Prepare for a really dorky blog entry.
I was very struck by Kendler, Kuhn, & Prescott's 2004 article--not necessarily because of their conclusions about risk factors for depressive episodes but because of how they got there. In other words, I appreciated their approach to various statistical issues, especially model building and the use of raw probabilities. Admittedly, I am still a quantitative infant, but I particularly appreciated their deliberate decision to compare additive versus multiplicative models of risk. It is often tempting to try to fit any dataset to a linear model, not for any theoretical reason, but simply for reasons of convenience. Much can be gained, however, from considering the implications of fitting data to different mathematical functions; in this case, for instance, fitting a multiplicative model of risk suggests processes that differ in important ways from the ones that would operate in an additive model of risk. Just because linear models are easy to construct and analyze does not mean that they are the best way to understand our data!
I also appreciated Kendler et al.'s discussion of their decision to use raw probabilities as opposed to transforming them, perhaps to log(raw probability). Using a logarithmic transformation may indeed have made the process of statistical analysis easier but it also would have disguised one of the most interesting features of these data, which is the nonlinear relationship between risk of a depressive episode and contextual threat X neuroticism. I agree with the "public health argument" and I also think that it would have been much more difficult to interpret log(hazard ratio) than it is to interpret the raw probabilities. Despite the statistical convenience that transformation to a log scale can provide, it can lead to results that are difficult to interpret. Here, sticking with the raw probabilities makes the patterns Kendler et al. wish to highlight much more clear.
P.S. Jim--you wanted me to remind you to get me the reference(s) on doing meta-analyses of single-case studies.
Monday, October 29, 2007
Sunday, October 21, 2007
me and my incoherent brain
While reading Voelker's brief article on proposed links between sleep disruptions and depression in college students, I flashed back to vivid memories of college friends dealing with depression who felt unable to get up in the morning despite multiple alarm clocks--who stayed asleep in bed until 4 or 5 pm, missing all their classes. Their problems with depression seemed intimately tied to abnormal sleep patterns and an inability to establish a healthy sleep-wake rhythm. Sleep problems can be devastating to individuals' daily functioning (lost jobs, failed classes...), so I'd be interested to know the statistics on abnormal sleep patterns in persons with depression. [Armitage's observation of poor coherence during the sleep of some individuals with depression was certainly provocative, but I'd be interested to see the findings replicated.]
Thinking along these lines, it seems to me that incorporating sleep hygiene goals in a behavioral activation therapy program for depression could be highly useful. Bootzin & Epstein discuss establishing appropriate discriminative stimuli for falling asleep by reserving the bed and bedroom for sleep only; along with establishing appropriate cues for sleep, they recommend certain daytime activities as well: avoiding naps, engaging in light, regular exercise, and exposing oneself to bright light. It seems to me that the stimulus control instructions would mesh well with goals for behavioral activation; developing simple goals early in therapy such as "I will not stay in bed for more than 15 minutes after waking in the morning" and "I will not use my bed for purposes other than sleeping (or sexual activity)" and moving on to more challenging goals such as "I will avoid naps" and "I will spend 15 minutes a day doing [fill in form of light exercise here]" as therapy progresses could help the client both to "activate" and to resolve sleep disturbances--which, in turn, would likely assist the client in activating yet further.
Certainly, resolving sleep problems will not automatically resolve depression, but it seems to me that these issues may, for many individuals, have a reciprocal relationship; anxiety or catastrophizing may feed insomnia, but then insomnia may further feed anxiety. Certain depressed persons might be predisposed to certain kinds of sleep disturbances, and these sleep disturbances may lead to impaired performance at school or at work--which may worsen a depressed individual's perception of their own efficacy. It seems to me that it would only make sense to tackle these problems together. I'd be interested to see any research that tackled this question empirically.
Thinking along these lines, it seems to me that incorporating sleep hygiene goals in a behavioral activation therapy program for depression could be highly useful. Bootzin & Epstein discuss establishing appropriate discriminative stimuli for falling asleep by reserving the bed and bedroom for sleep only; along with establishing appropriate cues for sleep, they recommend certain daytime activities as well: avoiding naps, engaging in light, regular exercise, and exposing oneself to bright light. It seems to me that the stimulus control instructions would mesh well with goals for behavioral activation; developing simple goals early in therapy such as "I will not stay in bed for more than 15 minutes after waking in the morning" and "I will not use my bed for purposes other than sleeping (or sexual activity)" and moving on to more challenging goals such as "I will avoid naps" and "I will spend 15 minutes a day doing [fill in form of light exercise here]" as therapy progresses could help the client both to "activate" and to resolve sleep disturbances--which, in turn, would likely assist the client in activating yet further.
Certainly, resolving sleep problems will not automatically resolve depression, but it seems to me that these issues may, for many individuals, have a reciprocal relationship; anxiety or catastrophizing may feed insomnia, but then insomnia may further feed anxiety. Certain depressed persons might be predisposed to certain kinds of sleep disturbances, and these sleep disturbances may lead to impaired performance at school or at work--which may worsen a depressed individual's perception of their own efficacy. It seems to me that it would only make sense to tackle these problems together. I'd be interested to see any research that tackled this question empirically.
Saturday, October 6, 2007
good storytellers
Despite Jim's disclaimer in class last week, I really enjoyed this week's readings and they went by quickly. I was particularly interested by Jacobson, Martell, and Dimidjian's 2001 article on behavioral activation treatment for depression. Their focus on action, rather than cognition, intrigued me. "One of the primary goals of presenting the BA model," they state, "is to dispel the myth that changes in mood need to occur before changes in behavior" (p. 260). I put a little exclamation point next to this statement on my paper copy, because in making this claim, Jacobson et al. draw upon a large body of social psychology research that supports the notion that behaviors have the ability to change cognitions just as much as, if not more than, cognitions have the ability to change behaviors. If forced, for example, to choose between two equally appealing alternatives, we later devalue the one we did not choose and increase our evaluation of the one we did choose. A study I particularly like that illustrates our behaviors' ability to drive our judgment is one in which participants were asked to engage in an excruciatingly boring task for a long period of time. (For the life of me, I cannot remember who did this study!) Once the task had been completed, researchers either offered the participants $1 or $15 to tell the future participants that the task had been interesting. Participants who received $15 did so, but later rated the study as boring. Participants who received $1 also told others the study was interesting, but when privately rating the study, said they had actually found it interesting. Presumably, they could not justify lying about the study for just $1, and so explained their behavior by coming to believe that they had actually found the repetitive task interesting! This and other similar studies suggest that while we don't always know the reason for our behaviors, we're very good at coming up with plausible explanations after the fact.
Although we would like to believe that we are perfectly rational creatures, oftentimes our self-stories are used not to guide our behaviors but to make sense of what we do. By encouraging depressed individuals to engage in personally reinforcing activities, BA uses behaviors as a guide to change cognitions (i.e., "if I am choosing to get out of bed and engage in this activity, then I must be feeling more energetic"). I doubt that this would work if goals were not worked out collaboratively; if the therapist were more active-directive, I imagine that the client would then be able to attribute their actions to the "orders" of the therapist, and would consequently not derive as much benefit. I therefore see the program's emphasis on helping the client to select activities that they personally find reinforcing to be a plus. Getting the client to make choices about goals and carry them out independently as homework drives them to ascribe their positive behaviors to their own internal states rather than to the dictates of the therapist.
Overall, I found theirs to be an intriguing and potentially very useful perspective on the treatment of depression. Looking forward to hearing from everyone else on this!
Although we would like to believe that we are perfectly rational creatures, oftentimes our self-stories are used not to guide our behaviors but to make sense of what we do. By encouraging depressed individuals to engage in personally reinforcing activities, BA uses behaviors as a guide to change cognitions (i.e., "if I am choosing to get out of bed and engage in this activity, then I must be feeling more energetic"). I doubt that this would work if goals were not worked out collaboratively; if the therapist were more active-directive, I imagine that the client would then be able to attribute their actions to the "orders" of the therapist, and would consequently not derive as much benefit. I therefore see the program's emphasis on helping the client to select activities that they personally find reinforcing to be a plus. Getting the client to make choices about goals and carry them out independently as homework drives them to ascribe their positive behaviors to their own internal states rather than to the dictates of the therapist.
Overall, I found theirs to be an intriguing and potentially very useful perspective on the treatment of depression. Looking forward to hearing from everyone else on this!
Monday, October 1, 2007
a born demander
Is there any meaningful difference between REBT and other forms of CBT? Engels, Garnefski, and Diekstra (1993) seem as though they'd like to tackle this question ("The findings of ...quantitative reviews lead to the conclusion that cognitive-behavioral therapies show the highest overall effect sizes...of all treatment modalities under study, but the degree to which RET contributed to this result is unclear" [p. 1083]) but they find themselves unable to address this question due to lack of sufficient data. Instead, Engels et al. end up comparing RET to placebo, systematic desensitization, and combination treatments--a strategy that seems to me less than useful. Comparing RET to placebo tells us little about the therapy's incremental validity, while comparing it to "combination treatments" (i.e. RET plus "behavioral therapy such as group systematic desensitization, self-control desensitization, or behaviorally oriented assertiveness training" (p. 1085)) and to systematic desensitization seems too much like comparing the same thing. Desensitization is cropping up everywhere here!
I encountered an anecdote about Albert Ellis on Wikipedia (I know, I know) relating how, as a young man, he overcame his shyness around women by approaching 100 women in the Bronx Botanical Gardens and engaging them in conversation. This desensitization procedure that he developed for himself at the age of 19 seemed like a foreshadowing of his later formation of a therapeutic strategy that he described as "unusually forceful and emotive and uniquely behavioral with its emphasis on in vivo desensitization" (p. 154). (Italics mine). Given the role of desensitization in REBT, systematic desensitization, and these combination treatments, it seems like a finding of no significant difference among these conditions tells us very little--we might have expected that methods utilizing exposure & desensitization would be similar in their effects.
What would be really interesting to know would be the answer to that first question--is there any meaningful difference between REBT and other forms of CBT? Engels et al. describe RET as "distinguished from other CBT methods especially in its therapeutic goal: the client's achievement of a new philosophical outlook" (p. 1083). But does helping clients to achieve a more existentialist worldview produce any incremental improvement over any other form of CBT? Are there clients for whom a therapist's assumption "that imperatives lead to needless disturbance" would prove unhelpful (p. 157)? Is any form of "must," too strongly adhered to, considered unhealthy, or would only certain classes of "musts" qualify? I suppose I'm thinking here of dealing with highly religious clients. Would the REBT therapist classify the "musts" of the religion as too absolutistic to be healthy? Would any orthodox client be seen as necessarily unhealthy for holding such dogmatic beliefs? I don't entirely understand the full nature of REBT--what the essential components of it are as opposed to what are simply more related to Ellis's personal therapeutic style. I'm looking forward to discussing this further in class.
P.S. Interesting excerpts from Ellis's Overcoming Resistance: A Rational Emotive Behavior Therapy Integrated Approach:
Shame-attacking exercise
(And for Jim:)
On using obscenities
I encountered an anecdote about Albert Ellis on Wikipedia (I know, I know) relating how, as a young man, he overcame his shyness around women by approaching 100 women in the Bronx Botanical Gardens and engaging them in conversation. This desensitization procedure that he developed for himself at the age of 19 seemed like a foreshadowing of his later formation of a therapeutic strategy that he described as "unusually forceful and emotive and uniquely behavioral with its emphasis on in vivo desensitization" (p. 154). (Italics mine). Given the role of desensitization in REBT, systematic desensitization, and these combination treatments, it seems like a finding of no significant difference among these conditions tells us very little--we might have expected that methods utilizing exposure & desensitization would be similar in their effects.
What would be really interesting to know would be the answer to that first question--is there any meaningful difference between REBT and other forms of CBT? Engels et al. describe RET as "distinguished from other CBT methods especially in its therapeutic goal: the client's achievement of a new philosophical outlook" (p. 1083). But does helping clients to achieve a more existentialist worldview produce any incremental improvement over any other form of CBT? Are there clients for whom a therapist's assumption "that imperatives lead to needless disturbance" would prove unhelpful (p. 157)? Is any form of "must," too strongly adhered to, considered unhealthy, or would only certain classes of "musts" qualify? I suppose I'm thinking here of dealing with highly religious clients. Would the REBT therapist classify the "musts" of the religion as too absolutistic to be healthy? Would any orthodox client be seen as necessarily unhealthy for holding such dogmatic beliefs? I don't entirely understand the full nature of REBT--what the essential components of it are as opposed to what are simply more related to Ellis's personal therapeutic style. I'm looking forward to discussing this further in class.
P.S. Interesting excerpts from Ellis's Overcoming Resistance: A Rational Emotive Behavior Therapy Integrated Approach:
Shame-attacking exercise
(And for Jim:)
On using obscenities
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