Differential regulation of cocaine-induced locomotor activity in inbred long-sleep and short-sleep mice by dopamine and serotonin systems

Associations of Childhood Maltreatment with Single and Multiple Suicide Attempts among Older Chinese Adolescents

OBJECTIVES

To test, among older Chinese adolescents, the associations of childhood maltreatment with single and multiple suicide attempts and whether these associations vary in relation to the presence of sleep disturbance.

STUDY DESIGN

We analyzed data collected from 10th to 12th graders from 7 randomly selected provinces of China in the 2015 School-based Chinese Adolescents Health Survey. There were 83 200 students who were invited to participate, and 75 715 students' questionnaires were completed and qualified for the survey. Adjusted multinomial logistic regression models were conducted to evaluate the associations of childhood maltreatment with suicide attempts.

RESULTS

Compared with no suicide attempts, each type of adjusted childhood maltreatment (physical abuse, emotional abuse, sexual abuse, physical neglect, or emotional neglect) was associated with an increased risk of single and multiple suicide attempts (P < .05). The magnitude of the aORs in multiple suicide attempters was greater than those in single suicide attempters. Moreover, the adjusted interaction effects for a single suicide attempt between each type of childhood maltreatment and sleep disturbance were all statistically significant in the multivariable multinomial logistic regression models (P < .001). However, the adjusted interaction effects for multiple suicide attempts were not significant (P > .05).

CONCLUSIONS

Maltreatment during one's childhood is associated with an increased risk of single and multiple suicide attempts among older Chinese adolescents. Sleep disturbances play a moderating role in these associations for a single suicide attempt.

Association between sleep duration, suicidal ideation, and suicidal attempts among Chinese adolescents: The moderating role of depressive symptoms

BACKGROUND

Suicidal ideation and attempts are still currently serious problems among adolescents worldwide, and there is evidence that sleep problem may be associated with increased rates of mental disorder. This study aimed to examine the associations between sleep duration and suicidal ideation and attempts among adolescents and to test whether depressive symptoms have moderating effects on the associations.

METHODS

A 3-stage, stratified cluster, random sampling method was used to collect data from 20,130 high school students in southeast China.

RESULTS

The weighted prevalence of short sleep among Chinese adolescents was 5.6% (95% CI, 5.3-6.0%), and the weighted prevalence of long sleep was 2.7% (95% CI, 2.5-3.0%). The final results demonstrated that short sleep was positively associated with suicidal ideation (AOR=2.28, 95% CI=1.96-2.66) and suicidal attempts (AOR=3.20, 95% CI=2.46-4.16), and long sleep was only significantly associated with suicidal attempts (AOR=2.47, 95% CI=1.70-3.58). Stratification analyses conducted separately for students with and without depressive symptoms demonstrated that depressive symptoms may have moderating effects on the associations between sleep duration and suicidality.

LIMITATIONS

Our study sample only included school students, and causal inference could not be examined due to the cross-sectional design.

CONCLUSIONS

Sleep duration was associated with suicidal ideation and attempts, and the association between sleep duration and suicidal attempts was U-shaped. These findings support that proper treatments services with the potential to restore adolescent normal sleep would be helpful in preventing suicidality among adolescents.

Cocaine locomotor activation, sensitization and place preference in six inbred strains of mice

BACKGROUND

The expanding set of genomics tools available for inbred mouse strains has renewed interest in phenotyping larger sets of strains. The present study aims to explore phenotypic variability among six commonly-used inbred mouse strains to both the rewarding and locomotor stimulating effects of cocaine in a place conditioning task, including several strains or substrains that have not yet been characterized for some or all of these behaviors.

METHODS

C57BL/6J (B6), BALB/cJ (BALB), C3H/HeJ (C3H), DBA/2J (D2), FVB/NJ (FVB) and 129S1/SvImJ (129) mice were tested for conditioned place preference to 20 mg/kg cocaine.

RESULTS

Place preference was observed in most strains with the exception of D2 and 129. All strains showed a marked increase in locomotor activity in response to cocaine. In BALB mice, however, locomotor activation was context-dependent. Locomotor sensitization to repeated exposure to cocaine was most significant in 129 and D2 mice but was absent in FVB mice.

CONCLUSIONS

Genetic correlations suggest that no significant correlation between conditioned place preference, acute locomotor activation, and locomotor sensitization exists among these strains indicating that separate mechanisms underlie the psychomotor and rewarding effects of cocaine.

Restraint stress and exogenous corticosterone differentially alter sensitivity to the sedative-hypnotic effects of ethanol in inbred long-sleep and inbred short-sleep mice

Decreased sensitivity to ethanol is a genetically mediated trait implicated in susceptibility to developing alcoholism. Here, we explore genotype by environment differences in ethanol sensitivity. The relationship between acute- and repeated-restraint stress, corticosterone (CORT) levels, and sensitivity to sedative-hypnotic properties of ethanol was explored using inbred long-sleep (ILS) and inbred short-sleep (ISS) mice. In ILS mice, acute restraint decreased ethanol sensitivity at a 4.1g/kg dose, as measured by a decrease in the duration of loss of the righting reflex (LORE) and an increase in blood ethanol concentration at regain of the righting response (BECRR). Repeated restraint also decreased LORE duration, but had no effect on BECRR. In the ISS mice, there was no effect of acute restraint on either LORE duration or BECRR. However, repeated restraint increased ethanol sensitivity at a 4.1g/kg dose; with an increase in LORE duration, but a decrease in BECRR. Differences in hypothalamic-pituitary-adrenal (HPA) axis responsiveness to restraint stress (as measured by plasma CORT) were also examined between genotypes. ILS mice displayed habituation to repeated restraint, whereas ISS mice did not. Lastly, the effect of enhanced CORT levels independent of psychological stress was examined for its effects on the sedative-hypnotic effects of ethanol. There were no effects of CORT pretreatment on LORE duration or BECRR in ILS mice compared to saline- or noninjected littermates. In contrast, ISS mice injected with CORT showed a decreased duration of LORE, but no effects on BECRR. These findings suggest that in addition to genetic susceptibility, environmental factors (e.g., restraint stress, exogenous CORT administration) also influence sensitivity to the sedative effects of ethanol through alteration of central nervous system sensitivity and pharmacokinetic parameters, and do so in a genotype-dependent manner.

Multiple ADH genes modulate risk for drug dependence in both African- and European-Americans

Drug dependence (DD) is commonly co-morbid with alcohol dependence (AD). Many studies have also shown common genetic risk factors for these disorders. We previously reported associations of AD with seven alcohol dehydrogenase (ADH) genes. The present study examines the relationship between these genes and DD. We genotyped 16 markers within the ADH gene cluster and 38 unlinked ancestry-informative markers in a case-control sample of 718 individuals. All markers were consistent with Hardy-Weinberg equilibrium in controls, but some markers showed Hardy-Weinberg disequilibrium in cases (minimal P = 0.002). Genotypes of many markers were associated with DD, both before and after controlling for admixture effects (minimal P < 1.0 x 10(-6)). Diplotype trend regression analysis showed that ADH5 and ADH6 genotypes, and diplotypes at ADH1A, ADH1B, ADH1C and ADH7 (minimal P = 0.002), were associated with DD in European-Americans and/or African-Americans. This first report of an allelic association of these loci with DD provides new insight into the mechanism of genetic risk for DD. These findings, obtained using a series of powerful and reliable analytic methods, may also help to explain the high rate of co-morbidity between AD and DD.