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Breaking Down Addiction Into Its Constituent Parts: Neuroscience, Incentive Salience, Environment, and Habits

Dr. Daniel H. Lende

Daniel Lende is an associate professor from the department of anthropology at The University of South Florida. He was trained in medical, psychological, and biological anthropology and public health at Emory University in Georgia. His research interests revolve around substance use and abuse, behavioral health, stress, cancer, post-traumatic stress disorder, embodiment, interventions in behavioral health, and risk-factor epidemiology. He has done fieldwork research in both Colombia and the United States. Dr. Lende and Dr. Downey (the other author of our class book) started Neuroanthropology, which is one of The Public Library of Science (PLOS) Blogs.

Addiction and Neuroanthropology

“Addiction and Neuroanthropology” by Daniel H. Lende is a multifaceted explanation of the neural and cultural processes intertwined in drug seeking behavior and addiction. A difference between Colombian ideologies of addiction and North American ideologies is that in Columbia, the problem of addiction doesn’t revolve around pleasure. In Columbia, addiction defies their basic social value, which is protecting family, friends, and the community. In this context, addiction is problematic because drug seeking and using surpasses basic social values. In the United States, however, pleasure is one of the main concerns about addiction. It is viewed as a disease that develops due to one’s biology and self-control. Lende uses both a combination of previous neuroscientific evidence in conjunction with his ethnographic fieldwork to explain how addiction is not a problem of pleasure or the self, but a neuroanthropological conglomerate of a host of factors.

Lende states that addiction is composed of two parts, the compulsive desire for a drug and the drug habit that is formed. Addiction, according to the Diagnostic and Statistical Manual (DSM) consists of four parts. The first criteria are that addiction involves the experiencing of tolerance and withdrawal. The second discusses how addiction also involves continued drug use despite their impact on health and one’s social life. The third further explains addiction as the persistent desire to use drugs after multiple failed attempts at controlling use. Lastly, the fourth criteria are about how drug use interferes with daily life and roles and obligations are neglected.

So, what drives the actual behaviors associated with addiction? The 1993 theory of addiction proposed by Robinson and Berridge claims that incentive salience is the reason for addiction. This theory led to widespread belief that the mesolimbic dopaminergic pathway was singlehandedly responsible. Lende proposes that this view of addiction is problematic and desire and involvement, or the cultural aspects of drug use, are a couple of the components missing from this explanation.

Neuroscience and Addiction

Previous studies have shown us that addiction involves many interconnected brain areas such as emotion, memory, and choice. Addiction encompasses the basal brain, which is involved in body regulation and activation, limbic circuits associated with emotions and environmental processing, and frontal cortices, which are associated with executive functions such as control, planning, and organization. The neuroscientific aspect of the pursuit of drugs and the repeated use of drugs involves two parts of the mesolimbic pathway, the ventral and dorsal striatum and the ventral tegmental area.

Incentive Salience and Addiction

Reward theory states that environmental stimuli shape animal responses. Berridge and Robinson believe that there are three facets to the reward process. The first is liking, or the hedonic impact, learning, or making predictive associations, and lastly, wanting, or incentive salience. Incentive salience is a type of “wanting” that involves goals, expectations, and future outcomes. Salience, however, is still not the complete picture because desire and involvement are both biological and cultural. Incentive salience is mediated by both the nucleus accumbens and the ventral pallidum. Furthermore, individual experiences, the presence of cues, social contexts, and environmental influences all produce different patterns of firing resulting in differences in salience signaling.

An example that provides a better understanding of the behavioral side of the explanation is adolescent drug use. Students with problems in their home life and academic problems at school see few options for fun, success, or a sense of involvement in either of these settings. When rewards from school and family are absent, these two contexts become irrelevant and lose their incentive salience, therefore, students seek other options and other realms where rewards are provided and incentive salience is present. As Berridge et al. (2009) would sum it up, incentive salience is about a subjective sense of “this matters,” rather than conscious desire. Incentive salience is about the motivation of drug seeking rather than the appreciation of wanting or desiring drugs.

Neuroscience and The Formation of Habits

Habits, as defined by Graybiel (2008), are “learned, repetitive, sequential, context-triggered behaviors performed not in relation to a current or future goal but rather in relation to a pervious goal and the antecedent behavior that most successfully led to achieving that goal.” Habits are a product of both behaviors and neurobiology.

Neurologically, learning about the rewards associated with drug use activates the ventral striatum. As drug use becomes persistent and repetitive, a neural activation shift takes place from the ventral striatum to the dorsal striatum, where activation here serves to maintain drug seeking and drug using habits. Due to this shift, the ventral striatum, which serves to evaluate outcomes and consequence of behaviors, no longer serves its function and behaviors are mechanically produced. Despite increased tolerance, habits mediated by the dorsal striatum become resistant to change regardless of the rewards reaped by that behavior.

An example of this is extinction training in lab rats. Rats trained to press a lever that delivers drugs exhibit neurobiologically mediated behaviors associated with the dorsal striatum. When placed in a different context where lever pressing does not yield drugs, rats continuously lever press although no drugs are administered. Only when the dorsal striatum or nucleus accumbens are lesioned do rat lever pressing behaviors cease.

Behavior and The Formation of Habits

This neurological explanation leads people to believe that addicts find little pleasure in continued drug use. However, behaviorally, drug use may still be a rewarding activity. The social interactions associated with drug use are rewarding despite the blunting of the pharmalogical effects of the drug. Once addiction sets in, oftentimes familial relationships and community involvement decreases and strong social bonds develop between drug users. Even without the same extent of high, the social networks formed with drug users become a major source of social interaction. Additionally, stress increases dorsal striatum activation which further reinforces habitual behaviors.

Summary

Drug use has more incentive salience than other areas of one’s life and becomes habitual. Increased drug use is reinforced because of social bonds between drug users, the neurological rewards associated with the high of the drug, and the activation of habit solidifying brain regions. The more involvement in drug social groups, the more incentive salience signaling increases and drug users seek drugs out even more. This complicated picture of drug use shows how addiction is both neurological and anthropological.

Similar Research

This chapter reminds me of our very first readings that discussed nerves, synapses, neurotransmitters, and different regions of the brain. It also reminds me of the second week’s readings about the encultured brain. Addiction is a perfect example of how the brain is encultured. This chapter shows how a neurological structure could influence behaviors and how an individual’s environment and behaviors also serve to reinforce neural activation patters and solidify these behaviors. This reading also reminded me of articles written by Dr. Gilbert Quintero, a cultural anthropologist who researches the social, cultural, and political economic aspects of drug use. Like Lende, Quintero has also studied young adult populations in the United States.

Towards the end of the chapter Lende touches on the idea of cultural models and how they play a role in the addiction process. If you all don’t already know, Dr. Bill Dressler, here in our very own anthropology department, conducts a lot of research on cultural models. His research focuses on how cultural consonance or discordance with salient cultural models may produce health benefits or may prove to be detrimental to one’s health. Next week’s reading on depression and anxiety discusses this concept further. People who are not culturally consonant with salient cultural models of a “good life” develop higher levels of anxiety than those who are culturally consonant. This relates to Dr. Lende’s argument because as we learned, higher levels of stress increase activation in the dorsal striatum. And as we know, the dorsal striatum serves to maintain and further perpetuate habits. Therefore, stress and anxiety associated with alienation from the community and family, coupled with societies’ negative view of addiction and the addict’s discordant lifestyle with salient cultural models, serve to dig a drug addict deeper into his or her drug pattern.

What I Liked or Didn’t Like

I liked how this chapter began by showing the contrasting ideologies behind addiction in Columbia and the United States. I also liked how the discussion progressed to an explanation of previous beliefs about drug use, addiction, and drug addicts. I believe that Lende’s approach of providing the reader with broader preconceived notions about addiction and his “busting” of these myths is an effective way to draw the reader in and provide alternate explanations. He talks about how historically, people have either taken a strictly neurological approach to addiction or a strictly behavioral approach to addiction. Then, he mends these two arguments by explaining how both are intertwined and are required for an accurate and holistic explanation of addiction.

What I thought was lacking was the organization of the chapter. I felt like there were certain areas that could be more condensed and straight to the point. I also felt that information that should have been presented together was scattered around which made it a little more difficult to grasp. This disorganization made the reader fetch for information and have to piece it all together for a comprehensive understanding. Similarly, I felt that a summary at the end of each section with the key take away points would have been beneficial to understanding how each component of the argument ties into the argument as a whole.

 

Questions for Pondering

  1. If the nucleus accumbens and the dorsal striatum are responsible for forming habitual drug seeking behaviors in addicts, why don’t we just lesion those brain areas?
  2. Why do you think that current drug rehab programs so often fail to change addictive behaviors?
  3. Using what Lende has shared with us, how could we use this knowledge to develop a more effective treatment process?
  4. Some children with negative home lives do not turn to drugs while others do. What do you think determines whether a child turns to drugs or not?
  5. Nature or nurture? Which do you think takes precedent in the context of addiction? Why?

Addiction and Neuroanthropology: Querer mas y mas

Daniel H. Lende

Colombian Study: Colombian perspective of addiction versus the perspective of the United States, the world’s largest consumer of drugs

According to the Colombians studied in Dr. Lende’s study, drug abuse involved wanting more and more (querer mas y mas), cravings, desire, and urges. Drug use was seen as a range from a small vice (everyone has some sort of vice) to the worst case scenario mode of putting individuals directly onto the street. The latter is  a complete violation of Colombian social norms because of the overarching desire for drugs more than the value of desire to be with family and friends. Drugs, especially cocaine (referred to as la droga), have the potential to violate one of the most entrenched values of Colombian culture–protecting the well-being of loved ones. When the desire for drugs outweighs the values, it becomes a problem, a habit that becomes hard to control. Otherwise, drug usage is not harshly judged unless it becomes a big enough problem that it dictates the individual.

In the United States, perspectives of drug use include viewing use as a moral failing, or a pathology. Americans have the tendency to compare drug use to either a biological pathology (chemical imbalances caused by drug use, “reward deficiency syndrome”) or a reflection of an individual’s self-control . The American perspective of drug use is Puritanistic, relating drug use to the “immoral” desire of too much pleasure.  According to the American perspective, the disruption of the hard-wired pleasure circuits already within the brain can be “hijacked” by this “immoral” drug usage.

By comparing these two starkly different views, Dr. Lende was able to collage emic and etic perspectives and the connection between behavior and experience, creating an ethnographic, neurological revelation regarding addiction:

Addiction is a problem of involvement, not just pleasure or of the self.

So, how does neuroanthropology play a role in all of this? 

Lende identified two core components of addiction and addictive behavior directly from individuals experienced to study: users report compulsive desires and urges for drugs, leading to relapse or excess; users also identified drug use as an escape from the doldrums and stresses of every day life. Furthermore, Lende identified that sociocultural dynamics affect an individual’s cues and habits that create compulsive or destructive ends. According to the DSM, criteria for substance abuse requires the specific pharmacological structure and mechanism of the drug, whether or not individuals demonstrate tolerance or withdrawal, continued use despite negative effects, and using increasingly higher dosages to achieve greater effects. The problem, which the neuroanthropological view seeks to tackle, peaks when many drugs produce no physiological adaptations. How does one measure the extent of substance abuse according to the DSM’s guidelines if no physiological symptoms are expressed? Causation for addiction must be reviewed, according to Lende, in order to go beyond focusing on withdrawal. According to Lende:

“A full explanation for addiction is not to be found in deviations from rational choice, leaving out community dynamics, social meanings, and other important aspects of substance abuse. Morevoer, this approach also treats addiction as solely an individual problem, in particular, by assuming that addiction is a brain disease that limits the mind’s ability to lead a rational life. “

The aforementioned approach of treating addiction as a disease foregoes answering WHY. What drove this individual to substance abuse? Why did can it become so destructive for particular individuals? These questions, according to Lende, need to be examined in order to garner a full understanding of addiction.

Neuroscience and Addiction

Addiction is a complex process that incorporates many different parts of the brain, rather than just a few isolated sections. Motor, sensory, and bodily regulation must be integrated together before addiction can occur. It begins from the basal parts of the brain (regulation, activation of bodily functions), runs through the limbic system (emotions, evaluation of stimuli), up through the frontal cortices (higher-order cognition). As Lende put it, they have to do with what to do, when to do, and how much to do.

Wanting More and More: The Neuroanthropology of Involvement

Incentive salience, or the determination of which incentives for reward are most important (salient) to an individual, was proposed in a 1993 study as the core psychobiological process that is most affected in continued substance abuse. The biochemical mediator for incentive salience is the dopaminergic system. In Lende’s studies in Colombia, he found that using incentive salience as a model for a scale depicting experience turned out to be a good predictor of addicted status. Asking real people about their real experiences with drug use, Lende sought to better understand their want for drugs and how they would get drugs, and how they felt before actually getting the drugs. In the end, he found that the “want” actually corresponded to experiences during the drug use rather than before or after, and that meaning and social context played a role in the experience.

Incentive Salience and Addiction: Mediation, Environment, and Anthropology 

According to Lende, incentive salience is a much more focused means of examining drug usage. Incentive salience merely reflects a few aspects of addiction (remember, addiction is highly complex and dynamic), and does provide good insight into addiction, but does not fully explain it. Incentive salience gives researchers an insight into the neurological processes of decision making, and the means of seeking out rewards. It also links together cues and rewards through motivation and action.

Incentive salience, however, is not the same thing as conscious desire. As Lende puts it:

That urge for pizza people get, that sense that they want it now, and that they just have to have it–that is incentive salience.

Well, now I want some pizza. Thanks, Dr. Lende.

Anyways, a good way to garner information regarding incentive salience has to do with ethnographical research. In his Colombia study, Lende asked participants to describe a “typical day”. His results”

  • Heavy drug users described a sequence of feeling ambivalent towards drug use, a marked decision to use, and then the action of seeking out whatever drug they use. In addition, these people reported a stronger urgency and desire to use once the decision to use had been made. They reported that they felt the want for more and more (querer mas y mas) in the moment. Not before, not after, but in the moment that the drug use was happening.

^^^that’s incentive salience

The salience experienced by Colombian users, however, occurred when using that drug transformed their lives. It took them away from day to day life experiences, the monotonous, and created a  viaje (journey) to the sublime. Well, who wouldn’t want that?

According to Lende, “signals for salience depend on the presence of cues, the structure of environments, and present and past states. In other words, when behavioral options are salient, animals will pursue them–that is what incentive salience does.”

This incentive salience can be applied in two ways:

1. Involvement: the creation of a feeling of belonging or involvement in cultural meaning schema

2. Transition: Signaling transitions between activities, shifting involvement from what matters throughout the day

 

Yet, how does this explain habitual use? Incentive salience alone just doesn’t cut it. Habits play a role in the same neurological processes that incentive salience does. When the want for more and more (querer mas y mas) becomes a cultural commodity, partnering alongside feelings of belonging and transcendence from the mundane, that may lead people to wanting to repeat that experience. Repetition over continual, extended periods of time can create a habit. A habit (referenced in the text, Gaybriel 2008, p.363) is defined as:

“learned, repetitive, sequential, context-triggered behaviors which are performed not in relation to the current or future goal but rather in relation to a previous goal and the antecedent behavior that most successfully led to achieving that goal.”

Lende goes on to describe the interworkings of habits and culture, pointing out that the neuroanthropological approach sheds light into the social and biological aspects of drug use. In the end, the neuroanthropological approach helps better understand the complexity and dynamics of addiction.