Depression, Obsessions, and Compulsions: Concepts in Ethology and Attachment Theory
If it is neurotransmitters that determine, at least in part, whether or not we will be depressed, then what forces shape the production and transmission of these neurochemicals in the brain? It turns out that the mother-child relationship is critical to our developing brains. And it goes beyond that. Loneliness and social isolation contribute to depression. We may not need everybody but all of us need somebody. Animals, including us humans, seek out companionship. The need for it is programmed into our ancestral brains. The image to the left shows Suryia the orangutan and Roscoe, the Blue Tick Hound. While living at the Institute of Greatly Endangered and Rare Species in Myrtle Beach, South Carolina, Suryia one day came across the path of a down-and-out dog and they have since become best friends and constant companions.
In "A Gene for Nothing," published in Discover, October, 1997, Robert Sapolsky writes: "Periods of psychological stress involving loss of control and predictability during childhood may well predispose one toward adult depression." He points out that the timing of losses is important. Given identical losses and stress, a child who experiences misfortune over a one-year period instead of over a six-year period is more likely to develop depression.
In the middle part of the last century, Harlow F. Harlow studied the effects of isolation on baby monkeys. To do this, he removed any semblance of a mother or other companion, and provided only nutritional sustenance. As Deborah Blum points out in Love at GOON Park, Harry Harlow and the Science of Affection (2002), the monkeys sunk into a despairing stupor similar to symptoms of severe depression in humans. After thirty days, on removal from isolation, the monkeys were so disturbed that, according to Blum's account, "two of them refused to eat and starved themselves to death." Blum interviewed professionals who worked with Harlow, now deceased, on the isolation experiments. After being isolated for six months, a horrific picture emerges, explains Blum including "animals stumbling blindly around their cages, rocking themselves, chewing their skin open."
Harlow is pictured at right (image links to source). Erin Schultheis, Muskingum University, compiled the webpage from which this picture is taken. Regarding depression, Blum quotes Harlow: "In other words, depression results from social separation when the subject loses something of significance, has nothing with which to replace that loss, and is incapable of altering this predicament by its own actions."
The late Saul Schanberg, a renowned nueroscientist and physician at Duke University, is recognized for his research "on the importance of touch in normal growth and development," states the 2009 Duke Medical Alumni News. Schanberg found that "specific types of touch led to better health and shorter hospital stays for premature infants." Schanberg's experiments emphasize the importance of attachment, especially involving contact comfort, in normal mammalian development. Blum writes: "Schanberg found that when mother rats licked their babies, the action produced a cascade of much needed compounds, in fact, the growth hormones that produce normal body development. Remove the mother—remove the touch of her tongue, and the baby rats became stunted beings."
Regarding attachment and subsequent mental health, Martin Teicher and his team at McLean Hospital, a psychiatric teaching affiliate of Harvard Medical School, have "been using brain imaging technologies to compare people from a safe and protective family and those who grew up in an abusive one," writes Blum in Love at GOON park. She quotes Teicher: "We know that any animal exposed to stress and neglect early in life develops a brain that is wired to experience fear, anxiety, and stress. We think the same is true of people." I will provide here a link to a news article about the Teicher team's work titled "Cutting Words May Scar Young Brains."
Monkeys from the Harlow laboratory are pictured at left and below. These images link to their source, Classics in the History of Psychology. Christopher D. Green, York University, Toronto, developed this internet resource.
Harlow describes his early work in "The Nature of Love" (1958), first published in American Psychologist. Harlow and his team separated macaque monkeys from their mothers shortly after birth and suckled them on tiny bottles in a laboratory setting. The monkeys displayed a "strong attachment to the cloth pads (folded gauze diapers) which were used to cover the hardware-cloth floors of their cages," writes Harlow. "The infants clung to these pads and engaged in violent temper tantrums when the pads were removed and replaced for sanitary reasons."
Later, experiments with surrogate mothers in the form of either a bare wire mother or a cloth-covered model further illustrated the infant monkeys' intense need for contact comfort. In "The Nature of Love," Harlow writes: "With age and opportunity to learn, subjects with the lactating wire mother showed decreasing responsiveness to her and increasing responsiveness to the nonlactating cloth mother." When Harlow removed mother surrogates from infant monkeys, the frustrated infants often engaged in abnormal behaviors including rocking, sucking, and frantic clutching of their bodies. This even for a mother made of wire and cloth.
Scientists in Harlow's laboratory studied the mothering skills of a few female monkeys that had been raised in isolation. The scientists used forced pregnancies, since these particular females had no social intelligence and were unreceptive to mating. Blum writes: "These monkey mothers that had never experienced love of any kind were devoid of love for infants, a lack of feeling unfortunately shared by all too many human counterparts. Most of the loveless mothers just ignored their infants. Unfortunately, not all did. One held her infant's face to the floor and chewed off his feet and fingers. Another took her baby's head in her mouth and crushed it. That was the end of the forced pregnancies."
Blum includes a statement Harlow made to This Week, March 3, 1961: "If monkeys have taught us anything it's that you've got to learn how to love before you learn how to live."
We will further discuss the parent-child relationship and what is called attachment theory, below. But first, we will take a look at hospitalism, which Wikipedia defines as a "pediatric diagnosis used in the 1930s to describe infants who wasted away while in hospital." In essence, during this era of medicine, well-meaning physicians isolated human infants with tragic results.
John B. Watson, a godfather of American behaviorist psychology, is pictured at left testing the grasp reflex of a baby, circa 1916-20. The New York Times published this photograph, originally from the Johns Hopkins University archives.
In the first half of the twentieth century, prominent psychologists came to view competent mothering as simply the provision of shelter and sustenance combined with appropriate stimuli to condition desired behavior. Such resources and stimuli could be measured, thus convincing psychologists that their science was real. "Give me a dozen healthy infants … and my own specified world to bring them up in," said behaviorist John B. Watson, "and I'll guarantee to take any one at random and train him to become any type of specialist I might select … regardless of his talents, penchants, tendencies, abilities, vocations, and the race of his ancestors."
"Behaviorists believed that behavior could be understood independently of the rest of biology, without attention to the genetic makeup of the animal or the evolutionary history of the species," asserts Steven Pinker in The Blank Slate: The Modern Denial of Human Nature (2002). Pinker writes: "As late as 1974, Skinner wrote that studying the brain was just another misguided quest to find the causes of behavior inside the organism rather than out in the world."
During the reign of the behaviorists, mothers who fussed over their babies were labeled neurotic. Variables in children's individual temperaments were not considered consequential. It wasn't the special quality of a mother's touch in changing a diaper that was deemed important. It was the diaper change that made the difference. Any competent caregiver would do. Meanwhile, germ theory increasingly defined the practice of medicine. In hospitals, sick infants and young children were placed in very sterile, isolated environments. Parents were not allowed daily visits. Doctors discouraged handling of the small patients in order to deter germ transmission. Regardless of the sterile conditions, however, many of the children succumbed to a disease state eventually referred to as "hospitalism" and died.
In Monkeyluv and Other Essays on Our Lives as Animals, (2005), Robert M. Sapolsky sums up the situation.
The infants in hospitals, despite adequate nutrition, a sufficient number of blankets, and various medical menaces kept at bay, wasted away from emotional deprivation. And as they became depressed and listless, their immune systems were likely to weaken (as has been shown for young nonhuman primates undergoing similar deprivation). Soon they'd be falling victim to the gastrointestinal or respiratory infections so common in hospitals at the time, at which point, the feverish medical enthusiasm for aseptic isolation would kick in. The pediatricians would see the infections as a cause, rather than an effect of hospitalism, and the kids would quickly be consigned to isolated cubicles where the goal would be their never being touched by human hands. And the mortality rate would soar.
In The Tangled Wing: Biological Restraints on the Human Spirit (2002), Melvin Konner explains that the study of ethology assumes that "many aspects of the behavior of a species are as fixed as its anatomy and are equally attributable to genes." This should not be interpreted to mean, however, that our genes are our destiny. The cues an animal gets from the environment also drive behavior. Ethologists travel far and wide to observe gene-environment interactions.
In "Family Man" (Discover, October 1997) Will Hively writes about Stephen Emlen's study of the white-fronted bee-eater birds of Kenya. (A white-fronted Bee-Eater is pictured above left and links to source, courtesy of Birdfinders Tours.) Emlen explains that whether or not a bee-eater bird helps another bird care for young is "very much predicted on closeness of kinship." Although the bee-eaters appear altruistic at first, Emlen points out more important forces behind their behavior. "We're not talking about the evolution of a gene for altruism. It isn't the behavior per se the gene is regulating." Emlen prefers to think of genes as decision rules. When functioning optimally, genes provide animals with the ability to evaluate environmental context and choose a behavior most likely to result in replicating genes. As Hively points out in the article, in the animal kingdom, genes provide animals with the ability to recognize kin, often using smell to do so. And as Emlen has discovered, bee-eaters are most helpful to their close kin. Their behavior, which Emlen characterizes in such terms as helping, infanticide, sexual conflict, or dispersal, is most often based on their genetic relationship to the birds around them.
As in Emlen's work described above, traditionally, the science of ethology has focused on the study of animal behavior in a natural, wild habitat. Ethologists have paid special attention to instinctual behaviors. In The Boy Who Couldn't Stop Washing: The Experience & Treatment of Obsessive-Compulsive Disorder (1989), Judith L. Rapoport succinctly writes, "Ethology, founded by Charles Whitman and Oskar Heinroth in the late nineteenth century, and brought to recognition by
Konrad Lorenz in the 1930s, is the study and comparison of animal behaviors."
In The Foundations of Ethology, originally published in 1978, Konrad Z. Lorenz (R.W. Kickert, translator) describes the emergence of ethology: "At the turn of the century Charles Otis Whitman and, a few years later, independently of him, Oskar Heinroth discovered the existence of patterns of movement, the similarities and differences of which, from species to species, from genus to genus, even from one large taxonomic group to another are retained with just as much constancy and in exactly the same way as comparable physical characters. In other words, these patterns of movement are just as reliably characteristic of a particular group as are tooth and feather formation and such other proven distinguishing physical attributes used in comparative morphology."
Lorenz took the study of movement and expanded it to the study of behavior. He is famous for his work with goslings. In Love at GOON Park, Deborah Blum has this to say about Lorenz: "Lorenz was able to show that this first loyalty was given to the 'mother' first seen by the tiny birds. The 'mother' thus could be Lorenz, actually, if he was hovering over the nest when Greylag goslings … first cracked their way out of the egg shells. … If you considered Lorenz's studies seriously, though, you realized they were a reminder that nature fully intends a helpless baby to be well connected to a protector. In the geese, the attachment might seem hard-wired." In the photograph above left, you can see that a brood of young goslings have imprinted Lorenz as their mother (photo links to its source—an entry for Lorenz in a Russian Federation academic encyclopedia).
Blum's observations are in line with discoveries in neuroscience we discuss in Part 2 of MyBrainNotes.com relating to CARE system neurocircuitry, which governs nurturance behaviors, and PANIC/LOSS neurocircuitry, which prompts young animals to emit a separation cry to signal their whereabouts to their mother.
"Becoming Attached" (The Atlantic, Feb. 1990), Robert Karen discusses how Konrad Lorenz's work influenced John Bowlby, a British psychoanalyst, who originated attachment theory. "Lorenz's work on imprinting in newborn goslings, a phenomenon by which the infant birds attach themselves to the first moving object they see," particularly influenced Bowlby, notes Karen. "Captivated by ethological ideas, Bowlby now had a biological basis for his belief that a child needs a reliable ongoing attachment to a primary caregiver and that he suffers grievously, even irreparably, if that attachment is interrupted or lost. He developed the concept of 'internal working models' to describe how the infant's sense of self and other unfolds through interactions with that primary caregiver."
Karen explains that subsequently, "Mary Salter Ainsworth's Strange Situation put attachment theory on the map, by providing empirical evidence for a number of conclusions that until then had only been intuited." What Ainsworth demonstrated was that human infants develop particular attachment styles. Securely attached children are usually outgoing, optimistic, and confident they will receive support from parents or other caretakers. Insecurely attached children are timid, do not embrace new situations, and are either clingy or avoidant. In Affective Neuroscience: The Foundations of Human and Animal Emotions (1998), Jaak Panksepp has this to say about insecurely attached
children: "Perhaps they have felt rebuffed so often that they no longer reach out to others. In order to subsist comfortably, they have become cognitively detached from their emotional desires."
If attachment is hard wired in animals including humans, then one must ask what happens if circumstances disrupt attachment? The result, I think, can often be described as frustration. And although there are a wide range of etiologies for the onset of depression and obsessive-compulsive symptoms, I contend that frustration or chronic stress related to attachment issues can sometimes cause depression and initiate or otherwise kindle existing or latent OCD symptoms. Frustration can, I think, activate and potentiate atavistic fixed-action patterns encoded in the animal brain, turning such patterns into dangerous stereotypies. We will discuss fixed-action patterns and stereotypies below.
So what starts out as OCD can, I think, turn into a more dangerous, dissociative disorder, especially when you take one of Panksepp's suppositions into account—that the neurocircuitry in an insecurely attached child's brain can be conditioned over time to detach certain emotional attachment needs originating in the mammalian brain from higher, cortical-based cognitive processes. In Part 3 of MyBrainNotes.com we will discuss a concept termed parallel processing that might explain such detachment in more severe cases of OCD.
Martin Teicher and his team conducted the study that produced the image above left (image links to source). In this image, diffusion tensor imaging reveals a tractography analysis of the cingulum bundle fiber pathways. The small yellow area indicates a disruption in the pathways in a subject who experienced parental verbal abuse. I have flipped this image horizontally to match the orientation of the photograph above right delineating the position of the anterior cingulate cortex which we discuss in Part 1 of MyBrainNotes.com (see The anterior cingulate cortex–emotion, attention, and working memory). John A. Beal, Department of Cellular Biology and Anatomy, Louisiana State University, provides this photo (links to source).
I would like to again point out an observation that Antonio R. Damasio makes in Descartes' Error: Emotion, Reason, and the Human Brain (1994). He writes: "I would like to propose that there is a particular region in the human brain where the systems concerned with emotion/feeling, attention, and working memory interact so intimately that they constitute the source for the energy of both external action (movement) and internal action (thought animation, reasoning). This fountainhead region is the anterior cingulate cortex… ."
Teicher made a very interesting observation related to what I call detachment. In the article Cutting Words May Scar Young Brains, regarding the differences seen in brain images of people who have a past history of verbal abuse from parents, Teicher says: "The brain is probably suppressing the development of sensory systems that are providing adverse input." In doing so, I contend that such individuals learn how to detach intellectual processing from more emotive processing. In doing so, they inadvertently empower the subcortical animal brain's emotional systems to sort of hijack behavior, sometimes resulting is obsessive-compulsive symptoms.
According to her webpage, researcher Mechthild Papoušek has employed behavioral observation, video and audio recordings of parent-infant interactions, and microanalysis to the minute reciprocities of preverbal communication to study attachment issues. In "The Violent Brain," which appeared in Scientific American Mind (Dec. 2006), Strueber, Lueck, and Roth point to Papoušek's work to underscore the importance of attachment. They write:
As Mechthild Papoušek, [formerly] a pediatric psychiatrist at the Max Planck Institute of Psychiatry in Munich, has shown, intimate communication between the infant and the primary caregiver begins shortly after birth. The two reinforce each other's behavior, both in the positive and in the negative sense. The infant's qualities determine the interaction just as much as the caregiver's personality and psychological state do. And a problematic early relationship can in time lead to severe developmental disorders, among them lowered impulse control, a lack of empathy and a reduced capacity for resolving conflicts. The result is a vicious cycle.
Wikipedia provides a succinct definition of a fixed-action pattern, explaining that it "is an instinctive behavioral sequence that is indivisible and runs to completion."
A network of neurons that fire in response to a very specific stimulus produce fixed-action patterns. The neural network is known as the innate releasing mechanism. The network responds when an animal perceives a sign stimulus or releaser in its environment. I will try and put this into neurological terms: In response to a specific stimulus, a specific network of neurons fire in a certain pattern to produce a certain behavior called a fixed-action pattern. To induce movement, such a neural network projects over several target stations and probably involves a variety of neurochemicals. But when movement is involved, the transmission of dopamine through the corpus striata complex (basal ganglia) is most certainly involved [see The corpus striata (basal ganglia) complex].
Judith L. Rapoport points out in The Boy who Couldn't Stop Washing how hormones can serve as a stimulus for fixed-action patterns. She writes: "Nesting can be started by hormonal change in a pregnant mouse (progesterone is released during pregnancy), and nesting can be started in a non-pregnant mouse by the injection of progesterone."
Temple Grandin and Catherine Johnson provide the following excellent example of fixed-action patterns in Animals in Translation: Using the Mysteries of Autism to Decode Animal Behavior (2005). "A normal rooster does a little courtship dance before trying to mate with a hen. The dance is hardwired into the rooster's brain; it is instinctual behavior, or what animal ethologists call a fixed action pattern. All normal roosters do it." The authors go on to say: "The dance triggers a fixed action pattern in the hen's brain, and she crouches down into a sexually receptive position so the rooster can mount her. She doesn't crouch down unless she sees the dance. That's the way her brain is wired."
In The Trouble With Testosterone and Other Essays on the Biology of the Human Predicament (1997), Robert M. Sapolsky writes: "We all know one familiar example of a fixed action pattern, the involuntary circling of a dog on its blanket before being able to settle down for the night. For a human, OCD is like a dog circling, but a dog, exhausted and bewildered, who can never, ever stop." Later, Sapolsky adds: "The brains of OCD sufferers show enhanced oxygen and glucose utilization in pathways related to motoric patterns—seemingly, there is a neurological itch, a metabolic drive in those brain regions toward fueling the arranging and washing and repetitive gesturing." I should note here, for those of you unfamiliar with canines, that the dog circles around to clear the bedding area—which for its forebearers was tall grass or undergrowth—to make sure not to bed down on another critter, especially a snake.
In The Boy Who Couldn't Stop Washing, Rapoport notes that the "squirrel's ritual of food storage is also what an ethologist would call a 'fixed action pattern.' Squirrels with extra food, even those in cages, will look for places to 'hide' those extra nuts, and go through covering and tamping down movements." Rapoport reports the following experience with a patient caught-up in a fixed-action pattern.
I filmed David, age twelve, plucking lint off his underwear. Meticulously, slowly, he studied each section of the cloth and assembled a midget pyramid of white thread. David always sets about his plucking in the same way. And he always does a perfect job of it, his fingers moving in fine pincer movements. David's undershirt, like several of its predecessors, is about to fall apart. He has, in a sense, picked it "clean."
Rapoport asserts that the source of such compulsive behavior has "to be located somewhere in the brain." She points out that ethologists see this type of behavior often in the animal world. Rapoport writes: "In ethology and its offspring, neuro-ethology, I find a model, a beginning for understanding the fixed patterns I see in our washers (read groomers), ritualizers (read ritual displays), and collectors (read as nesters and hoarders). Neuro-ethologists study the role of the brain in developing these behaviors and in keeping them intact."
Under David's bed is his entire lint collection, the result of three years of thread-pulling. …
David's "squirreling" habits, and the habits of most of our compulsive patients, remind me of many aspects of animal behavior. Their perfectly executed, meticulously deliberate collections look like the nest-building of birds, the hoarding of squirrels.
Some people who suffer from obsessive-compulsive symptoms focus on organizing their environment, symmetry, compiling information, or as Rapoport points out, collecting. Sometimes these tendencies can be helpful, especially if one chooses a compatible profession. I find some similarity between these kinds of focused human behaviors and the behaviors of seed-eating birds since they function in a meticulously organized fashion in order to survive. Panksepp writes: "Seed-eating birds often cache supplies of food far and wide and use remarkable spatial memories in retrieving their hidden tidbits. Indeed, birds that actively hide seeds for later use have larger hippocampi, the brain areas that specialize in processing spatial information, than those that do not."
A stereotypy is a fixed-action pattern out of control. Stereotypies are unvarying, repetitive, patterned behaviors that have become unmoored from their original sign stimulus. They are out of context and irrelevant to the situation in which they occur. They usually occur when an animal is frustrated or restrained in some way. The animal, unable to SEEK what it needs, displaces frustration with some other behavior pattern that can be carried through to completion. For example, when a sheet of glass prevents a thirsty dove from getting to its water bowl, the dove will peck at the ground nearby or preen itself. So what starts out as simple displacement activity becomes a stereotypy under continuing stressful conditions. I should note that in creating this description, I referenced Aubrey Manning's and Marian Stamp Dawkins's An Introduction to Animal Behaviour (1992).
The form stereotypies take depends of the animal's species. In Animals in Translation, Temple Grandin and Catherine Johnson write:
Highly social animals such as dogs and horses need the companionship of other animals or people. Grazing animals such as horses and cattle need hay or grass. Burrowing animals such as rodents need materials to burrow and hide in. Animals that walk long distances such as polar bears and tigers need room to roam. The nervous system of young animals reared in barren kennels or laboratory cages may be damaged because the growing nervous system needs varied sensory input to develop normally. Some of the most abnormal behaviors that occur in barren environments are performed when the animal is undisturbed by people. When people enter the animals stop doing the abnormal behavior.
So how do various frustrated animals displace their motivation to SEEK necessary resources and stimulation? Parrots that lack social companionship will pull out their feathers. Horses will engage in cribbing (repetitively biting on a fence). Sows in gestation cages, where there is no straw for chewing and no dirt for rooting, will bite the cage bars until their gums bleed. John J. McGlone, in Current Status of Housing and Penning Systems for Sows, (2002), provides the image at left (links to source). Dogs compulsively lick a paw, a condition known as acral lick dermatitis. As Grandin and Johnson discuss above, the abnormal behavior most often occurs when frustrated animals are left alone with little stimulation. In primates, stereotypies often play out in self-directed behaviors, such as grooming. Chimpanzees caged in laboratories sometimes compulsively pluck their own body hair. In Love at GOON Park, Deborah Blum recounts how some of the first members of People for the Ethical Treatment of Animals (PETA) exposed laboratories where macaque monkeys were housed in isolation. The monkeys "paced, rocked, clasped themselves, and—introducing injury anyway—chewed on themselves."
What we often fail to realize is that the same animal brain circuitry that generates stereotyped behavior in animals under stressful conditions can also generate stereotyped behavior in humans under stressful conditions. Human stressors exacerbate ADHD, OCD, PTSD, Tourette syndrome, and compulsive grooming symptoms. In Why Zebras Don't Get Ulcers: The Acclaimed Guide to Stress, Stress-Related Diseases, and Coping (2004), Robert M. Sapolsky writes: "When it comes to what makes for psychological stress, a lack of predictability and control are at the top of the list of things you want to avoid."
In humans, perseveration can sometimes be confused with compulsivity. It is important to differentiate between the two because different neurotransmitters are involved and that means different medicines might be employed to treat symptoms. In his video course,
Biology and Human Behavior: The Neurological Origins of Individuality, Robert M. Sapolsky discusses how humans who suffer from early dementia, when they cannot complete a cognitive task, will sometimes fall back on more easily enacted behaviors. He notes that patients with frontal cortex damage or deterioration will resort to something called perseveration and intrusion. He points out that the frontal cortex helps you focus on what the task is right now. So when you ask early state dementia patients to count backward from 20, they will sometimes start the task but then revert to reciting something over learned and more firmly established in memory, such as the months of the year. Instead of doing the cognitively harder thing via the frontal cortex, the patient reverts to a previous, easier task. In finding and using substitute language and facts, these patients are resorting to perseveration, accessing information that has been learned through life experience. Regarding fixed-action patterns and stereotypies, it is pattern generators genetically inculcated in subcortical structures over generations that dictate behavior. Out-of-control dopamine activation of these pattern generators is more likely the cause of compulsions. This is not to say, however, that there are not situations where compulsion and perseveration combine to create what would be extremely problematic symptoms.
Regarding fixed-action patterns and stereotypies, it is our subcortical nuclei—that part of our human brains so similar to the brains of other mammals—that are most prominently in control. The transmission of dopamine to subcortical areas that in turn connect to areas of our neocortex, sending movement messages to this or that muscle, is the mechanism responsible for this automatic-like behavior. According to Jaak Panksepp in Affective Neuroscience, in animal experiments where the cortex is removed from an animal's brain, the decorticate animal is hyperactive, prone to "jump rapidly from one activity to another." Panksepp observes that without cortical processing to shape subcortical motivation, these animals display symptoms similar to those impulsive symptoms seen in children suffering extreme attention deficit hyperactivity disorder (ADHD). The neurotransmitter most at work in shaping dopamine-driven subcortical motivation once it reaches the cortex is norepinephrine (see Norepinephrine action, synthesis, and pathways). So when either dopamine or norepinephrine levels are out of whack, some kind of symptoms will occur.
Note: If you are interested in ADHD symptoms and have not yet read
Attention, Learning, and Memory: The VIGILANCE System in Part 2 of MyBrainNotes.com, then I urge you to do so.
According to the Merck Manuals Online Medical Library, there are three types of ADHD. The first is characterized as predominantly inattentive. The second is characterized as predominantly hyperactive-impulsive. And a third type is characterized as being a combination of inattentiveness and hyperactivity-impulsiveness. It is important to consider whether these different symptom pictures represent distinctly different imbalances in brain neurotransmitters.
As we discuss above, perseveration can occur in ADHD as well as in dementia. In addition to symptoms of speech and cognition, perseveration can also present as more of a physical-type behavior or movement. Perseveration can be defined as repetitive movement or repetitive speech that focuses on one idea or task, thereby overlooking more significant stimuli that would normally prompt a behavior change. Perseverative behavior often has a compulsive quality to it so you can see how perseveration might be mistaken for compulsion and thus labeled as inappropriate. As we discuss in Norepinephrine action, synthesis, and pathways, it is norepinephrine—transmitted in long, branching axons from loci coerulei in the pons of the brain stem to the left and right cortical areas—that enables the cortex to register the consequence of incoming stimuli and determine which stimulus is most worthy of immediate attention. So inadequate norepinephrine contributes to perseveration while excessive dopamine contributes to compulsions. And again, it is probably not always an either-or situation. Sometimes, imbalances may exist in both norepinephrine and dopamine pathways.
In Affective Neuroscience, Panksepp explains that "with excessive DA [dopamine] activity, animals begin to exhibit repetitive behavior patterns known as stereotypies; with low NE [norepinephrine] activity, they tend to perseverate on a task despite changes in stimulus contingencies (presumably because of attentional deficits)." Panksepp cites research to conclude: "Existing evidence suggests that NE promotes sensory arousal, while DA promotes motor arousal. As we would expect from such functional considerations, NE terminals are concentrated in sensory projection areas of the cortex, while DA terminals are more prominent in motor areas."
In regard to human illnesses such as OCD and ADHD, then, I think it may therefore be appropriate to say that excessive dopamine often drives compulsions whereas inadequate norepinephrine and/or inadequate dopamine often drives perseveration.
Researchers have suggested that high levels of dopamine transporters are associated with ADHD. During some of my research on dopamine, I found a 2006 report titled "High Dopamine Transporter Levels Not Correlated with ADHD." The U.S. Department of Energy's Brookhaven National Laboratory, in collaboration with Mount Sinai School of Medicine in New York, produced the report. Researchers used positron emission tomography (PET) technology to study dopamine transporters in the brain. PET scan images such as the ones below (link to source) show that patients in the study with ADHD had lower levels of dopamine transporters in the nucleus accumbens when compared to control subjects. (We will discuss the nucleus accumbens in greater detail later in this narrative.)
The authors of the study, including Nora Volkow, Director of the National Institute on Drug Abuse, and Gene-Jack Wang, from Brookhaven, speculate that rather than having high levels of dopamine transporters in the brain, as others have suggested, ADHD patients suffer inattentive symptoms due to lower levels of dopamine release. Volkow reports: "These findings suggest that an additional variable in conjunction with dopamine transporters would be required to account for the severity of the symptoms of inattention in ADHD." Volkow goes on to say: "We speculate that this other variable may be lower levels of dopamine release in ADHD subjects." If the Brookhaven study findings are correct, then these circumstances help explain why psychostimulants, which make dopamine more available, help improve attention in some patients.
During our discussion of the VIGILANCE system in Part 2 of MyBrainNotes.com, in a subsection titled Stress, attention, learning, memory, and ADHD, we discuss Amy F.T. Arnsten's work. In Norepinephrine Has a Critical Modulatory Influence on Prefrontal Cortical Function," (2000), she reports that "NE [norepinephrine] cells of the locus ceruleus [also spelled locus coeruleus] increase their firing in response to behaviorally relevant stimuli. Selective depletion of NE in the forebrain makes animals more distractible." Arnsten cites dysfunction in the prefrontal cortex as a fundamental component of ADHD. Arnsten explains that the prefrontal cortex "uses working memory to intelligently guide behavior, inhibiting inappropriate impulses or distractions and allowing us to plan and organize effectively." Arnsten notes that it is both norepinephrine and dopamine that accomplishes attentiveness in the prefrontal cortex.
Arnsten explains that the nonselective norepinephrine reuptake blocker, the tricyclic antidepressant desipramine, and the newer, selective norepinephrine reuptake blocker, atomoxetine (a non-stimulant), have been shown to ameliorate ADHD symptoms. Atomoxetine also increases dopamine availability in the brain.
It is not my intent to recommend any specific drug. I am not a medical professional and I do not know anything about ADHD except what I have included here in MyBrainNotes.com. But I do know, from personal experience with OCD, that discovering as much as you can about specific symptoms, and the neurotransmitters involved in particular behaviors, can help patients, parents, and doctors make more informed decisions about medications. I would like to stress, however, that if dopamine-driven obsessions or compulsions are present, rather than perseveration, then a dopamine agonist—which increases dopamine availability in the brain—might exacerbate OCD symptoms. I provide this caution because later in this narrative, I include discussion of low-dose dopamine antagonists in the treatment of obsessions and compulsions; a dopamine antagonist reduces dopamine availability in the brain. That is why it is so important, I think, to differentiate between compulsivity and perseveration.
In researching ADHD medications and their actions, a definition from MedlinePlus Dictionary might be helpful. The term "adrenergic" means "liberating or activated by adrenaline or a substance like adrenaline." Adrenaline and epinephrine are the same biochemical. We discuss epinephrine and ANS—the autonomic nervous system, including the fight-or-flight response, in Part 1 of MyBrainNotes.com. Stimulants sometimes used to treat ADHD are considered to be adrenergic. Also, remember that we discuss Norepinephrine action, synthesis, and pathways in Part 2 of MyBrainNotes.com.
Below are a few resources that might be helpful if you are researching medications for ADHD. When I initially found these resources, I was able to provide a direct link for all items. Access to NeuroPsychiatry Reviews has since been removed, for reasons unknown. A librarian, especially if associated with a medical school library, may be able to help you access hard-to-find materials.
Donald E. Greydanus provides a short overview of ADHD drugs
in "Psychopharmacology for ADHD in Adolescents: Quo Vadis?" (2003). Although I am unable to supply a direct link to this article, you may enter the title into Google search to access it. A short advertisement precedes the article.
Peter Doskoch, in NeuroPsychiatry Reviews, addresses use of tricyclic antidepressants such as desipramine and imipramine in "ADHD: What to do When Stimulant Treatment Fails" (2002).
Jessica Dziedzic, in "Defending the Phenotype—Identifying True ADHD" (2008), in NeuroPsychiatry Reviews, provides information that may be helpful in clarifying some ADHD issues.
The link provided here will require you to register (free) with Medscape Today to view "Atomoxetine: The First Nonstimulant for the Management of Attention-Deficit/Hyperactivity Disorder" (2004). Regarding pharmacology, Corman, Fedutes, and Culley state: "Animal models have demonstrated that atomoxetine increases by threefold extracellular norepinephrine and dopamine concentrations in the prefrontal cortex, an area responsible for attention, judgment, self-monitoring, memory, motor sequences, and impulse control, but does not alter serotonin levels."
Regarding the stimulant, dextroamphetamine, Wikipedia notes that the drug can trigger "a cascading release of catecholamines." At the bottom of the Wikipedia entry are included a variety of hyperlinked references. Both norepinephrine and dopamine are catecholamines (also see Monoamines and catecholamines—notes on molecular structures in Part 2 of MyBrainNotes.com).
In discussing fixed-action patterns, it is easy to correlate the actions of a squirrel hiding nuts with the compulsions of those who hoard possessions. It may not, however, be as simple as activation of a dopamine-driven fixed-action pattern. As we discuss above, inadequate norepinephrine can play a significant role in perseveration, which is sometimes difficult to distinguish from compulsivity. In an editorial titled
"Is Compulsive Hoarding a Genetically and Neurobiologically Discrete Syndrome? Implications for Diagnostic Classification," Sanjaya Saxena looks at a variety of studies about compulsive hoarding and defines it as follows: "Compulsive hoarding and saving leads to clutter that can cover living and work spaces, rendering them unusable. Hoarding frequently causes significant impairment in social and occupational functioning. In severe cases, it can produce health risks from infestations, falls, fires, and inability to cook or eat in the home." It is interesting that Saxena cites four studies that have specifically recruited compulsive hoarders and "found that many of them do not have other OCD symptoms (emphasis added)."
When you look behind the result of hoarding—an unmanageable volume of possessions—a symptom picture emerges. Saxena cites several reports indicating that hoarders have significant difficulty making decisions, including "Compulsive Hoarding: Current Status of the Research," in which Steketee and Frost point out that hoarders have "information processing deficits" in attention, organization, memory, and decision-making. In "A Cognitive-Behavioral Model of Compulsive Hoarding," Frost and Hartl have conducted research that indicates compulsive hoarders "are slow in completing tasks; frequently late for appointments; and display circumstantial, overinclusive language." Another way to put it is that hoarders often go on and on and on. This sounds a lot like perseveration. Previously, I wrote that perseveration is best defined as repetitive movement or repetitive speech that focuses on one idea or task, thereby overlooking more significant stimuli that would normally prompt a behavior change. I am not saying that dopamine-driven fixed-action patterns do not play any role in hoarding. But I think it is important to consider whether inadequate norepinephrine in the frontal cortex, the imbalance most associated with ADHD, plays a role in producing hoarding symptoms.
UPDATE 9/2010: Lew Mills, Ph.D., who specializes in psychotherapy for adults with ADHD,
discusses ADHD and hoarding in "Hoarding and Clutter," an internet resource.
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