by Michael D. Anestis, M.S.
Depression is a cruel and greedy intruder, not only for those who battle its symptoms, but also for their loved ones. It brings seemingly unending waves of negative emotions, it robs people of their ability to experience joy, it disrupts sleep and eating, and it steals hope. For some, it tragically culminates in loss of life due to suicide. For all of these reasons and more, many individuals have devoted their lives to studying and treating depression with the hope of helping people avoid such pain.
One of the many things we have learned through research is that depression is episodic. In other words, it will show up, hang around for a while, disappear, come back, and repeat this pattern again and again if left to its own devices. There are several empirically supported treatments like cognitive-behavioral therapy (CBT) and interpersonal psychotherapy (IPT) that have been shown to successfully treat symptoms and, in large part, prevent them from coming back, but the episodic nature of depression remains an important consideration. For one thing, past episodes of depression are one of the strongest predictors of future episodes of depression. Adolescents with a past history of depression, for example, are more likely to develop future depressive episodes than are adolescents with no such history (Garber, Kriss, Koch, & Lindholm, 1988). Because of findings like this, Lewinsohn, Steinmetz, Larson, and Franklin (1981) developed the "scar hypothesis," which states that depressive episodes cause individuals to develop characteristics that linger even after an episode has ended, thus leaving them vulnerable to future depression.
The idea of psychological scars is compelling. It gives us a poignant and familiar image - physical scars - as a guide to help us conceptualize an abstract concept like mental illness. It allows us to compare emotional struggles with familiar physical sensations and provides us with a way to envision the impact of depression on those who have experienced its binding grip. The question, however, is whether this compelling hypothesis is supported by empirical evidence. Along these lines, several researchers have attempted to study whether "scars" indeed are formed in response to depressive episodes and, if so, what those scars actually represent.
In one study of 352 grade school children, Nolen-Hoeksema, Girgus, and Seligman (1992) assessed depressive symptoms and attributional style repeatedly over a five year period and found that, in children who became depressed during the study, pessimistic attributional style increased in severity and remained elevated after depression symptoms subsided. As such, they concluded that a pessimistic attributional style may represent a "scar" of depression. In a separate study, Rohde, Lewinsohn, and Seeley (1994) examined depression and a variety of other variables in 45 adolescents at two time points separated by one year. These researchers found that depressive symptoms, internalizing behavior problems, stressful life events, and excessive emotional reliance on others might represent "scars" of depression.
Today, I would like to discuss a newer study on this same phenomenon, published in 2007 in the Journal of Consulting and Clinical Psychology by Christopher Beevers, Paul Rohde, Eric Stice, and Susan Nolen-Hoeksema. The authors of this newer study - several of whom were also authors on the two studies cited above - mentioned that, while those earlier works were impressive in a number of ways, they also had important limitations that prevent a full understanding of whether or not any of the variables above actually represent "scars." For one thing, the Nolen-Hoeksema et al (1992) study relied on self-report measures and, as such, no diagnostic information was available. Additionally, the Rohde et al (1994) study only had two time points and a period of one-year, which prevented any assessment of whether or not the "scars" were actually present before depression onset and whether they faded with time after depression remitted.
In this newer study, Beevers and colleagues (2007) followed 496 female adolescents over a 7-year period. Each year, participants took part in structured diagnostic interviews and filled out a series of questionnaires. The authors identified 49 participants from this group who experienced their first ever depressive episode during the study and, in their analyses, they compared these individuals to 98 individuals with no history of depression prior to or during the experiment. Importantly, the authors only included depressed individuals who did not meet criteria for depression one year, experienced their first depressive episode the next year, and did not meet criteria for depression the year after that. The central aim of the study was to determine if the onset of an individual's first ever depressive episode resulted in an increase of particular variables that would remain elevated even after depression remitted, thereby serving as "scars" of depression.
The authors' findings were quite interesting. When comparing the depressed group to the non-depressed group, each participant had three years of data. For individuals in the depressed group, this meant they were looking at data from the year before depression, the year of depression, and the year after depression. For the non-depressed group, they were simply looking at three consecutive years. Along these lines, Beevers and colleagues (2007) found that the depressed group was more likely to have sub-threshold depressive symptoms in years 1 and 3 than were the non-depressed group; however, only 7% of the individuals in the depressed group had sub-threshold symptoms during those years. In other words, although a small minority of individuals in the depressed group had symptoms of depression in the years preceding and following their depressive episode, most individuals did not follow that pattern.
Beevers and his co-authors (2007) next looked at a series of 13 other variables to see if they might serve as "scars." The results indicated that none of these variables fit the pattern of emerging in response to the initial depressive episode and lingering in the year after depression had remitted. That being said, they did find compelling evidence that these 13 variables serve a different types of risk factors for depression.
Negative emotionality, rumination, and social maladjustment were all elevated prior to the onset of the initial depressive episode, became more severe during the depressive episode, then returned to their Year 1 levels after depression remitted. As such, the authors referred to these variables as "exacerbated risk factors." In other words, they were not "scars" of depression because they were there before depression. Instead, they were risk factors for the development of depression and were, in turn, impacted by the depression while it was ongoing. Depressive symptoms followed a similar pattern. For those who experienced lingering depressive symptoms after their actual depressive episode, those same symptoms tended to be present prior to the depressive episode as well. Most individuals who experienced sub-threshold depression, however, did not experience a later depressive episode.
Low self-esteem, low parental support, low levels of peer support, substance use, antisocial behavior, bulimic symptoms, and negative life events all served as "chronic risk factors." In other words, individuals in the depressed group had higher levels of each of these risk factors prior to, during, and after depressive episodes and those who were depressed exhibited elevations of each of these factors prior to their depressive episodes, not just after them. As such, it appears that while these variables predict vulnerability to depression, they do not serve as "scars" in that they do not emerge in response to depression.
Looking at all of these findings, the evidence does not seem to support the idea that depression leaves "scars" that account for the episodic nature of the illness. Does this mean that depression does not have an impact on the lives of individuals after the symptoms fade? Absolutely not. But it does mean that many of those impacts were already established prior to the depressive episode as well and that, while individuals are more likely to reflect back upon their depressed days as a starting point for these variables, this might not accurately reflect how things unfolded.
There are some important limitations to this study that must be considered. The authors noted that their sample consisted entirely of adolescent girls. As such, the findings can not necessarily be generalized to boys or populations in different age groups. Additionally, the authors could not possibly measure every possible variable that could serve as a "scar" of depression. As such, although they did not find any variables that fit that pattern, this does not mean that there are not other variables that would. The authors also only looked at individuals for whom depression lasted a year or less, so it is possible that "scars" only exist for individuals that experience a longer course of illness. Finally, although the authors used impressive longitudinal data, they could not experimentally manipulate many of the variables and, as such, they could not conclusively determine whether any of the risk factors actually caused depression. Correlation, after all, does not equal causation.
Despite these limitations, this study offered us a lot of important information. Primarily, despite the philosophical appeal of the "scar hypothesis," there is no evidence supporting that the theory is valid. Instead, there appears to be a wide variety of risk factors for depression, some of which become worse during depressive episodes and then return to their initial levels once depression remits. Along these lines, there are many different paths to depression for adolescent girls, but no evidence that, once they experience their first depressive episode, they are likely to develop "scars" from the experience that, in turn, leave them responsible to future depressive episodes. Their vulnerability to future depression, which is a very real and well-established phenomenon, is instead better accounted for by variables that were already present before they ever experienced depression.
As I said in the opening of this article, depression is a dark and disheartening experience for everyone involved. Our intense and entirely understandable impulse to grasp the meaning of depression can leave us latching onto ideas that make intuitive sense, regardless of whether or not there is any evidence supporting the validity of those ideas. This one study by no means indicates that the "scar hypothesis" is incorrect; however, to this point, there is more evidence contradicting than supporting the idea of "scars." The better way to think about the phenomenon appears to be that depression is the result of many different vulnerabilities and that treatments must target these vulnerabilities in order to reduce risk because, left without intervention, they are likely to linger and continue to lead to problematic outcomes.
If you would like to learn more about depression, we recommend the following resources, all of which are available through our online store:
- Handbook of Depression, Second Edition
by Constance Hammen and Ian Gotlib
- Skills Training Manual for Diagnosing and Treating Chronic Depression: Cognitive Behavioral Analysis System of Psychotherapy by James McCollough
- Cognitive Therapy of Depression
by Aaron Beck, John Rush, Brian Shaw, and Gary Emery
- Feeling Good: The New Mood Therapy Revised and Updated
by David Burns
Mike Anestis is a doctoral candidate in the clinical psychology department at Florida State University
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