by Michael D. Anestis, M.S.
When we think about psychotherapy, many of us assume that each session marks a step in a steady improvement in symptoms. Others assume that most sessions are essentially meaningless, but that a "eureka" moment occurs and suddenly the client is free of his or her symptoms. As it turns out, there has been a fairly substantial amount of research on this topic, particularly as it relates to the treatment of depression. The work of Tony Tang of Northwestern University has been especially important in this area and, today, we will be discussing a number of papers that he and his colleagues have published over the past 15 years.
Tang's work appears to have been motivated at least in part by a highly influential study published by Ilardi and Craighead in 1994. That study, which looked at cognitive behavioral therapy (CBT) for depression, found that 60-70% of symptom improvement in CBT for depression occurred within the first four weeks. The authors believed that cognitive techniques, which were originally theorized by Aaron Beck to be the reason why the therapy is so successful, are not utilized extensively during these early sessions and that, as such, cognitive theory was in question. Tang and others looked at this work, noted its importance, and recognized some serious weaknesses. Rather than simply criticize the study, however, they instead examined work that directly tested what they believed were flaws in Ilardi and Craighead's (1994) work. In 1990, DeRubeis and Feeley examined the amount of time spent on cognitive techniques throughout CBT and found that therapists spent as much time on such approaches in the second session as they did in any other session later in therapy. In other words, the evidence is that cognitive techniques are, in fact, a pivotal component of early CBT for depression. In their own review of the literature, Tang and DeRubeis (1999) noted that, in CBT efficacy studies (including those analyzed by Ilardi and Craighead, 1994), therapists tend to administer two sessions per week for the first four weeks, meaning that eight weeks worth of therapy occurs within the first month. This, of course, renders the argument that not enough time has passed for cognitive techniques to be taught and for those techniques to have an impact quite empty.
Anyway, having established these points, Tang set off on a line of research that sought to look at how therapy impacts depression symptoms, how often clients experience sudden gains in treatment, and how such gains are related to long term outcomes. In perhaps the most influential of these studies, another paper he co-authored with DeRubeis in 1999, they found that out of 61 clients, 24 experienced sudden gains, with the median 50% falling between the fifth and tenth sessions. On average, sudden gains - which refer to improvement in symptoms from one session to the next - involved a decrease in Beck Depression Inventory (BDI) scores of 11.2 points. To put this in perspective, the average overall improvement in treatment for all clients was 15.4 and the average for those who experienced sudden gains was 21.8. In other words, clients who experienced sudden gains, on average, experienced 51% of their total symptom reduction in one between-session surge!
When you hear something like that - the sudden disappearance of the majority of a depressed client's symptoms - you might assume this represents some sort of fleeting improvement. This, however, was not the case. Even when the authors considered a 50% return of symptoms to be a full reversal (e.g., client with a BDI score of 30 improves to 20 but then falters and returns to 25), only 4 clients who experienced sudden gains ultimately experienced reversals during therapy and 79% experienced a full recovery.
Taking this point even further, Tang and DeRubeis (1999) found that clients who experienced sudden gains in treatment for their depression had significantly better outcomes than those who did not experience sudden gains (average post-treatment BDI score of 5.9 compared to 16.8) even though both groups were equally depressed pre-treatment. At 6 and 18 month follow-up, clients who had experienced sudden gains in treatment still exhibited significantly greater improvement.
Tang and DeRubeis (1999) next asked what accounted for sudden changes in therapy. After all, it is important to know what components of therapy account for clients improving. They found that a greater degree of cognitive change (e.g., implementation of cognitive restructuring) was experienced in the session immediately preceding a sudden gain than in other sessions. Importantly, therapeutic alliance was not higher in the session preceding sudden gains than in other sessions, meaning that a strong alliance could not completely account for the outcome. Immediately following a sudden gain, therapeutic alliance was stronger, indicating that the view of the strength of the therapeutic relationship in CBT might hinge upon the degree to which therapy is having its intended effects.
In 2005, Tang, DeRubeis, Beberman, and Pham published a study in which they examined these same questions in three different variations of CBT. Their results were entirely consistent with everything reported above, meaning that their initial results were not a fluke occurrence. In 2007, Tang, DeRubeis, Hollon, Amsterdam, and Shelton looked at these same variables over a longer time frame: 2 years. They found that only one-third of individuals who experienced sudden gains relapsed in the two years following therapy and that these individuals had a 74% lower relapse rate than did individuals who did not experience sudden gains.
This work is very informative, in that it clearly demonstrates the power of sudden gains in treatment for depression, but everything we have discussed thus far has focused on CBT. As it turns out though, Tang has not limited all of his work to this one particular treatment approach. In 2002, Tang, Luborsky, and Andrusyna published a study that examined whether sudden gains also occur in supportive-expressive psychotherapy (SE) for depression. In this study, the authors found that sudden gains do, in fact, occur in SE, and that they exhibit a similar magnitude, impact a similar percentage of clients, and occur at approximately the same point of therapy as sudden gains in CBT. The difference, however, is that sudden gains in SE were significantly less stable, with a substantially greater proportion of clients experiencing reversals of gains during therapy. In a follow-up, published by Adnrusyna, Luborsky, Pham, and Tang in 2006, the authors found that sudden gains in SE were preceded by greater accuracy in therapist interpretations. Not surprisingly, as SE does not emphasize such skills, cognitive changes did not precede sudden gains in this approach. Alliance was nearly significantly higher immediately preceding sudden gains, but not quite.
These last two studies tell us a couple of important things. First of all, sudden gains in depression treatment are not unique to CBT. Secondly, sudden gains in CBT are much more stable than in SE, indicating that a sudden gain in CBT is significantly more meaningful. Third, the reasons for sudden gains are different in different forms of therapy and the specific cognitive skills utilized in CBT might be particularly important for effecting long term stable changes in symptoms.
Summary
I realize that I covered a large number of studies in this article, so let me try to break the information down in a more digestible format. Essentially, the work of Tony Tang and his colleagues over the past 15 years has shown us that some individuals receiving CBT to treat their depression experience sudden gains in treatment that account for more than half of their overall improvement. These sudden gains are not merely momentary surges of positive feelings though. In fact, studies have shown that sudden gains in treatment result in better treatment outcomes that are maintained for years following the end of therapy. Importantly, although some argue that a strong alliance between the therapist and the client is the most important factor in determining outcome, the results of these studies paint a different picture. The degree to which a client in CBT demonstrates changes in cognitive skills (e.g., the ability to challenge unrealistically negative thoughts with evidence) appears to be a more important factor in prompting a sudden gain, which is exactly what Aaron Beck anticipated when he developed CBT in the first place. Finally, these studies also showed us that sudden gains in depression symptoms can also occur in SE, but that these gains are much less likely to be sustained and are not prompted by the same types of changes that lead to sudden gains in CBT.
Having gone over all of this information, part of me fears that some readers might come away from this thinking something along the lines of:
- "I did not experience a sudden gain in treatment...does that mean I am going to relapse?"
- "I am in treatment now and have not experienced a sudden gain...does that mean treatment won't work for me?"
- "My clients do not experience these sudden gains...is this research useless?"
Please remember, not everybody follows the same pattern and the authors are not saying that an individual must have a sudden gain to recover from depression and fend off relapse. They are simply noting a robust pattern that has occurred numerous times across different samples. There is variability and error in any statistical relationship and these numbers and studies are intended as a guide to trends, not a description of what will happen for each individual. Of course, variability and error do not diminish the importance and utility of this research by any stretch. Information like this helps us to develop a greater understanding of which therapies are most effective for particular symptoms and how it is that they lead to such improvements.
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If you would like to learn more about depression and the use of CBT in its treatment, we recommend the following items, each of which is available in our online store for scientifically-based psychological resources:
- Cognitive Therapy of Depression
by Aaron Beck, John Rush, Brian Shaw, and Gary Emery
- Treatment Plans and Interventions for Depression and Anxiety Disorders
by Robert Leahy and Stephen Holland
by Robert Leahy
- Feeling Good: The New Mood Therapy Revised and Updated
by David Burns
- The Feeling Good Handbook
by David Burns
- Handbook of Depression, Second Edition
by Ian Gotlib and Constance Hammen
Mike Anestis is a doctoral candidate in the clinical psychology department at Florida State University
