15-11 How do major depressive disorder, persistent depressive disorder, and bipolar disorder differ?

Most of us will have some direct or indirect experience with depression. If you are like many college students, at some time during this year—more likely the dark months of winter than bright days of summer—you may experience some of depression’s symptoms. You might feel deeply discouraged about the future, dissatisfied with your life, or socially isolated. You may lack the energy to get things done or even to force yourself out of bed; be unable to concentrate, eat, or sleep normally; or even wonder if you would be better off dead. Perhaps academic success came easily to you before, but now you find that disappointing grades jeopardize your goals. Maybe social stress, such as loneliness, feeling you are the target of prejudice, or experiencing a romantic breakup, have plunged you into despair. And perhaps low self-esteem increases your brooding, worsening your self-torment (Sowislo & Orth, 2012). Likely you think you are more alone in having such negative feelings than you really are (Jordan et al., 2011). In one national survey of American collegians, 31 percent said they had at some time in the past year, “felt so depressed that it was difficult to function” (ACHA, 2009). Misery has more company than most suppose.

Joy, contentment, sadness, and despair exist at different points on a continuum, points at which any of us may find ourselves at any given moment. To feel bad in reaction to profoundly sad events is to be in touch with reality. In such times, there is an up side to being down. Sadness is like a car’s low-fuel light—a signal that warns us to stop and take appropriate measures. Biologically speaking, life’s purpose is not happiness but survival and reproduction. Coughing, vomiting, swelling, and pain protect the body from dangerous toxins. Similarly, depression resembles a sort of psychic hibernation: It slows us down, defuses aggression, helps us let go of unattainable goals, and restrains risk taking (Andrews & Thomson, 2009a,b; Wrosch & Miller, 2009). When we grind temporarily to a halt and reassess our life, as depressed people do, we can redirect our energy in more promising ways (Watkins, 2008). We may also make better decisions. Even mild sadness can improve people’s recall, make them more discerning, and help them make complex decisions (Forgas, 2009). It can also help them process and recall faces more accurately (Hills et al., 2011). There is sense to suffering.

But sometimes this response, taken to an extreme, can become seriously maladaptive and signal a disorder. The difference between a blue mood after bad news and a depression-related disorder is like the difference between gasping for breath after a hard run and being chronically short of breath.

In this section, we consider three disorders in which depression impairs daily living:

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Major depressive disorder occurs when at least five signs of depression last two or more weeks (TABLE 15.5). The symptoms must cause near-daily distress or impairment and not be attributable to substance use or another medical or mental illness.

To sense what major depression feels like, suggest some clinicians, imagine combining the anguish of grief with the sluggishness of bad jet lag. If stress-related anxiety is a “crackling, menacing brushfire,” noted biologist Robert Sapolsky (2003), “depression is a suffocating heavy blanket thrown on top of it.”

Adults diagnosed with persistent depressive disorder (also called dysthymia) experience a mildly depressed mood more often than not for two years or more (American Psychiatric Association, 2013). They also display at least two of the following symptoms:

With or without therapy, episodes of major depression usually end, and people temporarily or permanently return to their previous behavior patterns. However, some people rebound to, or sometimes start with, the opposite emotional extreme—the hyperactive, overly talkative, wildly optimistic state of mania. If depression is living in slow motion, mania is fast forward. Alternating between depression and mania signals bipolar disorder.

Adolescent mood swings, from rage to bubbly, can, when prolonged, lead to a bipolar diagnosis. Between 1994 and 2003, diagnoses of bipolar disorder swelled. U.S. National Center for Health Statistics annual physician surveys revealed an astonishing 40-fold increase in bipolar disorder diagnoses in those 19 and under—from an estimated 20,000 to 800,000 (Carey, 2007; Flora & Bobby, 2008; Moreno et al., 2007). Americans are twice as likely as people of other countries to have ever had a diagnosis of bipolar disorder (Merikangas et al., 2011). The new popularity of the diagnosis, given in two-thirds of the cases to boys, has profited companies whose drugs are prescribed to lessen mood swings. Under the new DSM-5 classifications, the number of child and adolescent bipolar diagnoses will likely decline, because some individuals with emotional volatility will be diagnosed with disruptive mood dysregulation disorder (Miller, 2010).

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During the manic phase, people with bipolar disorder typically have little need for sleep. They show fewer sexual inhibitions. Their positive emotions persist abnormally (Gruber, 2011; Gruber et al., 2013). Their speech is loud, flighty, and hard to interrupt. They find advice irritating. Yet they need protection from their own poor judgment, which may lead to reckless spending or unsafe sex. Thinking fast feels good, but it also increases risk taking (Chandler & Pronin, 2012; Pronin, 2013).

For some people suffering depressive disorders or bipolar disorder, symptoms may have a seasonal pattern. Depression may regularly return each fall or winter, and mania (or a reprieve from depression) may dependably arrive with spring. For many others, winter darkness simply means more blue moods. When asked “Have you cried today?” Americans have agreed more often in the winter (TABLE 15.6).

In milder forms, mania’s energy and flood of ideas fuel creativity. George Frideric Handel, who may have suffered from a mild form of bipolar disorder, composed his nearly four-hour-long Messiah (1742) during three weeks of intense, creative energy (Keynes, 1980). Robert Schumann composed 51 musical works during two years of mania (1840 and 1849) but none during 1844, when he was severely depressed (Slater & Meyer, 1959). Those who rely on precision and logic, such as architects, designers, and journalists, suffer bipolar disorder less often than do those who rely on emotional expression and vivid imagery (Ludwig, 1995). Composers, artists, poets, novelists, and entertainers seem especially prone (Jamison, 1993, 1995; Kaufman & Baer, 2002; Ludwig, 1995). Indeed, one analysis of over a million individuals showed that the only psychiatric condition linked to working in a creative profession was bipolar disorder (Kyaga et al., 2013). As one staff member said of the great leader Winston Churchill, “He’s either on the crest of the wave, or in the trough” (Ghaemi, 2011).

It is as true of emotions as of everything else: What goes up comes down. Before long, the elated mood either returns to normal or plunges into a depression. Though bipolar disorder is much less common than major depressive disorder, it is often more dysfunctional, claiming twice as many lost workdays yearly (Kessler et al., 2006). It afflicts adult men and women about equally.

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15-12 How can the biological and social-cognitive perspectives help us understand depressive disorders and bipolar disorder?

In thousands of studies, psychologists continue to accumulate evidence to help explain why people have depressive disorders and bipolar disorder and to design more effective ways to treat and prevent them. Here, we focus primarily on depressive disorders. One research group summarized the facts that any theory of depression must explain, including the following (Lewinsohn et al., 1985, 1998, 2003):

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Armed with these points of understanding, today’s researchers propose biological and cognitive explanations of depression, often combined in a biopsychosocial perspective.

Genetic Influences Depressive disorders and bipolar disorder run in families. As one researcher noted, emotions are “postcards from our genes” (Plotkin, 1994). The risk of major depression and bipolar disorder increases if you have a parent or sibling with the disorder (Sullivan et al., 2000). If one identical twin is diagnosed with major depressive disorder, the chances are about 1 in 2 that at some time the other twin will be, too. This effect is even stronger for bipolar disorder: If one identical twin has it, the chances are 7 in 10 that the other twin will at some point be diagnosed similarly—even if the twins were raised apart (DiLalla et al., 1996). Among fraternal twins, the corresponding odds are just under 2 in 10 (Tsuang & Faraone, 1990). Summarizing the major twin studies (see FIGURE 15.6), one research team estimated the heritability of major depressive disorder (the extent to which individual differences are attributable to genes) at 37 percent (Bienvenu et al., 2011).

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To tease out the genes that put people at risk for depression, some researchers have turned to linkage analysis. First, geneticists find families in which the disorder appears across several generations. Next, the researchers examine DNA from affected and unaffected family members, looking for differences. Linkage analysis points them to a chromosome neighborhood; “A house-to-house search is then needed to find the culprit gene” (Plomin & McGuffin, 2003). Such studies reinforce the view that depression is a complex condition. Many genes work together, producing a mosaic of small effects that interact with other factors to put some people at greater risk. If culprit gene variations can be identified—so far, chromosome 3 genes have been implicated in separate British and American studies (Breen et al., 2011; Pergadia et al., 2011)—they may open the door to more effective drug therapy.

The Depressed Brain Scanning devices open a window on the brain’s activity during depressed and manic states. One study gave 13 elite Canadian swimmers the wrenching experience of watching a video of the swim in which they failed to make the Olympic team or failed at the Olympic games (Davis et al., 2008). Functional MRI scans showed the disappointed swimmers experiencing brain activity patterns similar to those of patients with depressed moods.

Many studies have found diminished brain activity during slowed-down depressive states, and more activity during periods of mania (FIGURE 15.7). The left frontal lobe and an adjacent brain reward center become more active during positive emotions, (Davidson et al., 2002; Heller et al., 2009; Robinson et al., 2012). In studies of depressed people, MRI scans also found their frontal lobes were smaller than normal (Coffey et al., 1993; Ribeiz et al., 2013; Steingard et al., 2002). Other studies show that the hippocampus, the memory-processing center linked with the brain’s emotional circuitry, is vulnerable to stress-related damage.

Neuroscientists have also discovered altered brain structures in people with bipolar disorder. One analysis discovered decreased white matter and enlarged fluid-filled ventricles (Arnone et al., 2009).

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Neurotransmitter systems also influence depressive disorders and bipolar disorder. Norepinephrine, which increases arousal and boosts mood, is scarce during depression and overabundant during mania. (Drugs that decrease mania reduce norepinephrine.) Many people with a history of depression also have a history of habitual smoking (Pasco et al., 2008). Once the urge to smoke is ignited, depression also makes it more difficult to quit (Hitsman et al., 2012). This may indicate an attempt to self-medicate with inhaled nicotine, which can temporarily increase norepinephrine and boost mood (HMHL, 2002).

Researchers are also exploring a second neurotransmitter, serotonin (Carver et al., 2008). One well-publicized study of New Zealand young adults found that the recipe for depression combined two necessary ingredients—significant life stress plus a variation of a serotonin-controlling gene (Caspi et al., 2003; Moffitt et al., 2006). Depression arose from the combination of an adverse environment plus a genetic susceptibility, but not from either alone. But stay tuned: The story of gene-environment interactions is still being written, as other researchers debate the reliability of this result (Caspi et al., 2010; Culverhouse et al., 2013; Karg et al., 2011; Munafò et al., 2009; Uher & McGuffin, 2010).

Drugs that relieve depression tend to increase norepinephrine or serotonin supplies by blocking either their reuptake (as Prozac, Zoloft, and Paxil do with serotonin) or their chemical breakdown. Repetitive physical exercise, such as jogging, reduces depression because it increases serotonin, which affects mood and arousal (Airan et al., 2007; Ilardi, 2009; Jacobs, 1994). In one study, running for two hours increased brain activation in regions associated with euphoria (Boecker et al., 2008). To run away from a bad mood, you can use your own two feet.

Nutritional Effects What’s good for the heart is also good for the brain and mind. People who eat a heart-healthy “Mediterranean diet” (heavy on vegetables, fish, and olive oil) have a comparatively low risk of developing heart disease, stroke, late-life cognitive decline, and depression—all of which are associated with inflammation (Dowlati et al., 2010; Psaltopoulou et al., 2013; Sánchez-Villegas et al., 2009; Tangney et al., 2011). Excessive alcohol use also correlates with depression—mostly because alcohol misuse leads to depression (Fergusson et al., 2009).

Biological influences contribute to depression, but in the nature–nurture dance, our actions also play a part. Diet, drugs, stress, and other life experiences lay down epigenetic marks, which are often organic molecules. These molecular tags attach to our chromosomes and turn certain genes on or off. Animal studies suggest that epigenetic influences may play a long-lasting role in depression (Nestler, 2011).

Thinking matters, too. The social-cognitive perspective explores how people’s assumptions and expectations influence what they perceive. Depressed people view life through the dark glasses of low self-esteem (Kuster et al., 2012; Sowislo & Orth, 2012). Their intensely negative assumptions about themselves, their situation, and their future lead them to magnify bad experiences and minimize good ones (Wenze et al., 2012). Listen to Norman, a Canadian college professor, recalling his depression:

I [despaired] of ever being human again. I honestly felt subhuman, lower than the lowest vermin. Furthermore, I was self-deprecatory and could not understand why anyone would want to associate with me, let alone love me…. I was positive that I was a fraud and a phony and that I didn’t deserve my Ph.D. I didn’t deserve to have tenure; I didn’t deserve to be a Full Professor…. I didn’t deserve the research grants I had been awarded; I couldn’t understand how I had written books and journal articles…. I must have conned a lot of people. (Endler, 1982, pp. 45–49)

Expecting the worst, depressed people’s self-defeating beliefs and their negative explanatory style feed depression’s vicious cycle.

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Negative Thoughts and Negative Moods Interact Self-defeating beliefs may arise from learned helplessness, the hopelessness and passive resignation animals and humans learn when they experience uncontrollable painful events. Learned helplessness has been found more often in women than in men, and women may respond more strongly to stress (Hankin & Abramson, 2001; Mazure et al., 2002; Nolen-Hoeksema, 2001, 2003). For example, 38 percent of women and 17 percent of men entering American colleges and universities have reported feeling at least occasionally “overwhelmed by all I have to do” (Pryor et al., 2006). (Men reported spending more time in “light anxiety” activities such as sports, TV watching, and partying, possibly avoiding activities that might make them feel overwhelmed.) This gender difference may help explain why, beginning in their early teens, women have been nearly twice as vulnerable to depression. Susan Nolen-Hoeksema (2003) related women’s higher risk of depression to what she described as their tendency to ruminate or overthink. Rumination—staying focused on a problem (thanks to the continuous firing of a frontal lobe area that sustains attention)—can be adaptive (Altamirano et al., 2010; Andrews & Thomson, 2009a,b). But relentless, self-focused rumination can divert us from thinking about other life tasks, and can increase negative moods (Kuppens et al., 2010; Kuster et al., 2012).

Even so, why do life’s unavoidable failures lead only some people to become depressed? The answer lies partly in their explanatory style—who or what they blame for their failures. Think of how you might feel if you failed a test. If you can externalize the blame (“What an unfair test!”), you are more likely to feel angry. If you blame yourself, you probably will feel stupid and depressed.

So it is with depressed people, who often explain bad events in terms that are stable (“It’s going to last forever”), global (“It’s going to affect everything I do”), and internal (“It’s all my fault”) (FIGURE 15.8). Depression-prone people respond to bad events in an especially self-focused, self-blaming way (Mor & Winquist, 2002; Pyszczynski et al., 1991; Wood et al., 1990a,b). When they describe themselves, their brains activate in a region that processes self-relevant information (Sarsam et al., 2013). Their self-esteem is also more plastic—it climbs with praise and plummets with threats (Butler et al., 1994).

Pessimistic, overgeneralized, self-blaming attributions may create a depressing sense of hopelessness (Abramson et al., 1989; Panzarella et al., 2006). As Martin Seligman has noted, “A recipe for severe depression is preexisting pessimism encountering failure” (1991, p. 78). What then might we expect of new college students who are not depressed but do exhibit a pessimistic explanatory style? In one study, Lauren Alloy and her colleagues (1999) monitored students every 6 weeks for 2.5 years. Among those identified as having a pessimistic thinking style, 17 percent had a first episode of major depression, as did only 1 percent of those who began college with an optimistic thinking style.

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Why is depression so common among young Westerners? Seligman (1991, 1995) has pointed to the rise of individualism and the decline of commitment to religion and family, which forces young people to take responsibility for failure or rejection. In non-Western cultures, where close-knit relationships and cooperation are the norm, major depression is less common and less tied to self-blame over personal failure (Ferrari et al., 2013; WHO, 2004a). In Japan, for example, depressed people instead tend to report feeling shame over letting others down (Draguns, 1990a).

Critics note a chicken-and-egg problem nesting in the social-cognitive explanation of depression. Which comes first? The pessimistic explanatory style, or the depressed mood? Certainly, the negative explanations coincide with a depressed mood, and they are indicators of depression. But do they cause depression, any more than a speedometer’s reading 70 mph causes a car’s speed? Before or after being depressed, people’s thoughts are less negative. Perhaps a depressed mood triggers negative thoughts. If you temporarily put people in a bad or sad mood, their memories, judgments, and expectations suddenly become more pessimistic. Memory researchers understand this tendency to recall experiences that are consistent with one’s current good or bad mood. They call it state-dependent memory.

Depression’s Vicious Cycle Depression is both a cause and an effect of stressful experiences that disrupt our sense of who we are and why we are worthy human beings. Such disruptions can lead to brooding, which amplifies negative feelings. Being withdrawn, self-focused, and complaining can in turn elicit rejection (Furr & Funder, 1998; Gotlib & Hammen, 1992). One study set up brief phone conversations between participants and people who did or did not have depression. After the conversation, participants could accept or reject the other person. The result? They rejected depression-prone people more often. The participants also noted that they felt more depressed, anxious, and hostile after speaking with depressed people (Coyne, 1976). Indeed, people in the throes of depression are at high risk for divorce, job loss, and other stressful life events. Weary of the person’s fatigue, hopeless attitude, and lethargy, a spouse may threaten to leave or a boss may begin to question the person’s competence. (This provides another example of genetic-environmental interaction: People genetically predisposed to depression more often experience depressing events.) Rejection and depression feed each other. Misery may love another’s company, but company does not love another’s misery.

We can now assemble some of the pieces of the depression puzzle (FIGURE 15.9): (1) Negative, stressful events interpreted through (2) a ruminating, pessimistic explanatory style create (3) a hopeless, depressed state that (4) hampers the way the person thinks and acts. This, in turn, fuels (1) negative, stressful experiences such as rejection. Depression is a snake that bites its own tail.

None of us are immune to the dejection, diminished self-esteem, and negative thinking brought on by rejection or defeat. Even small losses can temporarily sour our thinking. In one study, researchers studied some avid Indiana University basketball fans who seemed to regard the team as an extension of themselves (Hirt et al., 1992). After the fans watched their team lose or win, the researchers asked them to predict the team’s future performance and their own. After a loss, the morose fans offered bleaker assessments not only of the team’s future but also of their own likely performance at throwing darts, solving anagrams, and getting a date. When things aren’t going our way, it may seem as though they never will.

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It is a cycle we can all recognize. Bad moods feed on themselves: When we feel down, we think negatively and remember bad experiences. Abraham Lincoln was so withdrawn and brooding as a young man that his friends feared he might take his own life (Kline, 1974). Poet Emily Dickinson was so afraid of bursting into tears in public that she spent much of her adult life in seclusion (Patterson, 1951). As their lives remind us, people can and do struggle through depression. Most regain their capacity to love, to work, and even to succeed at the highest levels.

15-13 What factors increase the risk of suicide, and what do we know about nonsuicidal self-injury?

Each year over 800,000 despairing people worldwide will elect a permanent solution to what might have been a temporary problem (WHO, 2014). For those who have been depressed, the risk of suicide is at least five times greater than for the general population (Bostwick & Pankratz, 2000). People seldom commit suicide while in the depths of depression, when energy and initiative are lacking. The risk increases when they begin to rebound and become capable of following through.

Comparing the suicide rates of different groups, researchers have found

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Social suggestion may trigger suicide. Following highly publicized suicides and TV programs featuring suicide, known suicides increase. So do fatal auto and private airplane “accidents.” One six-year study tracked suicide cases among all 1.2 million people who lived in metropolitan Stockholm at any time during the 1990s (Hedström et al., 2008). Men exposed to a family suicide were 8 times more likely to commit suicide than were nonexposed men. That phenomenon may be partly attributable to family genes. But shared genetic predispositions cannot explain why men exposed to a co-worker’s suicide were 3.5 times more likely to commit suicide, compared with nonexposed men.

Because suicide is so often an impulsive act, environmental barriers (such as jump barriers on high bridges and the unavailability of loaded guns) can save lives (Anderson, 2008). Common sense may suggest that a determined person will simply find another way to complete the act, but such restrictions give time for self-destructive impulses to subside.

Suicide is not necessarily an act of hostility or revenge. People—especially older adults—may choose death as an alternative to current or future suffering, a way to switch off unendurable pain and relieve a perceived burden on family members. Suicidal urges typically arise when people feel disconnected from others and a burden to them, or when they feel defeated and trapped by an inescapable situation (Joiner, 2010; Taylor et al., 2011). Thus, suicide rates increase a bit during economic recessions (Luo et al., 2011). Suicidal thoughts also may increase when people are driven to reach a goal or standard—to become thin or straight or rich—and find it unattainable (Chatard & Selimbegovic´, 2011).

In hindsight, families and friends may recall signs they believe should have forewarned them—verbal hints, giving possessions away, or withdrawal and preoccupation with death. To judge from surveys of 84,850 people across 17 nations, about 9 percent of people at some point in their lives have thought seriously of suicide. About 3 in 10 of those who think about it will actually attempt suicide (Nock et al., 2008). Only about 1 in 25 Americans die in that attempt (AAS, 2009). Of those who die, one-third had tried to kill themselves previously. Most discussed it beforehand. So, if a friend talks suicide to you, it’s important to listen and to direct the person to professional help. Anyone who threatens suicide is at least sending a signal of feeling desperate or despondent.

Nonsuicidal Self-Injury Suicide is not the only way to send a message or deal with distress. Some people, especially adolescents and young adults, may engage in nonsuicidal self-injury (NSSI) (FIGURE 15.10). These people hurt themselves in various ways. They may cut or burn their skin, hit themselves, insert objects under their nails or skin, or tattoo themselves (Fikke et al., 2011). Though painful, these self-injuries are not fatal. People who engage in NSSI tend to be less able to tolerate emotional distress. They are extremely self-critical and often have poor communication and problem-solving skills (Nock, 2010). Why do they hurt themselves? Through NSSI they may

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Does NSSI lead to suicide? Usually not. Those who engage in NSSI are typically suicide gesturers, not suicide attempters (Nock & Kessler, 2006). Suicide gesturers engage in NSSI as a desperate but non-life-threatening form of communication or when they are feeling overwhelmed. Nevertheless, NSSI is considered a risk factor for future suicide attempts (Wilkinson & Goodyer, 2011). If people do not find help, their nonsuicidal behavior may escalate to suicidal thoughts and, finally, to suicide attempts.

LEARNING OBJECTIVES

RETRIEVAL PRACTICE Take a moment to answer each of these Learning Objective Questions (repeated here from within this section). Then click the 'show answer' button to check your answers. Research suggests that trying to answer these questions on your own will improve your long-term retention (McDaniel et al., 2009).

15-11 How do major depressive disorder, persistent depressive disorder, and bipolar disorder differ?

15-12 How can the biological and social-cognitive perspectives help us understand depressive disorders and bipolar disorder?

15-13 What factors increase the risk of suicide and what do we know about nonsuicidal self-injury?

TERMS AND CONCEPTS TO REMEMBER

RETRIEVAL PRACTICE Match each of the terms on the left with its definition on the right. Click on the term first and then click on the matching definition. As you match them correctly they will move to the bottom of the activity.

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