Social consequences of ethanol: Impact of age, stress, and prior history of ethanol exposure

Abstract

The adolescent period is associated with high significance of interactions with peers, high frequency of stressful situations, and high rates of alcohol use. At least two desired effects of alcohol that may contribute to heavy and problematic drinking during adolescence are its abilities to both facilitate interactions with peers and to alleviate anxiety, perhaps especially anxiety seen in social contexts. Ethanol-induced social facilitation can be seen using a simple model of adolescence in the rat, with normal adolescents, but not their more mature counterparts, demonstrating this ethanol-related social facilitation. Prior repeated stress induces expression of ethanol-induced social facilitation in adults and further enhances socially facilitating effects of ethanol among adolescent rats. In contrast, under normal circumstances, adolescent rats are less sensitive than adults to the social inhibition induced by higher ethanol doses and are insensitive to the socially anxiolytic effects of ethanol. Sensitivity to the socially anxiolytic effects of ethanol can be modified by prior stress or ethanol exposure at both ages. Shortly following repeated restraint or ethanol exposure, adolescents exhibit social anxiety-like behavior, indexed by reduced social preference, and enhanced sensitivity to the socially anxiolytic effects of ethanol, indexed through ethanol-associated reinstatement of social preference in these adolescents. Repeated restraint, but not repeated ethanol, induces similar effects in adults as well, eliciting social anxiety-like behavior and increasing their sensitivity to the socially anxiolytic effects of acute ethanol; the stressor also decreases sensitivity of adults to ethanol-induced social inhibition. The persisting consequences of early adolescent ethanol exposure differ from its immediate consequences, with males exposed early in adolescence, but not females or those exposed later in adolescence, showing social anxiety-like behavior when tested in adulthood. Adult males exposed to ethanol early in adolescence also show enhanced sensitivity to the socially facilitating effects of ethanol, whereas adult males exposed to ethanol during late adolescence demonstrate insensitivity to the socially suppressing effects of ethanol. To the extent that these results are applicable to humans, stressful live events may make alcohol more attractive for stressed adolescents and adults due to its socially facilitating and socially anxiolytic properties, therefore fostering high levels of drinking. Retention of adolescent-typical responsiveness to alcohol in adult males following adolescent alcohol exposure, including enhanced sensitivity to the socially facilitating effects of ethanol following early exposure and insensitivity to the socially inhibiting effects following late adolescent exposure, may put these males at risk for the development of alcohol-related disorders later in life.

Sex differences in alcohol self-administration and relapse-like behavior in Long-Evans rats

“…One of the consistent findings throughout these experiments was that while males showed greater alcohol-reinforced responding than females during self-administration sessions, females showed similar or greater alcohol intake (g/kg) than males. This finding is supported by several studies of alcohol consumption in outbred rat strains (Long-Evans, Wistar, Wistar Kyoto, Sprague-Dawley) in which males and females have been shown to consume similar amounts of alcohol (Schramm-Sapyta et al 2014; van Haaren and Anderson 1994; Varlinskaya and Spear 2015) or females consume more alcohol than males (Almeida et al 1998; Cailhol and Mormede 2001; Juarez and Barrios de Tomasi 1999; Lancaster and Spiegel 1992; Vetter-O’Hagen et al 2009). Moreover, similar levels of alcohol intake between males and females have been observed previously in P-rats and Long-Evans (Moore and Lynch 2015; Priddy et al 2017).…”

Chronic intermittent ethanol exposure during adolescence: Effects on stress-induced social alterations and social drinking in adulthood

“…These BECs are in the range of those produced by ethanol doses inducing social facilitation after i.p. administration (i.e., ~ 40 to 80 mg/dl; see Varlinskaya & Spear, 2002, 2015). It is tempting to speculate from these findings that AIE males, as well as stressed water-exposed males may modulate and limit their ethanol intake to achieve ethanol levels optimal for experiencing the socially facilitating effects of ethanol.…”

Consequences of adolescent use of alcohol and other drugs: Studies using rodent models

“…Depressive-like signs have emerged when indexed via decreases in sucrose consumption (used as a measure of anhedonia) or increased immobility in the Porsolt swim test (Slawecki et al, 2004; Ehlers et al, 2011; Briones & Woods, 2013). Reliable increases in social anxiety have been observed in adult males after EtOH exposure during early/mid adolescence, an effect that is sex-specific and not evident in females (Varlinskaya et al, 2014; Varlinskaya & Spear, 2015). Increases in general anxiety indexed via decreased open arm time in the elevated plus maze [EPM] (Slawecki et al, 2004; Montesinos et al, 2015a; Pandey et al, 2015) or increased defecation when in a novel environment (Popović et al, 2004) have also been reported in male rats, although these effects are not ubiquitous (Ehlers et al, 2011; Gilpin et al, 2012; Quoilin et al, 2012; White et al, 2000).…”