ANXIETY DISORDER
SITUATION/DANGER
Phobia of small animals
Possible damage by the animal
Fear of heights
Injury from falling
Panic attacks
Attack by a predator or human
Agoraphobia
Attack by a predator or human
Social anxiety
Loss of social standing
Hypochondriasis
Sickness
Fear of being unattractive
Social rejection
Fear of needles and fainting
Injury/bleeding
A few fears are built-in automatic responses,17 but most common fears are not exactly innate. Fear of snakes, for instance, is not built in, but the brain is prewired to learn it fast, as shown by lovely experiments conducted by psychologist Susan Mineka and her colleagues in the 1970s. Young laboratory-raised monkeys reach blithely across a toy snake to get a treat. However, watching a single video of another monkey withdrawing in fright from the same toy snake created an enduring fear. Watching another monkey apparently withdrawing in fear from a flower created no similar fear.18 The brain is prepared to learn to fear to some cues much faster than to others.
This is social learning of the most useful sort. Instead of a system that responds to only a few rigid cues, natural selection shaped a system that uses information from other individuals. Such fears can be transmitted from generation to generation. For instance, blackbirds were trained to fear a harmless honeyeater bird by showing them a doctored video. They transmitted that useless fear to six other birds in sequence.19 Parents who fear spiders, snakes, or public restrooms can similarly transmit their fears to their children.
We can learn to fear novel dangerous objects, such as electrical sockets, drugs, and knives, but such learning is slow because those cues have no prewired connection to fear. The dangers of driving offer a telling and tragic example. Driving a car is the riskiest thing young people do. It is the single largest cause of death and devastating permanent injury. Nearly a quarter of all deaths in 2014 of people aged fifteen to twenty-four were due to motor vehicle accidents.20 Worldwide, that is about three thousand per day.21 Driver’s education classes emphasize the risks of driving fast and of drinking while driving, but they don’t generate nearly enough caution to provide reliable protection.
Panic Disorder
Panic attacks often come out of the blue. The first one may strike while reading a book, watching television, or waiting for a plane to take off. With no warning, the heart starts pounding, muscles tense, and the victim feels short of breath, a sense of impending doom, chest tightness, and a desperate urge to get away. Most people think they are having a heart attack or stroke, so they go to an emergency room, where they are given all kinds of tests. Far too many healthy young people get coronary arteriograms because their physicians missed the diagnosis of panic disorder.
Many of our patients reported being told in the ER, “We can’t find any specific heart problem, but you should be very careful and come back immediately if things get worse.” Such advice is the perfect way to transform an ordinary anxiety attack into a debilitating panic disorder. The patient begins monitoring for hints that the same kind of episode might be starting again. Soon enough, whether because of mowing the lawn or having an argument, the heart rate increases and the person feels short of breath. These symptoms arouse fear that an attack is beginning, causing a higher heart rate and more shortness of breath that spirals mild anxiety into a full-blown panic attack.
Some research attributes panic attacks to flaws in stress regulation mechanisms. A quick spurt of corticotropin-releasing hormone (CRH) from a brain center called the hypothalamus causes physiological arousal that nearly matches the experience of panic.22 CRH excites cells in the locus coeruleus, so named because it is a blue-colored spot in a lower part of the brain. It contains 80 percent of the neurons that contain noradrenaline.23 Electrical stimulation of the locus coeruleus causes symptoms like those of a typical panic attack. Some researchers suspect that panic attacks are caused by an abnormality in CRH or the locus coeruleus. Some may be, but usually the locus coeruleus is activated by signals from far higher in the brain.
The capacity for having a panic attack is nearly universal. Questionnaire studies find that most adults can recall experiencing paniclike episodes. Panic attacks induce a consistent constellation of symptoms including sweating, rapid pulse, shortness of breath, muscle tension, tunnel vision, acute hearing, fear of fainting, and a desperate urge to flee. As noted already, Walter Cannon recognized the utility of these responses in the face of danger. For our ancestors, that would most often have been in the presence of a predator or hostile human. This all seems abstract, but imagine kneeling by a pool to get water for your family and spotting a crouching lion on the far bank. Our ancestors were not all the same. Some experienced awe at the lion’s strength or no response at all. They became lion lunch. Others dropped everything and fled to the nearest tree. They survived to live another day, and their genes survive in us.
I did a house call for a woman who had not left her trailer for years. Even putting one foot on the stairs to the outside caused terror. It took a few months, medications, and help from relatives, but she was finally able to get out and about again. People with her disorder, agoraphobia, experience intense fear when they leave their homes. They also fear wide-open spaces and enclosed places. That is an odd combination. If you are afraid of wide-open spaces, why also be afraid of enclosed places?
Most agoraphobia is a complication of panic attacks, and agoraphobics often experience panic symptoms when they leave the house. When they do go out, they stay close to home and close to trusted friends. All kinds of explanations have been proposed for the association of agoraphobia with panic disorder. Neuroscientists have looked at brain regions that might influence both. Freud was convinced that fear of being out on the street was a result of unconscious sexual impulses to become a streetwalker. That wasn’t as daft as it now seems. Most of his patients did have wishes for more and better sex, and women alone on the street do encounter sexual opportunities. But there is an easier explanation for the association of agoraphobia with panic attacks.
Imagine you are a hunter-gatherer who narrowly escaped a lion yesterday. What would be smart to do today? Stay in camp if you can. If you must go out, don’t go far and don’t go alone. Avoid wide-open spaces and enclosed spaces, where you would be especially vulnerable to a predator. If any sign of danger arises, flee to home and safety as fast as you can. As the behavioral ecologists Steven Lima and Lawrence Dill put it, “Few failures . . . are as unforgiving as failure to avoid a predator; being killed greatly decreases future fitness.”24
Most patients with panic disorder have never encountered a lion or anything else especially dangerous. Their attacks are false alarms in an otherwise useful system. These false alarms motivate more monitoring, causing increased arousal and increased system sensitivity in a vicious cycle that makes further attacks more likely.
For years, I explained to panic patients that they did not have heart disease or epilepsy, they were experiencing panic attacks, and they needed psychiatric treatment, not more medical evaluation. After listening politely, many said something like, “But, Doctor, it is not mental, it is physical. When an attack comes, I can feel my heart pounding, and I get short of breath. Do you know of a good cardiologist?”
My emerging evolutionary understanding changed my approach.25 I began telling patients that the symptoms of panic are useful for escaping life-threatenin
g danger and that panic attacks are false alarms, like the shrieking of a smoke detector when the toast burns. On hearing this, about a quarter of my patients said something like, “Thanks, Doctor, that makes sense. That’s all I need to know. If I need more help, I will give you a call.”
The rest needed further treatment. Behavior therapy works well for most cases of panic disorder, but medications are also effective. Antidepressants, taken consistently for a few weeks, stop panic attacks for most patients. However, many continue to have “miniattacks” in which they feel a panic attack coming on, but, like a stifled sneeze, it never quite goes all the way. Some patients worry that the medication is “just covering up my symptoms so they will come back when I stop the pills.” They appreciate learning why this is uncommon; the body adjusts the sensitivity of the anxiety system depending on how dangerous the environment is. Several months without panic attacks make the system less sensitive, so future attacks are less likely, even after medication is stopped.
Posttraumatic Stress Disorder
People who come close to death are often changed in ways that make ordinary life impossible. Most people who live in safe neighborhoods and who have never experienced combat cannot even imagine the terror of watching a friend being blown to pieces. The stories of some patients are traumatic even to hear. A man crawled out of a burning car as it exploded with his friends inside. A woman was kidnapped, raped, stabbed, and left for dead. A woman working alone in a laundry had her arm trapped between the hot metal blades of the pants press for fifteen horrifying minutes.
Such close encounters with death change people forever. Many constantly relive the traumatic experience in nightmares and flashbacks. Some feel overwhelmed by fear every minute of their lives. Tiny cues—a distant helicopter, a slammed door, a stranger approaching—arouse fear as intense as the actual danger. To try to avoid such cues and the terror they provoke, some people live in a basement, move to a rural area, or avoid going out. Others feel numb, as if all emotions are dead, except for sudden outbreaks of rage or panic.
Researchers have tried to identify the individual differences that make some people more vulnerable than others. Michigan State University psychologist Naomi Breslau and her collaborators conducted a study on 1,007 members of a health maintenance organization in Detroit.26,27 Thirty-nine percent of them had been exposed to traumatic events, and 24 percent of those developed PTSD. Those who developed PTSD after the trauma were more likely to have had early separation from parents, a family history of anxiety, or preexisting anxiety or depression.
The researchers then did something remarkable: they studied the same population again three years later. Nineteen percent had experienced a new traumatic event during the period, and 11 percent of those had developed PTSD. The strongest predictor of developing PTSD was a history of past exposure to traumatic events, and traumatic events were more likely to happen to people who had previously experienced something terrible. Such terrible events were more likely to happen to people with a tendency to neuroticism and extroversion, so those most vulnerable to bad feelings were also the most likely to experience trauma.28 Breslau and colleagues reviewed this and many other studies to find out who is most vulnerable to developing PTSD after a trauma. The strongest factor was lack of social support, followed by experiencing neglect or trauma in childhood.29
Are enduring changes after trauma useful or just a screw-up in the system? I doubt that PTSD is a useful adaptation in general. However, following the Smoke Detector Principle, it is easy to see how extreme defensive responses could be aroused normally by cues only distantly similar to those associated with a life-threatening situation. After nearly losing your life, general increased arousal is likely to be worthwhile despite its large costs. Hair-trigger startle responses can be useful, as can extreme fear when exposed to cues that indicate even a 1 in 1,000 chance that potentially fatal danger is present. People with PTSD know perfectly well that they are not still on a battlefield, but their bodies and minds respond as if they were. A book by Australian researcher Chris Cantor reviewed the evidence about whether this extraordinary hypersensitivity is just an abnormality or part of a useful adaptation with a terrible price of extreme false alarms, but it is hard to draw a firm conclusion.30
Generalized Anxiety Disorder
Generalized anxiety disorder (GAD) is about as far as you can get from PTSD and still have an anxiety disorder. Instead of symptoms tightly connected to a very specific event or danger, GAD consists of diverse worries and physical symptoms of anxiety. “Worry” doesn’t sound too serious, until you actually talk with people who suffer from GAD. To estimate its severity I ask, “What percent of your mental life is devoted to worry?” For many patients the response is “More than ninety percent, that’s all I think about.”
A typical patient with GAD worries about money, storms, health, children, and the security of employment and marriage. Things that most people would brush off become festering preoccupations. “I am only sixty-two. What happens if my company goes broke and I lose my insurance and I get sick before I am eligible for Medicare?” “What if my daughter plays in the backyard and a deer jumps the fence and she gets a tick bite and gets Lyme disease and I don’t notice the rash?” Their mental lives are a continual stream of “What if?” potential catastrophes. They also experience physical symptoms, especially muscle tension, fatigue, trembling, sweating, and bowel symptoms. Such symptoms themselves are a fine focus for worry.
The danger-monitoring system is set to a hair trigger in people with GAD. Their minds fill with dire fantasies. Pride and pleasure as a daughter sets off for prom night are displaced by visions of accidents or pregnancy. Instead of time to relax in those few extra minutes when a spouse arrives home late, there is only worry about accidents or heart attacks.
A fascinating recent finding is that genetic tendencies to GAD overlap strongly with those for depression.31 The specific responsible alleles have not been found, but relatives of people with GAD have an increased risk of both GAD and depression, and relatives of people with depression have an increased risk of depression and GAD. Both disorders reflect a state of caution in the face of adversity. Both may escalate because of vicious cycles instigated by evolved systems that make the systems more responsive after bad things happen.32
Many other psychiatric problems can also be viewed as excessive protective responses. Eating disorders arise from a desperate fear of obesity. Pathological jealousy arises from a fear that a partner will leave or be unfaithful. Paranoia arises from fears that others are plotting against you. Spending the right amount of energy on protection is wise, but many of us spend far too much, the Smoke Detector Principle notwithstanding.
What Should We Do Differently?
Understanding the evolutionary origins and functions of anxiety does not suggest a special evolutionary kind of treatment, but it nonetheless transforms treatment. In my early years of practice, I sympathized with my anxiety patients for having a disease. No matter how carefully I phrased it, that made many feel weak or flawed. When I instead began emphasizing that anxiety is a useful response that often goes overboard, many patients reported feeling normalized and empowered.
Women are twice as likely as men to have an anxiety disorder. Many explanations have been proposed based on hormones, brain mechanisms, and social forces, all of which suggest that there is something wrong with women. An evolutionary perspective flips the analysis on its head: women on average have about the right amount of anxiety for their own welfare; men have the right amount to maximize transmission of their genes, at a huge risk to their health.
Arguments about whether panic disorder, GAD, and social anxiety disorder are fundamentally the same or different are unnecessary; all are anxiety subtypes, each partially differentiated from ancestral precursor states to cope with dangers in different kinds of situations. Instead of seeking special explanations for why some people have more than one anxiety disorder, the associatio
n of multiple kinds of anxiety types makes sense in light of their common evolutionary origins. Instead of assuming that anxiety is always excessive, an evolutionary view calls attention to the Smoke Detector Principle and the need for research on hypophobia.
An evolutionary view also encourages setting aside abstract debates about whether anxiety disorders are mostly physical or mostly psychological and turning attention instead to a personalized assessment of all possible causes of an individual’s anxiety. Some patients have lifelong problems similar to those of their relatives. Others have no family history and no problems with anxiety, until some life event sets off a disorder. An evolutionary perspective also helps clinicians and patients put aside the misguided notion that treatment choices should be guided by beliefs about causes. Problems that arise mainly from genetic or physiological causes often respond well to psychological treatments. Problems induced by life situations often benefit from medications.
An evolutionary perspective also illuminates how treatments work. Antianxiety drugs do not correct a neurotransmitter deficit; they disrupt the anxiety system, just as aspirin disrupts fever and pain systems. Behavior therapy also changes the brain. It acts via mechanisms that evolved to adjust anxiety responses as environments become less or more dangerous. These mechanisms do not just reverse conditioning. Instead, exposure therapy creates new inhibitory impulses from the frontal lobes that descend and prevent anxiety signals from getting to consciousness.33 This is why stress can revive old unrelated fears. Pavlov conditioned dogs to fear a sound and then conditioned them to eliminate the fear. But after a flood nearly drowned the dogs in their cages, many showed a return of their fear.34
Good Reasons for Bad Feelings Page 10
