42-2 How can the biological and social-cognitive perspectives help us understand major depressive disorder and bipolar disorder?

From thousands of studies of the causes, treatment, and prevention of major depressive disorder and bipolar disorder, researchers have pulled out some common threads. Here, we focus primarily on major depressive disorder. Any theory of depression must explain at least the following (Lewinsohn et al., 1985, 1998, 2003):

BEHAVIORS AND THOUGHTS CHANGE WITH DEPRESSION. People trapped in a depressed mood become inactive and feel alone, empty, and without a meaningful future (Bullock & Murray, 2014; Smith & Rhodes, 2014). They attend more selectively to negative aspects of their environments and situations (Peckham et al., 2010). They recall negative information. And they expect negative outcomes (my team will lose, my grades will fall, my love will fail). When the depression lifts, these behaviors and thoughts disappear. Nearly half the time, people with depression also have symptoms of another disorder, such as anxiety or substance abuse.

DEPRESSION IS WIDESPREAD. Worldwide, 300 million people suffer major depressive or bipolar disorder (Global, 2015). Depression is found worldwide. This suggests that depression’s causes must also be common.

WOMEN’S RISK OF MAJOR DEPRESSIVE DISORDER IS NEARLY DOUBLE MEN’S. In 2009, when Gallup pollsters asked more than a quarter-million Americans if they had ever been diagnosed with depression, 13 percent of men and 22 percent of women said Yes (Pelham, 2009). When Gallup asked Americans if they had experienced sadness “during a lot of the day yesterday,” 17 percent of men and 28 percent of women answered Yes (Mendes & McGeeney, 2012). This depression gender gap—with U.S. women experiencing depression 1.7 times more often than men (CDC, 2014)—has been found worldwide (FIGURE 42.1). The trend begins in adolescence; preadolescent girls are not more depression-prone than boys are (Hyde et al., 2008).

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The depression gender gap fits a bigger pattern: Women are generally more vulnerable to disorders involving internalized states, such as depression, anxiety, and inhibited sexual desire. Women experience more situations that may increase their risk for depression, such as receiving less pay for equal work, juggling multiple roles, and caring for children and elderly family members (Freeman & Freeman, 2013). Men’s disorders tend to be more external—alcohol use disorder, antisocial conduct, lack of impulse control. When women get sad, they often get sadder than men do. When men get mad, they often get madder than women do.

MOST MAJOR DEPRESSIVE EPISODES END ON THEIR OWN. Therapy often helps and tends to speed recovery. But even without professional help, most people recover from major depression and return to normal. The black cloud of depression comes and, a few weeks or months later, it often goes. For about half of those people, it eventually returns (Burcusa & Iacono, 2007; Curry et al., 2011; Hardeveld et al., 2010). The condition will be chronic for about 20 percent (Klein, 2010).

On average, a person with major depressive disorder today will spend about three-fourths of the next decade in a normal, nondepressed state (Furukawa et al., 2009). An enduring recovery is more likely if the first episode strikes later in life, there were few previous episodes, the person experiences minimal stress, and there is ample social support (Belsher & Costello, 1988; Fergusson & Woodward, 2002; Kendler et al., 2001).

STRESSFUL EVENTS OFTEN PRECEDE DEPRESSION. About one person in four diagnosed with depression has been brought down by a significant loss or trauma, such as a loved one’s death, a ruptured marriage, a physical assault, or a lost job (Kendler et al., 2008; Monroe & Reid, 2009; Orth et al., 2009; Wakefield et al., 2007). Moving to a new culture can also increase depression, especially among younger people who have not yet formed their identities (Zhang et al., 2013). One long-term study tracked rates of depression in 2000 people (Kendler, 1998). Among those who had experienced no stressful life event in the preceding month, the risk of depression was less than 1 percent. Among those who had experienced three such events in that month, the risk was 24 percent. For some, grappling with life’s minor daily stressors can also negatively affect mental health. People who overreacted to minor stressors, such as a broken appliance, were more often depressed 10 years later (Charles et al., 2013).

WITH EACH NEW GENERATION, DEPRESSION STRIKES EARLIER (NOW OFTEN IN THE LATE TEENS) AND AFFECTS MORE PEOPLE, WITH THE HIGHEST RATES AMONG YOUNG ADULTS IN DEVELOPED COUNTRIES. This trend has been reported in Canada, England, France, Germany, Italy, Lebanon, New Zealand, Puerto Rico, Taiwan, and the United States (Collishaw et al., 2007; Cross-National Collaborative Group, 1992; Kessler et al., 2010; Twenge et al., 2008). In one study of Australian adolescents, 12 percent reported symptoms of depression (Sawyer et al., 2000). Most hid it from their parents, almost 90 percent of whom perceived their depressed teen as not suffering depression. In North America, young adults are three times more likely than their grandparents to report having recently—or ever—suffered depression.

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The increased risk among young adults appears partly real, but it may also reflect cultural differences between generations. Today’s young people are more willing to talk openly about their depression. We also tend to forget many negative experiences over time, so older generations may overlook depressed feelings they had in earlier years.

Depression is a whole-body disorder. It involves genetic predispositions and biochemical imbalances, as well as negative thoughts and a gloomy mood.

GENES AND DEPRESSION Major depressive disorder and bipolar disorder run in families. The risk of major depressive disorder 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 42.2), 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).

Emotions are “postcards from our genes” (Plotkin, 1994). To tease out the genes that put people at risk for depression, researchers may use linkage analysis. First, geneticists find families in which the disorder appears across several generations. Next, the researchers look for differences in DNA from affected and unaffected family members. 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 the culprit gene variations can be identified, 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. During depression, brain activity slows; during mania, it increases (FIGURE 42.3 below). 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).

At least two neurotransmitter systems are at work during the periods of brain inactivity and hyperactivity that accompany major depressive disorder and bipolar disorder. Norepinephrine, which increases arousal and boosts mood, is scarce during depression. Norepinephrine is overabundant during mania. Drugs that decrease mania reduce norepinephrine.

Serotonin is also scarce or inactive during depression (Carver et al., 2008). Drugs that relieve depression tend to increase serotonin or norepinephrine 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 by increasing serotonin (Airan et al., 2007; Ilardi et al., 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.

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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, partly because depression can increase alcohol use 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, molecular genetic tags that can turn certain genes on or off. Animal studies suggested 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. Many depressed people see life through the dark glasses of low self-esteem (Kuster et al., 2012; Sowislo & Orth, 2012). They have intensely negative views of themselves, their situation, and their future. 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 … 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 magnify bad experiences and minimize good ones (Wenze et al., 2012). Their self-defeating beliefs and negative explanatory style feed depression’s vicious cycle.

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, who may respond more strongly to stress (Hankin & Abramson, 2001; Mazure et al., 2002; Nolen-Hoeksema, 2001, 2003). Do you agree or disagree that you “at least occasionally feel overwhelmed by all I have to do”? In a survey of women and men, 38 percent of women, but only 17 percent of men, agreed (Pryor et al., 2006).

Why are women 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 can be adaptive when it helps us focus intently on a problem, thanks to the continuous firing of an attention-sustaining frontal lobe area (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).

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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 blame someone else (“What an unfair test!”), you are more likely to feel angry. If you blame yourself, you probably will feel stupid and depressed.

When bad events happen, depression-prone people tend to blame themselves (Mor & Winquist, 2002; Pyszczynski et al., 1991; Wood et al., 1990a,b). As FIGURE 42.4 illustrates, they explain bad events in terms that are stable (“I’ll never get over this”), global (“I can’t do anything right”), and internal (“It’s all my fault”). Their explanations are pessimistic, overgeneralized, self-focused, and self-blaming. When they describe themselves, their brains show extra activity in a region that processes self-relevant information (Sarsam et al., 2013). The result may be 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? Lauren Alloy and her colleagues (1999) monitored 349 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.

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? The negative explanations coincide with a depressed mood, and they are indicators of depression. (Before or after being depressed, people’s thoughts are less negative.) But do negative thoughts cause depression, any more than a speedometer’s reading 70 mph causes a car’s speed? 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—a phenomenon that memory researchers call state-dependent memory.

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Cultural forces may also nudge people toward or away from depression. 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 depressive disorder is less common and less tied to self-blame over personal failure (Ferrari et al., 2013; WHO, 2004). In Japan, for example, depressed people instead tend to report feeling shame over letting others down (Draguns, 1990a).

DEPRESSION’S VICIOUS CYCLE No matter which comes first, rejection and depression feed each other. Depression is both a cause and an effect of stressful experiences that disrupt our sense of who we are and why we are worthy. Such disruptions can lead to brooding, which is rich soil for growing negative feelings. And that negativity—being withdrawn, self-focused, and complaining—can by itself cause others to reject us (Furr & Funder, 1998; Gotlib & Hammen, 1992). Indeed, people deep in depression are at high risk for divorce, job loss, and other stressful life events. Weary of the person’s fatigue, hopeless attitude, and negativity, a spouse may threaten to leave, or a boss may begin to question the person’s competence. New losses and stress then plunge the already-depressed person into even deeper misery. Misery may love another’s company, but company does not love another’s misery.

We can now assemble pieces of the depression puzzle (FIGURE 42.5): (1) Stressful events interpreted through (2) a brooding, negative explanatory style create (3) a hopeless, depressed state that (4) hampers the way the person thinks and acts. These thoughts and actions, in turn, fuel (1) stressful experiences such as rejection. Depression is a snake that bites its own tail.

It is a cycle we can all recognize. When we feel down, we think negatively and remember bad experiences. Britain’s Prime Minister Winston Churchill called depression a “black dog” that periodically hounded him. Abraham Lincoln was so withdrawn and brooding as a young man that his friends feared he might take his own life (Kline, 1974). 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.

42-3 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 with unemployment during economic recessions (DeFina & Hannon, 2015; Reeves et al., 2014). 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 & Selimbegović, 2011).

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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. For young adults who have previously attempted suicide, the risk of suicide increases seven-fold, with the greatest risk in the ensuing three years (Al-Sayegh et al., 2015). Most will have discussed it beforehand.

How to be helpful to someone who is talking suicide. How should we respond to someone who says, for example, “I wish I could just end it all” or “I hate my life; I can’t go on”?

If people write such things online, you can contact the safety teams at various social media websites. Facebook, Twitter, Instagram, YouTube, and Tumblr all allow you to anonymously report someone’s suicidal expressions. In response, the site’s safety team will, if it concurs, send the writer an e-mail with a link to a counselor at the U.S. National Suicide Prevention Lifeline (1-800-273-TALK) or its counterpart in other countries.

If a friend or family member talks suicide, you can:

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 42.6). 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? Reinforcement processes are at work (Bentley et al., 2014). 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 suicidal thoughts and future suicide attempts (Dickstein et al., 2015; Wilkinson & Goodyer, 2011). If people do not find help, their nonsuicidal behavior may escalate to suicidal thoughts and, finally, to suicide attempts.