [OEA], and palmitoylethanolamide [PEA]) and FAAH activity across the peri‐adolescent period, in four corticolimbic structures (amygdala, hippocampus, prefrontal cortex, and hypothalamus). Brain tissue of male Sprague–Dawley rats was collected on postnatal days (PND) 25, 35, 45, and 70, representing pre‐adolescence, early‐ to mid‐adolescence, late adolescence, and adulthood, respectively. Tissue was analyzed for AEA, OEA, and PEA content as well as FAAH activity at each time point. AEA, OEA, and PEA exhibited a similar temporal pattern in all four brain regions. NAE concentrations were lowest at PND 25 and highest at PND 35. NAE concentrations decreased between PNDs 35 and 45 and increased between PNDs 45 and 70. FAAH activity mirrored the pattern of NAE content in which it decreased between PNDs 25 and 35, increased between PNDs 35 and 45, and decreased between PNDs 45 and 70. These age‐dependent patterns of NAE content and FAAH activity demonstrate temporal specificity to the development of this system and could contribute to alterations in stress sensitivity, emotionality, and executive function which also fluctuate during this developmental period. Synapse, 2013. © 2012 Wiley Periodicals, Inc.     

Prospective relations between alexithymia,substance use and depression: findings from a National Birth Cohort

Abstract

Purpose: This study examined a developmental model that links affect-regulation difficulties in childhood with three dimensions of alexithymia in adolescence (difficulty identifying feelings, difficulty describing feelings, and externally oriented thinking) and substance use and depression in adulthood, while accounting for cumulative contextual risk in childhood, and testing potential gender moderation.

Methods: Multiple group path analyses were conducted using data from the Northern Finland Birth Cohort 1986 (N?=?6963). Analyses used data collected during prenatal/birth, childhood, adolescence, and young adulthood periods.

Results: Our examination of early precursors for alexithymia indicated that the associations of affect-regulation problems in childhood with alexithymia were stronger for girls, potentially putting girls with affect-regulation difficulties in childhood at higher risk for developing alexithymia in adolescence. The associations of cumulative contextual risk in childhood with alexithymia, substance use disorder, and depression diagnosis in adulthood were significant for both girls and boys. Our findings in regard to substance use and depression disorders revealed that alexithymia in adolescence predicted depression diagnosis in adulthood, particularly due to a contribution from the alexithymia domain of ‘difficulties identifying feelings.’ However, none of the alexithymia domains was directly associated with substance use disorder in adulthood.

Conclusions: Our study contributes to research that links alexithymia with difficulties in affect regulation and cumulative contextual risk in childhood, yielding findings that may be relevant for preventive interventions.     

Isolation rearing and hyperlocomotion are associated with reduced immediate early gene expression levels in the medial prefrontal cortex

Environmental deprivation contributes in important ways to the development of a wide range of psychiatric disorders. Isolation rearing of rodents, a model for environmental deprivation in humans, consistently produces hyperlocomotion, which provides a measurable parameter to study the underlying mechanisms of early adverse psychosocial stressors. Male Sprague-Dawley rat pups were separated from dams at postnatal (PN) day 20 and reared either in groups of three or in isolation. On PN 38, locomotion was assessed in the open field. On PN 46, rats were killed and gene expression patterns examined in the medial prefrontal cortex (mPFC). Isolation-reared rats displayed increased locomotor activity and decreased resting time in the open field. Specific gene expression patterns in the mPFC were associated with both isolation rearing and hyperlocomotive behavior in the open field. Genes involved in these expression patterns included immediate early genes (IEGs) and genes that regulate cell differentiation and apoptosis. The study of these genes could provide important insights into how abnormal early psychosocial events affect brain function and behavior.     

Relations among multiple peer influences, body dissatisfaction, eating disturbance, and self-esteem: a comparison of average weight, at risk of overweight, and overweight adolescent girls

OBJECTIVE: The goal of this study was to evaluate peer-related influences on appearance, body dissatisfaction, eating disturbance, and self-esteem in average weight, at risk of overweight, and overweight adolescent girls. METHODS: Three hundred twenty-five adolescent girls from high schools in Florida were assessed. Ninety met criteria for being at risk of overweight or overweight. Logistic and multiple regression analyses were used to evaluate group differences on all variables and to assess the amount of variance accounted for by peer-influence variables in the prediction of body dissatisfaction, eating disturbance, and self-esteem. RESULTS: Overweight and at risk of overweight girls scored higher than average weight girls on body dissatisfaction, dieting, and a peer measure that assessed negative comments and attributions about appearance. They also scored lower than average weight girls on self-report measures that assessed conversations about appearance and anti-dieting advice. How influential friends were in determining one's body image was a unique predictor of body dissatisfaction but only for the overweight and at risk of overweight group. CONCLUSIONS: Possible implications for clinical intervention programs are discussed along with directions for future research.     

The Relationship between Vigorous Physical Activity and Juvenile Delinquency: A Mediating Role for Self-Esteem?

Many policy-related reviews of the potential social value of sport and physical activity list the prevention of juvenile delinquency. We examined the relationships among vigorous physical activity, self-esteem, and delinquent behavior among adolescents in a large cross-sectional survey of Ontario adolescents. Data are based on questionnaires from 3,796 students (range 11–20 years) derived from the 2005 Ontario Student Drug Use Survey. Negative binominal regression methods were used to estimate both additive and interactive models predicting delinquent behavior. Vigorous physical activity was positively associated with delinquent behavior; however, this pattern of association was observed only among male adolescents. There was no evidence of a mediating role for self-esteem. Our findings suggest that physical activity is not the solution for reducing juvenile delinquency.