Age-Related Differences in Alcohol Intake and Control Over Alcohol Seeking in Rats

Abstract

Alcohol use disorder (AUD) is characterized by excessive and persistent alcohol use, despite adverse consequences. AUD often originates during adolescence, as do other substance use disorders. However, despite periods of excessive alcohol intake, many adolescents reduce their alcohol use by early adulthood. Brain development, social context, personality traits, and genetic makeup are thought to play an important role in these age-dependent fluctuations in alcohol use. However, studies that directly investigate age-related differences in the effects of alcohol exposure on brain and behavior are sparse. Therefore, to better understand the relationship between adolescent alcohol consumption and AUD-like behavior, this study compared the degree of control over alcohol seeking in rats that differed in terms of age of onset of alcohol drinking and in their level of alcohol consumption. We hypothesized that control over alcohol seeking is more prominent in adolescent-onset rats than in adult-onset rats, and that control over alcohol seeking is related to the consumed amount of alcohol. To test this hypothesis, alcohol seeking in the presence of a conditioned aversive stimulus was assessed after 2 months of intermittent alcohol access (IAA) in rats that consumed alcohol from postnatal day 42 (adolescence) or day 77 (adulthood). The rats were subdivided into low (LD), medium (MD), or high (HD) alcohol drinking rats, in order to assess the impact of the extent of alcohol intake on control over alcohol seeking. The adolescent-onset animals consumed slightly, but significantly less alcohol compared to the adult-onset rats. In adult-onset rats, we found that conditioned suppression of alcohol seeking, i.e., reduction of alcohol seeking by presentation of a conditioned aversive stimulus, was most pronounced in LD. By contrast, in the adolescent-onset rats, MD and HD showed increased alcohol seeking compared to LD, which was suppressed by conditioned aversive stimuli. Taken together, these findings reveal a complex relationship between the age of onset and level of alcohol intake with control over alcohol seeking, whereby adolescent rats consume less alcohol than adults. In adult rats, control over alcohol seeking is negatively related to preceding levels of alcohol intake. By contrast, adolescent rats appear to retain control over alcohol seeking, even after a history of high levels of alcohol intake.

Motivational and Control Mechanisms Underlying Adolescent versus Adult Alcohol Use

“…While human studies investigating the role of age in the relation between alcohol use and cognitive control are missing, there is evidence from rodent studies to suggest that adolescent compared to adult onset drinkers experience stronger reductions in cognitive control-related functions (for reviews see [49,50]), including more extensive prefrontal cortex damage [51] and increases in impulsive decision making [52]. Moreover, adolescent animals appear less prone to withdrawal [53], and yet also less prone to tolerance [54], impairments in behavioral flexibility [55], and for loss of control over alcohol use [56]. These findings highlight the complex relationship between adolescent alcohol exposure and AUD-like behaviors in later life; exposure to alcohol during adolescence may render individuals more sensitive to some effects of alcohol, but less sensitive to others.…”

Influence of Age and Genetic Background on Ethanol Intake and Behavioral Response Following Ethanol Consumption and During Abstinence in a Model of Alcohol Abuse

“…Indeed, even if human studies suggest that age of onset of alcohol use is associated with the risk to develop AUD later in life, recent systematic reviews suggest that this association is less consistent and might be driven by confounding factors, such as the history of alcohol problems in the family, preceding mental health problems, socioeconomic status, or genetic background ( Maimaris and McCambridge, 2014 ; Marshall, 2014 ; Kuntsche et al, 2016 ). Even animal studies on this issue are not always consistent ( Labots et al, 2018 ; Spear, 2018 ; Towner and Varlinskaya, 2020 ; Mugantseva et al, 2021 ) and therefore, further investigation is needed to help in clarifying the role of causality between early alcohol onset and increased risk of later AUD.…”

Perceived Social Discrimination, Socioeconomic Status, and Alcohol Consumption among Chinese Adults: A Nationally Representative Study

“…Individual differences are also an important factor in drinking behavior. Common personal factors related to drinking include gender, age, ethnicity, education level, and marital status [ 30 , 31 , 32 , 33 ]. In terms of geographic area of residence, several studies have pointed out that it has little effect on drinking behavior [ 34 ].…”