← In the Realm of Hungry Ghosts Close Encounters with Addiction
In the Realm of Hungry Ghosts Close Encounters with Addiction Chapter 16. Like a Child Not Released
Author: Gabor Mate Publisher: Berkeley, CA: North Atlantic Books. Publish Date: 2010-1-5 Review Date: Status:💥
Annotations
211
We’ve already seen that the brain circuits of motivation and of reward are recruited to serve addictive behaviors. In this chapter we’ll consider scientific evidence suggesting that addiction also disrupts the self-regulation circuits—which the addict needs in order to choose not to be an addict.
212
As with motor activities, we’ve discovered which parts of the brain are responsible for volition and choice by studying people whose brains have been injured. When certain brain areas are damaged, there are predictable patterns of impaired rational decision making and diminished impulse regulation. Brain-imaging studies and psychological testing indicate that the same areas are also impaired in drug addiction. And what is the result? If it wasn’t enough that powerful incentive and reward mechanisms drive the craving for drugs, on top of that the circuits that could normally inhibit and control those mechanisms are not up to their task. In fact, they are complicit in the addiction process. A double whammy: the watchman is aiding the thieves.
213
In general, the higher in the brain we ascend physically, the more recent are the brain centers in evolutionary development and the more complex their functions. In the brain stem, automatic functions such as breathing and body temperature are regulated; the emotional circuits are higher up; and at the very top surface of the brain is the cortex, or gray matter. None of these areas works on its own; all are in constant communication with other circuits near and far, and all are influenced by chemical messengers from elsewhere in the body and brain. As a human being matures, higher brain systems come to exert some control over the lower ones.
213
“Cortex” means bark, and the multilayered cerebral cortex envelops the rest of the brain like the bark of a tree. About the size and thickness of a table napkin, it contains the cell bodies of neurons organized into many essential centers, each with highly specialized functions. The visual cortex, for example, is in the occipital lobe at the back of the brain. If it sustains damage, as in the case of a stroke, vision is lost. The most recently evolved part of the cortex, distinguishing us from other animals, is the prefrontal cortex, the gray matter area in the front of the brain.
214
It’s a simplification, but an accurate one, to say that the frontal cortex—and particularly its prefrontal portions—acts as the chief executive officer of the brain. It is here that alternatives are weighed and choices considered. It is also here that emotionally driven impulses to act are evaluated and either given permission to go ahead or—if necessary—inhibited. One of the most important duties of the cortex is “to inhibit inappropriate response rather than to produce the appropriate one,” suggests neuropsychologist Joseph LeDoux.2 The prefrontal cortex (PFC), writes psychiatrist Jeffrey Schwartz, “plays a central role in the seemingly free selection of behaviors” by inhibiting many of the alternative responses that arise in a situation and allowing only one to proceed. “It makes sense, then, that when this region is damaged patients become unable to stifle inappropriate responses to their environment.”3 In other words, people with impaired PFC function will have poor impulse control and will behave in ways that to others seem uncalled for, childish, or bizarre.
-
N. D. Volkow and T.-?. Li, “Drug Addiction: The Neurobiology of Behavior Gone Awry,” Neuroscience 5 (December 2004): 963–70.
-
Joseph LeDoux, The Emotional Brain: The Mysterious Underpinnings of Emotional Life (New York: Simon & Schuster, 1996), 165.
214
It is also in the frontal cortex that social behaviors are learned. When the executive parts of the cortex have been destroyed in rats, they are still able to function—but only as immature youngsters who haven’t acquired any social skills. They are impulsive, aggressive, and sexually inappropriate. They behave very much like rats reared in isolation with no access to social play and other interactions.4 Monkeys injured in the area of the right PFC lose interactive skills such as the reading of emotional cues and the mutual grooming necessary for normal social contact. They soon come to be ostracized by their fellows. Human beings with prefrontal injuries also lose many of their social capacities. Here in the PFC important nerve systems are implicated in addiction.
- S. Pellis et al., “The Role of the Cortex in Play Fighting by Rats: Developmental and Evolutionary Implications,” Brain, Behavior, and Evolution 39 (1992): 270–84, quoted in Gordon M. Burghardt, “Play: Attributes and Neural Substrates,” in Handbook of Behavioral Neurobiology, vol. 13, ed. E. Blass (New York: Plenum Publishers, 2001), 388.
215
The executive functions of the PFC are not restricted to any one area, and its proper workings depend on healthy connections and input from the emotional, or limbic, centers in lower parts of the brain. Conversely, dysfunction in the cortex helps to facilitate addictive behavior. We’ll now look at one particular prefrontal segment to understand how this happens.
215
Many studies link addiction to the orbitofrontal cortex (OFC), a cortical segment found near the eye socket, or orbit.5 In drug addicts, whether they are intoxicated or not, it doesn’t function normally. The OFC’s relationship with addiction arises from its special role in human behavior and from its abundant supply of opioid and dopamine receptors. It is powerfully affected by drugs and powerfully reinforces the drug habit. It also plays an essential supporting role in nondrug addictions. Of course, it doesn’t function (or malfunction) on its own but forms part of an extensive and incredibly complex, multifaceted network—nor is it the only cortical area implicated in addiction.
- E. D. London et al., “Orbitofrontal Cortex and Human Drug Abuse: Functional Imaging,” Cerebral Cortex 10(3) (March 2000): 334–42; see also R. Z. Goldstein and N. D. Volkow, “Drug Addiction and Its Underlying Neurobiological Basis: Neuroimaging Evidence for the Involvement of the Frontal Cortex,” American Journal of Psychiatry 159 (2002): 1642–52.
216
Through its rich connections with the limbic (emotional) centers, the OFC is the apex of the emotional brain and serves as its mission control room. In normal circumstances in a mature human being, the OFC is among the highest arbiters of our emotional lives. It receives input from all the sensory areas, which allows it to process environmental data such as vision, touch, taste, smell, and sound. Why is that important? Because it’s the OFC’s job to evaluate the nature and potential value of stimuli—based not only on present information but also in light of previous experience. The neurological traces of early, formative events are embedded in the OFC, which, in turn, is connected with other memory-serving brain structures. So, for example, a smell that in early memory is associated with a pleasurable experience will likely be judged by the OFC in a positive way. Through its access to memory traces, conscious and unconscious, the OFC “decides” the emotional value of stimuli—for example, are we intensely drawn to or repelled by a person or object or activity, or are we neutral? It is constantly surveying the emotional significance of situations, their personal meaning to the individual. Through processes we are not consciously aware of, in microseconds the OFC decides our take on people or on a situation. Since our likes and dislikes, preferences and aversions strongly influence what we focus on, the OFC helps us decide to what or whom we should devote our attention at any given moment.6
- A. N. Schore, “Structure-Function Relationships of the Orbitofrontal Cortex,” chap. 4 in Affect Regulation and the Origin of the Self (Hillsdale, NJ: Lawrence Erlbaum Associates, 1994), 34–61.
216
The OFC—particularly on the right side of the brain—has a unique influence on social and emotional behaviors, including attachment (love) relationships. It is deeply concerned with the assessment of interactions between the self and others and plays a ceaseless (but fundamentally life-essential) game of “Who loves, who loves me not?” It even gauges “How much does he/she love me or dislike me?” While the explicit meanings of words spoken are decoded in specialized portions of the left hemisphere, the right OFC interprets the emotional content of communications—the other person’s body language, eye movements, and tone of voice. One cue the OFC watches for is the size of the other’s pupils: in social interactions, especially in eyes set in a smiling face, dilated pupils mean enjoyment and delight. Babies are highly sensitive to such cues—as are aphasiac adults (people who, usually due to a stroke, have lost the ability to understand spoken language). Because they pay heed to physical and emotional rather than verbal messages, young children and aphasiacs have a much better sense of when they are being lied to than most of us have.
217
The OFC also contributes to decision making and to inhibiting impulses that, if allowed to be acted out, would be harmful—for example, inappropriate anger or violence. Finally, brain researchers have also linked the OFC to our capacity to balance short-term objectives against longer-term consequences in the process of decision making. Imaging studies consistently indicate that the OFC works abnormally in drug abusers, showing malfunctioning patterns in blood flow, energy use, and activation.7 No wonder, then, that psychological testing shows drug addicts to be prone to “maladaptive decisions when faced with short-term versus long-term outcomes, especially under conditions that involve risk and uncertainty.”8 Due to their poorly regulated brain systems, including the OFC, they seem programmed to accept short-term gain—for example, the drug high—at the risk of long-term pain: disease, personal loss, legal troubles, and so on. A regular finding of brain-imaging studies on drug addicts is under-activity of the OFC after detoxification.9 In a similar vein, psychological testing of cocaine addicts has shown impaired decision making. In one study, some key aspects of their decision-making ability was a mere 50 percent of normal. Only people with physical injury to the frontal cortex would score lower.10
-
Goldstein and Volkow, “Drug Addiction and Its Underlying Neurobiological Basis.”
-
London et al., “Orbitofrontal Cortex.”
-
G. Dom et al., “Substance Use Disorders and the Orbitofrontal Cortex: Systematic Review of Behavioral Decision-Making and Neuroimaging Studies,” British Journal of Psychiatry 187 (2005): 209–20.
-
London et al., “Orbitofrontal Cortex.”
218❗️
It may seem paradoxical, but the OFC is also highly activated during craving—not to enhance decision making but to initiate craving itself. It turns out that different parts of the OFC have different functions: one part is involved in decision making, another in the automatic and emotional aspects of craving.11 In imaging studies the OFC lights up when an addict so much as thinks about her drug.12 An abnormally functioning OFC has also been implicated in compulsive behaviors in both human and animal studies. A rat with a damaged OFC will persevere in reward-seeking, addiction-type activities even after the rewards are removed. As the researchers comment, “these findings are reminiscent of the reports of drug addicts who claim that once they start taking a drug of abuse they cannot stop even when the drug is no longer pleasurable.”13
-
Ibid.
-
Goldstein and Volkow, “Drug Addiction and Its Underlying Neurobiological Basis.”
-
N. D. Volkow et al., “Low Level of Brain Dopamine D2 Receptors in Methamphetamine Abusers: Association with Metabolism in the Orbitofrontal Cortex,” American Journal of Psychiatry 158(12) (December 2001): 2015–21.
220
But what about the “choice” I said she had when I was talking with her in my office—the choice to use cocaine the day before in the first place? Let’s consider that question from the perspective of brain activity. It is not hyperbole to say that drugs have been the chief source of consolation that Claire, now in her thirties, has ever found. Ever since she began using in adolescence, they’ve offered her relief from searing emotional pain, loneliness, anxiety, and a deep-seated fear of the world. As a result, her OFC has been trained to create a powerful emotional pull toward the drug from the second she even thinks about “fixing.” Addiction research refers to this dynamic as salience attribution: the assignment of great value to a false need and the depreciation of true ones. It occurs unconsciously and automatically. We can now reconstruct yesterday’s events. When Claire sees the plastic bag with the white cocaine powder, the needle, and the syringe—or when she so much as thinks about them—her brain will respond in a highly positive way. Owing to the OFC’s influence on the incentive centers described in the last chapter, dopamine will start flowing in Claire’s midbrain circuits. This causes the craving for the drug to intensify. Any thoughts of negative consequences are thrust aside: the part of the OFC that might speak up to warn her of these consequences is “gagged and bound.” Thus Claire’s OFC, impaired by years of drug use and perhaps even before then, encourages the self-harming activity rather than inhibiting it. She injects. Ten minutes later she takes her seat outside my office. Someone says the wrong thing—or she believes they do. Her OFC, unconsciously primed to recall the many times she has been attacked, insulted, and injured, interprets this stimulus as a serious aggression. Claire is triggered. According to PET scans, the OFC distinguishes and reacts to angry, disgusted and fearful facial expressions in other people but not to neutral facial expressions.14 Literally, all the “offending” person had to do was to look at Claire the wrong way.
221
In this chapter we have seen that the OFC, a central part of the brain system that regulates how we process our emotions and how we react to them, participates in substance dependence in a number of ways. First, it emotionally overvalues the drug, making it the chief concern of the addict—and often the only concern. It undervalues other objectives, such as food or health or relationships. By becoming triggered even at the thought of the drug (or activity) of choice, it contributes to craving. And finally, it fails at its task of impulse inhibition. It aids and abets the enemy. Attacking energy, expressed as tantrums or aggression, rapidly erupts from a young child because the brain circuits that would allow him to resolve his frustrations in other ways are as yet unformed. The impulse-control circuitry isn’t connected yet, either. Don, who has been a user since his adolescence, was never very mature to begin with. Decades of life as a drug addict have permitted very little continued maturation of either his behavior or his brain. His experience tallies up with studies showing that the volume of drug users’ gray and white matter is diminished and that this loss of cortical mass is correlated with length of drug use.15
- G. Bartzokis et al., “Brain Maturation May Be Arrested in Chronic Cocaine Addicts,” Biological Psychiatry 51(8) (April 2002): 605–11; Goldstein and Volkow, “Drug Addiction and Its Underlying Neurobiological Basis.”