In particular, the rates of depression among adolescents have been rising in several high-income countries, with steeper increases observed among girls. This highlights the importance of understanding modifiable risk factors in order to inform primary prevention strategies.
Alcohol consumption among adolescents in most high-income countries has actually declined over the past two decades. However, this decrease in alcohol use has not resulted in a reduction in alcohol-related harms among young adults.
There is considerable variation in alcohol use patterns across countries, but in the UK, for example, there is a significant increase in alcohol use between the ages of 15 and 18, with limited evidence of gender differences. Subsequently, alcohol use stabilizes and even slightly decreases by the age of 22.
However, it is also possible that alcohol use precedes the development of depressive symptoms. Alcohol use can lead to adverse social, psychological, and physical outcomes, which in turn increase the risk of subsequent depression. The influence of different patterns of alcohol use on the risk of depression remains unclear and requires further investigation.
It is important to distinguish between alcohol consumption (frequency and quantity of use) and problem use or alcohol use disorders. Alcohol dependence, which is the most severe form of problem use, typically emerges around the age of 16. Compared to other excessive drinking behaviors, alcohol dependence may be particularly important as a risk factor for depression.
This suggests that alcohol dependence, but not high frequency or quantity of consumption, may increase the risk of subsequent depression, which has implications for public health interventions.
Most studies on the relationship between alcohol use and depression have been conducted in adults, with limited research specifically focusing on adolescents. Existing evidence from longitudinal studies suggests that alcohol use disorders, including dependence, increase the risk of subsequent depression.
However, the association with frequency and quantity of consumption appears to be confounded by other factors. Furthermore, the quality of these studies is often low, and their findings may not be generalizable to adolescents.
Studies on alcohol use and depression among adolescents have several limitations. Many of these studies were conducted in specific countries such as New Zealand or the USA, which limits their generalizability to other populations. Some studies relied on lifetime measures of alcohol misuse or dependence, which can introduce recall bias. Additionally, the quality of the studies is often low, with limited adjustments for pre-existing depression and potential confounders.
Another limitation is that most participants in these studies were born in the 1970s or early 1980s, and patterns of alcohol use have changed among young people since then. Therefore, evidence from more contemporary samples would provide valuable insights for future public health policies.
Few studies have specifically tested the hypothesis that alcohol dependence, but not consumption, during adolescence increases the risk of depression during young adulthood. Previous reviews have explored the potential influence of alcohol use severity on the associations with depression.
Some evidence suggests stronger associations between alcohol use disorders and depression compared to consumption alone. However, these reviews were often narrative and did not assess study quality adequately. More research is needed to examine the effects of alcohol dependence and consumption at different time points during adolescence and their potential implications for public health interventions.
The aim of this study was to examine changes in alcohol dependence from ages 16 to 23, a critical developmental period when average alcohol use increases rapidly. The researchers investigated whether higher levels of alcohol dependence at age 18 or a more rapid increase in dependence over a short period were associated with depression at age 24. They also examined alcohol consumption to test the hypothesis that dependence, but not consumption, increases the risk of subsequent depression.
The findings of the study indicate that alcohol dependence at age 18 is associated with depression at age 24. This association remained significant even when considering levels of alcohol dependence at each age from 17 to 22. On the other hand, there was no evidence of an association between frequency or quantity of alcohol consumption and depression.
These results suggest that high levels of alcohol consumption alone may not increase the risk of depression during young adulthood unless there are features of dependence involved. The study also found no evidence that a faster increase in levels of alcohol dependence across adolescence was associated with depression at age 24.
While this study provides valuable insights into the relationship between alcohol dependence and depression during adolescence and young adulthood, it also has several limitations. Attrition in the cohort from birth to age 24 was substantial, and the researchers used inverse probability weighting to address potential bias.
The sample was recruited from a specific UK region, and most participants were White, which limits the generalizability of the findings. Furthermore, the study did not directly compare dependence and consumption due to high correlations between linear slopes, and the possibility of statistical differences between the two cannot be ruled out.
The study also had limitations in terms of the measurement of alcohol consumption and dependence. Some features of alcohol abuse were excluded from the measures used, and frequency was not disaggregated from quantity of consumption. The study design did not allow for the assessment of time-varying confounders, such as depressive symptoms after age 16. Additionally, the study did not explore potential differences in the association between alcohol use and depression based on gender.
Despite these limitations, the findings of this study suggest that preventing alcohol dependence during adolescence or providing early treatment for dependence could reduce the risk of depression in young adulthood. High frequency and quantity of alcohol consumption should also be targeted during adolescence, as they are associated with injury and antisocial behavior.
Public health interventions aimed at preventing depression could focus on subthreshold dependence, which often involves high frequency and quantity of consumption. Psychosocial interventions and behavioral interventions targeting excessive alcohol use among adolescents have shown promise in reducing depressive symptoms. Additionally, interventions targeting young people who are dependent or at risk of alcohol dependence could be evaluated and implemented in various settings.
Chemical Implications:
Alcohol is a psychoactive substance that affects the central nervous system. When consumed, it enters the bloodstream and is distributed throughout the body, including the brain. Alcohol interacts with various neurotransmitters, including gamma-aminobutyric acid (GABA) and glutamate, resulting in sedative effects and the release of dopamine, which produces feelings of pleasure. However, chronic and excessive alcohol use can disrupt the delicate balance of neurotransmitters in the brain, leading to chemical imbalances that contribute to the development of mental health disorders, such as depression.
Hormonal Implications:
Alcohol dependence can also have significant implications for hormonal regulation in the body. Chronic alcohol use can disrupt the normal functioning of the hypothalamic-pituitary-adrenal (HPA) axis, which is responsible for regulating stress responses and hormone production. Alcohol abuse can lead to dysregulation of cortisol, a hormone involved in stress responses. Dysregulation of cortisol levels has been associated with an increased risk of developing depressive symptoms. Furthermore, alcohol can disrupt the production and regulation of other hormones, such as serotonin and norepinephrine, which play crucial roles in mood regulation and emotional well-being.
Brain Development Implications:
Adolescence and young adulthood are critical periods of brain development characterized by significant structural and functional changes. The brain undergoes maturation processes, particularly in regions associated with emotional regulation, impulse control, and decision-making. Alcohol use during this developmental stage can have detrimental effects on brain development. Studies have shown that alcohol consumption during adolescence can impair the normal development of the prefrontal cortex, which is responsible for executive functions, emotional regulation, and decision-making. These impairments can increase the susceptibility to developing mental health disorders, including depression.
Psychological Implications:
The link between alcohol dependence and depression is not solely based on chemical, hormonal, and brain development factors. Psychological factors also contribute to the association. Individuals with depression may turn to alcohol as a means of self-medication to cope with negative emotions and alleviate symptoms. However, this self-medication strategy is counterproductive, as alcohol is a depressant and can exacerbate depressive symptoms in the long term. Furthermore, alcohol dependence can lead to adverse social and psychological consequences, including strained relationships, social isolation, and low self-esteem, which can further contribute to the development or worsening of depressive symptoms.
In conclusion, this study contributes to our understanding of the relationship between alcohol use and depression during adolescence and young adulthood. The findings suggest that alcohol dependence during adolescence is associated with an increased risk of depression in young adulthood, while frequency and quantity of alcohol consumption alone may not significantly increase the risk.
These findings have important implications for public health interventions and highlight the need for further research to better understand the complex interplay between alcohol use and mental health outcomes in young people. By addressing these issues, we can develop more effective strategies to prevent and treat depression among adolescents and young adults.
