It has long been recognized that people who feel depressed tend to think depressed thoughts. It is commonly assumed that a depressed mood somehow leads to cognitive symptoms. Cognitive theories of depression aim to explain why some people are more vulnerable to depression when confronted with negative events, whereas others suffer only mild short-term distress. Seen from the cognitive approach, the interpretation people give to their life experiences influences their vulnerability to depression, meaning that depressed cognition, cognitive distortions, and irrational beliefs produce the disturbances of mood characteristic of depression.

The American psychiatrist Aaron Beck is seen as the founder of cognitive therapy. He argues that depression is rooted in what he called a patient's "automatic thoughts"- that is, negative self-schemas organized around themes of failure inadequacy, loss, and worthlessness. All these personalized thoughts are triggered by particular stimuli that lead to emotional responses and they are seen as potential vulnerabilities for the onset of depression.

Beck's theory of depression has three components:

1. The Negative cognitive triad: depressed patients have negative views of the self, the world, and the future.
2. They have negative schemas triggered by negative life events (dysfunctional beliefs).
3. They engage in cognitive biases - also referred to as "irrational thinking."

Beck argues that negative schemas can develop because of family problems, social rejection by peers, poor school experiences or by having depressed members of the family or close social circle. These schema are activated in depressed people whenever they are in a situation which in any way resembles the situations in which the schema were created. Beck describes three typical schema that are characteristic of depressed people: an ineptness schema - that is, I always fail; a self-blame schema - that is, it is my fault for anything that doesn't work out; a negative self-evaluation schema - that is, I am worthless.

Beck also argues that there are several patterns of faulty thinking or cognitive biases that are typical in depressed patients.  These patterns are explained in the chart below.

In addition to Beck’s extensive notes on his patients over the course of his career, there are also several studies that support the theory that cognitive biases are linked to depression. Alloy et al. (1999) wanted to see if one’s thinking patterns could be used to predict the onset of depression. In order to do this, they carried out a longitudinal study in which they followed a randomly selected sample of young Americans for six years. As this was a prospective study, their thinking style was tested at the very beginning of the study. They were placed in either the “positive cognitive group” (low risk) or “the negative cognitive group” (high risk) based on a number of tests such as the Cognitive Style Questionnaire. After six years, the researchers found that only 1 percent of those in the positive thinking group had developed depression compared to 17 percent in the negative thinking group. The results indicate that there may be a link between negative cognitive style and the development of depression.

In another study, Joiner et al (1996) gave a questionnaire to university students before mid-term exams. Those who had negative thoughts before the exam and who ended up doing poorly showed an increase in depressive symptoms. However, those that did well, did not. This shows that patterns of cognition alone are not enough to lead to depression, but they must also be in response to environmental stimuli.

Overall, it is not clear if depression is caused by negative thinking patterns or if these patterns are merely the consequence of having depression. If a negative cognitive style causes depression then replacing negative cognitions with positive thinking patterns could improve the patient’s condition. This is exactly what CBT (cognitive-behavioural therapy) tries to do.

The role of rumination in depression

Dysfunctional beliefs and self-schemas may not be the only cognitive factors that lead to depression. Nolen-Hoeksema has found that women are more likely to amplify depression by ruminating about their feelings and their possible causes - that is, they think a lot about how they feel and try to understand the reasons they feel the way they do. In one study, Nolen-Hoeksema (2000) found that both men and women who ruminate more following the loss of loved ones are more likely to become depressed and to suffer longer and more severe depression than those who ruminate less. According to the researcher, rumination appears to more consistently predict the onset of depression rather than the duration, but rumination in combination with negative cognitive styles can predict the duration of depressive symptoms.

Recent brain research seems to support Nolen-Hoeksema’s theory. Farb et al (2011) showed 16 formerly depressed patients sad and neutral movie clips and tracked their brain activity using an fMRI. They compared this to 16 healthy controls. All participants filled out questionnaires measuring their adaptive as well as maladaptive cognitive modes in the face of emotional challenges. They also measured the severity of depression in the patients. The researchers calculated correlations between emotional reactivity (neural responses to sad vs. neutral film) in patients after the scanning and subsequent relapse status over an 18 month follow-up period. The prediction was that activity in the medial prefrontal cortex predicted relapse. The results supported the hypothesis: ten of the 16 patients had relapsed into depression during the 18-month follow-up period.

Faced with sadness, the relapsing patients showed more activity in a frontal region of the brain, known as the medial prefrontal gyrus. These responses were also linked to higher rumination: the tendency to think obsessively about negative events and occurrences. The healthy participants showed activity in the visual cortex.  

This study suggests that there are important differences in how formerly depressed people respond to emotional challenges that predict future well-being. Ruminating in order to analyze and interpret sadness may actually be an unhealthy reaction that can perpetuate the chronic cycle of depression. The researchers themselves argue that the study is limited in its ability to conclusively determine the neural predictors of depressive relapse due to a small sample size and a limited number of scans. It is important that the findings be replicated in order to determine their reliability. If more evidence is found that this pattern of thinking leads to depression, prevention strategies can be developed.  Modern research on mindfulness has shown that refocusing one’s attention may be an important way to fight depression.

 Teacher only box

You may want to show students the following video.

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Have students do a bit more research on the topic.  It is interesting to see the wide range of research that seems to have some contradictory results.  For example, this article shows that mindfulness and meditation may actually have a negative effect on people living with depression.

When considering why this makes sense, there are two different explanations - a cognitive and a biological explanation.  If we know that cortisol plays a role in depression, then any activity that lowers stress should, theoretically, be a treatment for depression.  In addition, if cognitive factors - such as rumination - play a role in depression, then "clearing one's mind" may have the effect of quieting the thinking pattern that contributes to the disorder.

Checking for understanding

Sociocultural approach to depression