Ch 1: Introduction to Biological Models of Addiction Theories and Biological Basis of Addiction

There is a freedom of choice, yet there is a shift of prevailing choices that nevertheless can kill. In dismissing the relevance of genetic risk for addiction, Hall writes that “a large number of alleles are involved in the genetic susceptibility to addiction and individually these alleles might very weakly predict a risk of addiction”. He goes on to conclude that “generally, genetic prediction of the risk of disease (even with whole-genome sequencing data) is unlikely to be informative for most people who have a so-called average risk of developing an addiction disorder” [7].

• Genome-wide association studies of complex traits have largely confirmed the century old “infinitisemal model” in which Fisher reconciled Mendelian and polygenic traits [51].
• Furthermore, dependence rates were greater in unemployed populations ages 18 and older and in metropolitan-residing populations ages 12 and older.
• This means that, while biology is necessary for drug-use problems to develop (if your brain doesn’t react to a drug, you will not become addicted to it), it is not sufficient to explain them.
• 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].

Biological Research on Addiction is one of three volumes comprising the 2,500-page series, Comprehensive Addictive Behaviors and Disorders. This series provides the most complete collection of current knowledge on addictive behaviors and disorders to date. When surveying populations based on gender in those ages 12 and older, it was observed that males had a higher substance dependence rate than females. Drug and Alcohol Dependence reports that older adults abuse drugs including alcohol at a rate of 15–20%. Other research has pointed to people predisposed to alcohol addiction showcasing fewer, or different, biological signals letting them know that it’s time to stop drinking. And still, other reports have found a link between the tendency to develop alcohol use disorder and the levels of the mood regulator serotonin found or created in the body.

Mental Health Services

His research has established that drug- and stress-induced changes in genetic transcription factors and chromatin remodeling mechanisms in reward pathways mediate long-lived behavioral changes relevant to addiction and depression. Drug addiction is a complex, neurobehavioural process that subverts and alters primitive brain reward system circuits that are otherwise in place to help organisms survive. Substances of abuse are potent stimuli that encode enduring patterns of drug-seeking behaviour in the reward system. Brief, high-intensity reward activation is followed by a period of reduced activity and responsiveness, during which natural rewards are not strong enough to activate the system. At the same time, altered gene transcription results in the accumulation of long-lived intracellular proteins that sensitize the reward system.

These spontaneous remission rates are argued to invalidate the concept of a chronic, relapsing disease [4]. The age when one begins drinking or using a drug is another biological condition that can play a massive part in developing addictive behaviors. Introducing it to a mind-altering substance during this time could affect neurological pathways, making a person that much more susceptible to the possibility of long-term drug and alcohol abuse.

How substance use changes the brain

Others argue that addiction is not a disease because some people with addiction get better without treatment. People with the most serious form of SUD usually need intensive treatment followed by lifelong management of the disease. However, some people experiencing addiction stop drinking or using other substances without treatment. Others achieve recovery by attending self-help meetings without receiving much, if any, professional treatment. With the help and support of family, friends and peers to access help and stay in treatment, people struggling with a substance use disorder can increase their chances of recovery and survival.

• It does this by switching on brain circuits that make you feel wonderful, which then motivates you to repeat those behaviors.
• Based upon representative samples of the U.S. youth population in 2011, the lifetime prevalence of addictions to alcohol and illicit drugs has been estimated to be approximately 8% and 2%-3%, respectively.
• At Nova Recovery Center, Houston we provide our patients with a very comfortable detox process, where medical professionals provide monitoring and care around the clock.
• People with a substance use disorder can still reduce their use or abstain — it’s just much harder than it is for others.

Behaviorists explain drug use and addiction by emphasizing the way that these behaviors are learned or habitualized. According to social learning theory, which holds that behaviors are learned through imitating and observing others, someone might be peer pressured into trying drugs for the first time. Operant conditioning, which emphasizes repeating behaviors that result in a reward, may explain why an individual would seek out a “high” or the reduction in stress they may get from using a drug.

Genetic and Biological Approaches to Addiction

The individual’s drug of choice is determined through experimentation, whereby the interaction of the main effects of the drug, the individual’s inner psychological turmoil, and underlying personality traits identify the drug that produces the desired effects. The general classes of epigenetic alterations that have been implicated in transgenerational epigenetic inheritance include DNA mythylation, histone modifcations, and downregulation or upregulation of microRNAs. With respect to addiction, more research is needed to determine the specific heritable epigenetic alterations that arise from various forms of addiction in humans and the corresponding behavioral phenotypes from these epigenetic alterations that occur in human offspring. More generally, the heritable behavioral phenotypes that are derived from addiction-induced epigenetic alterations and transmitted from parent to offspring may serve to either increase or decrease the offspring’s risk of developing an addiction.

• It is not trivial to delineate the exact category of harmful substance use for which a label such as addiction is warranted (See Box 1).
• In addiction research, it’s believed that people misuse alcohol and drugs because of the the chemical reactions these produce in the brain.
• The multifaceted disorder needs a multifaceted conceptualization, and we find that in the biopsychosocial model of addiction (Marlatt & Baer, 1988).

It explains how these changes create a compulsion to continue using substances, regardless of the consequences. The sober house is used to explain why some people become addicted to certain substances, while others use the same substances but do not become addicted. This model demonstrates how addiction is seen as a disease that impacts each individual differently. It’s based on an understanding of how drugs work in the brain, along with an awareness of the genetic and environmental factors that affect each individual’s experience with addiction.

Chronic and relapsing, developmentally-limited, or spontaneously remitting?

Consistent with a role for rewarding effects of drugs in addictive processes and a role for dopamine in this process, an incentive salience model of drug addiction proposes that “liking” a drug may be separated from “wanting” [42, 43]. Another reward-based model suggests a “reward deficiency syndrome” in which individuals with addictions seek out and engage in addictive behaviors to compensate for hypo-functioning reward signals in the mesolimbic dopamine pathway [44]. In contrast to the incentive salience model, the reward deficiency model may be particularly relevant to self-medication theories of addiction [45, 46]. Over the past several decades, substantial research has investigated the biological factors leading to and resulting from addictions [1, 2].

Consistently, prefrontal cortical brain regions like the inferior frontal gyrus are amongst those most frequently implicated in studies of impaired impulse control [81] as well as in the control of craving or desire [66, 67]. Taken together, adolescents may not be able to regulate emotional or motivational states to the same degree as adults given their neurodevelopmental status. Given the relative immaturity in adolescents of brain regions like the prefrontal cortex involved in emotional and motivational processing including in the regulation of craving for drugs and food [66, 67], adolescents may be biologically vulnerable to engagement in addictive behaviors. Consistent with this notion, adolescents show largely subcortical/limbic responses to favorite food cues and individualized stress cues [68], whereas adults show both subcortical/limbic and prefrontal cortical responses [69, 70].

Some people may have a deficiency in their capacity to resist certain types of impulses. Thus, these folks would be at greater risk for developing an addiction because of their genetic vulnerability. You may have a genetic predisposition to develop addictive behaviors, but you don’t have to be born with specific genes to fall prey to drug or alcohol abuse. You may grow up in a chaotic household where drinking and doing drugs is modeled by your caregivers, but you might use that example to resist creating addictive cycles. And even mental health disorders can create different biological conditions that may affect one’s tendency to pick up addictive behaviors.