Early life temperamental anxiety is associated with excessive alcohol intake in adolescence: A rhesus monkey (Macaca mulatta) model.

Teenage alcohol abuse is a major health concern, particularly because the majority of alcohol consumed by teenagers is via binge drinking, a known risk factor for increasing the likelihood for the development of future alcohol use disorders (AUDs). Identifying individuals at risk for excessive alcohol intake in adolescence is a step toward developing effective preventative measures and intervention programs. As adults with AUDs tend to self-medicate their anxiety with alcohol, this longitudinal study assesses the role of infant anxiety-like temperament in the development of adolescent alcohol abuse using a nonhuman primate model. From birth until they were 5 months of age, behaviors of 64 rhesus monkeys (Macaca mulatta) were coded twice a week using an objective mother-infant scoring system that included behaviors traditionally used to assess anxiety and fearfulness in rhesus monkeys. When subjects were four months old, plasma cortisol was obtained. When subjects were adolescents (Mage = 44.88 months), another plasma cortisol sample was obtained about one month prior to allowing them unfettered access to an 8.4% (v/v) aspartame-sweetened alcohol solution for one hour a day over five-to-seven weeks. Results showed that behavioral indications of anxiety-like temperament in infancy, including high levels of mother-infant mutual ventral contact, low levels of environmental exploration, and low levels of interactions with peers were predictive of high adolescent alcohol intake (ie, drinking to intoxication). Plasma cortisol levels in infancy were positively correlated with plasma cortisol in adolescence, and both were positively correlated with high adolescent alcohol intake. Our findings indicate that high levels of traditional anxiety-like behaviors measured in the context of mother-infant interactions, coupled with high infant and adolescent plasma cortisol, are associated with binge-like high alcohol intake in adolescence, suggesting that individuals at risk for developing an AUD later in life may be determined, at least in part, by assessing their physiological and behavioral propensity for anxiety early in life.

Prevention of postpartum methamphetamine use with micronized progesterone trial (PROMPT): A pilot randomized controlled trial protocol.

Background: While most pregnant individuals with methamphetamine use disorder (MUD) achieve abstinence, the postpartum period remains a vulnerable time for return to methamphetamine use (MU). Promising data from human and animal models, including three randomized controlled trials, suggest that micronized progesterone may prevent postpartum return to cocaine and nicotine use by reducing cravings. The primary objective of this study is to assess feasibility of enrollment and randomization of postpartum individuals with MUD to micronized progesterone to prevent return to MU. The secondary objectives are to evaluate safety, establish a preliminary estimate of efficacy, and characterize the association between allopregnanolone levels and methamphetamine cravings. Methods: This is a pilot double-blind placebo randomized controlled trial. We plan to enroll 40 postpartum individuals with MUD over 24-months. Individuals, stratified by opioid use disorder (OUD), are randomized 1:1-400 mg oral micronized progesterone daily or placebo and attend weekly study sessions for 12 weeks. Feasibility is measured by achieving 80 % of enrollment goal. Safety is evaluated by side effect frequency, mental health status changes, lactation and medical complications. Efficacy is assessed by comparing proportion of participants with return to MU and time to return to MU based on self-report or urine testing between treatment and control groups. Salivary allopregnanolone levels and methamphetamine cravings are compared between the groups. Conclusion: Study results will provide a first critical step towards potential intervention for prevention of return to MU among postpartum individuals. Completion of this trial will set the stage for a large-scale efficacy trial.

Masculinized Second-to-Fourth Digit Ratio (2D:4D Ratio) Is Associated With Lower Cortisol Response in Infant Female Rhesus Monkeys (Macaca mulatta).

The second-to-fourth digit ratio (2D:4D ratio) is considered a postnatal proxy measure for the degree of prenatal androgen exposure (PAE), which is the primary factor responsible for masculinizing the brain of a developing fetus. Some studies suggest that the organizational effects of PAE may extend to the hypothalamic-pituitary-adrenal (HPA) axis response to stress. This study investigates the relationship between 2D:4D ratio and HPA axis functioning using a rhesus monkey (Macaca mulatta) model. Subjects were N = 268 (180 females, 88 males) rhesus monkey infants (3-4 months of age). Plasma cortisol concentrations were assayed from two blood samples obtained during a 25-h experimental social separation stressor at 2- and 7-h post-separation. Subjects' 2D:4D ratio was measured later in life (M age = 6.70 years). It was hypothesized that infant rhesus monkeys that exhibited a more masculine-like 2D:4D ratio would show lower levels of circulating cortisol after a social separation and relocation stressor. The results showed that there was a sex difference in the left-hand 2D:4D ratio. The results also showed that there was an overall sex difference in cortisol concentrations and that female, but not male, monkeys that exhibited a more masculine-like right- and left-hand 2D:4D ratio exhibited lower mean stress-induced cortisol concentrations early in life. These findings suggest that higher levels of prenatal androgens in females, as measured by 2D:4D ratio, may be related to an attenuated HPA axis stress-response, as measured by plasma cortisol levels. To the extent that these findings generalize to humans, they suggest that the organizational effects of PAE extend to the infant HPA axis, modulating the HPA axis response, particularly in females.