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For example, in rats, exposure to alcohol during adolescence increases risky or impulsive decision-making in adulthood [108]. These findings suggest that if adolescents consume alcohol, such consumption may lead to tendencies promoting alcohol consumption, generating a vicious cycle of addictive behavior. Thus, at this point in time, it is important to be cautious about inferring causality, particularly as many human studies involve associational rather than longitudinal designs.
Social norms, availability, accessibility, legality, modeling, expectancies, societal approval, visibility, targeting practices, and cultural beliefs all influence the experience of addiction. An individual exposed to drug use at an early age can be influenced by social modeling (or learning via observation). Additionally, certain environments have specific social norms related to drug use (e.g., “Everyone experiments a little with drugs in college”). For example, researchers have found a robust association between trauma and addiction (Dube et al., 2002, 2003; Giordano et al., 2016). Indeed, in the original Adverse Childhood Experiences (ACEs) study, Felitti et al. (1998) found that more ACEs increased the odds of subsequent drug and alcohol use. One explanation for this trend is that the toxic stress from trauma leads to a dysregulated stress response.
Genetic and Biological Approaches to Addiction
Understanding the neurobiological changes that the brain undergoes has allowed for developments of novel intervention and prevention methods, while also providing overall stigma reduction. Continued advances in neuroscience research will serve to provide new and effective ways to combat the disease of substance use disorders. In addition, investigators are concerned about the effects of exposure during adolescence and early adulthood. All of the evidence suggests that the earlier a person begins using alcohol or other substances, the greater the likelihood of eventually developing a substance use disorder, because of the interaction between exposure and these brain changes at a critical developmental point. Finally, consider the fact that a person’s overall health and development may be affected by poor nutrition, physical trauma or injury, or exposure to diseases that often accompany substance misuse. Like diabetes, cancer and heart disease, addiction is caused by a combination of factors.
- There is a freedom of choice, yet there is a shift of prevailing choices that nevertheless can kill.
- Epigenetics is the theory that gene expression is altered by environmental events through three main mechanisms – DNA methylation, histone acetylation, non-coding RNA – and that these changes become heritable despite no specific changes in DNA sequences.
- Across the globe, those that tended to have a higher prevalence of substance dependence were in their twenties, unemployed, and male.
- In fact, as shown by the studies correlating dopamine receptors with social experience, imaging is capable of capturing the impact of the social environment on brain function.
- Thus, these folks would be at greater risk for developing an addiction because of their genetic vulnerability.
As in adults, other considerations (e.g., co-occurring disorders and after-care) are important in the treatment of adolescent addictions [194, 195]. Such interactions appear to have important clinical implications with respect to addictive behaviors in adolescents; for example, greater stress-induced risk-taking has been linked to poorer treatment outcome in adolescent smokers sober house [168]. For alcohol addiction, meta-analysis of twin and adoption studies has estimated heritability at ~50%, while estimates for opioid addiction are even higher [44, 45]. It has been argued that a genetic contribution cannot support a disease view of a behavior, because most behavioral traits, including religious and political inclinations, have a genetic contribution [4].
Genetics of addiction
In recent years, the conceptualization of addiction as a brain disease has come under increasing criticism. When first put forward, the brain disease view was mainly an attempt to articulate an effective response to prevailing nonscientific, moralizing, and stigmatizing attitudes to addiction. According to these attitudes, addiction was simply the result of a person’s moral failing or weakness of character, rather than a “real” disease [3]. To promote patient access to treatments, scientists needed to argue that there is a biological basis beneath the challenging behaviors of individuals suffering from addiction. This argument was particularly targeted to the public, policymakers and health care professionals, many of whom held that since addiction was a misery people brought upon themselves, it fell beyond the scope of medicine, and was neither amenable to treatment, nor warranted the use of taxpayer money. A secondary motivational neurocircuitry has been proposed to explain how other brain circuits may influence motivational decision-making processes and behaviors within the primary circuitry [50].
For designing policies, such as taxation and regulation of access, economics and public administration provide the most pertinent perspectives, but these also benefit from biological and behavioral science insights. A common criticism of the notion that addiction is a brain disease is that it is reductionist and in the end therefore deterministic [81, 82]. As indicated above, viewing addiction as a brain disease simply states that neurobiology is an undeniable component of addiction. A reason for deterministic interpretations may be that modern neuroscience emphasizes an understanding of proximal causality within research designs (e.g., whether an observed link between biological processes is mediated by a specific mechanism). That does not in any way reflect a superordinate assumption that neuroscience will achieve global causality. On the contrary, since we realize that addiction involves interactions between biology, environment and society, ultimate (complete) prediction of behavior based on an understanding of neural processes alone is neither expected, nor a goal.