Quantitative Psychological Theory and Musings

Showing posts with label major depression. Show all posts
Showing posts with label major depression. Show all posts

Monday, March 1, 2010

The Unmeasured Self

I was watching a discussion this morning on youtube titled The Role of Psychotherapy in the Age of Neuroreceptors and Genes, and I have some thoughts.  First though, I'd like to offer a context. 

Imagine you went to your family doctor complaining of adominal pain.  Your doctor refers you to an oncologist. The oncologist has just diagnosed you with a form of cancer that has an 18% fatality rate.  It can also lead to increased risks for a host of other health problems short of death, such as cardiovascular diseases, reduced immune responding, and a general lethargy that could affect both your professional and personal lives. 

He based his diagnosis on a family history and some rather personal questions about your lifestyle and habits, including a few questions about your medical history.  He started explaining the treatment process, when you interrupt him with a question.  You ask him if he will utilize more precise diagnostics, like various scanning technologies such as MRIs.  He tells you that they are unnecessary and that he is sure enough about your diagnosis to to begin treatment. 

Treatment will involve a painless, weekly procedure that the doctor says is often effective, though different patients are more responsive to certain doctors than others.  After asking him how you'll know your getting better, he tells you that he'll chiefly base your treatment progress assessment on how you say you're feeling and whether you think it's working. 

Would you feel comfortable with this diagnostic and treatment approach?  Yet, this is exactly what psychotherapists offer their patients with major depressive disorder, which is fatal in about 18% of cases and can greatly contribute to the other maladies mentioned above, among many others.  There is often not even a paper and pencil assessment offered during diagnosis, and there is usually no attempt at objective within-patient measurements of progress during treatment.

I'm not bashing psychotherapists here and I do acknowledge that widely known research demonstrates some effectiveness for psychotherapy in the aggregate.  But still,  how is the above situation acceptable?  Is there an alternative?

I think there is.  Other than advanced brain scans, which are currently expensive, but offer much hope in the future, a behavioral economic approach can be helpful.  Since depression involves low moods, the implications of which have been described in previous posts, the resultant shift to lower risk aversion could certainly provide a definitive, quantifiable measure of progress.

This can be done in a number of ways, but to begin, you can measure the loss tolerance of patients seeking reward, such as in contests with monetary prizes.  There can be opportunites to both win or lose money, with the patient keeping any earnings.  This is an approach very widely used in psychological and microeconomic experiments.  To note, of course changes in net personal income and assets will have to be controlled for, with the gains and losses in constant proportion. 

To complement this approach, the rates of substitution between different options can be measured, to determine consistency with the more direct measure of risk attitudes, as can the  ability to delay gratification and accept sooner losses.

There are also various ways to measure relative and absolute mood levels by recording behavioral investment, revealed as energy expenditure to obtain a given amount of reinforcement(pleasure).  For example, energy expenditure can be measured with respirometers, heart rate monitors, etc.  More energy will be expended- per-unit-gained as mood increases.  This is similar to the determination in economics that marginal utility must meet marginal costs.

I personally favor the last approach, as it is more direct and requires controlling fewer variables, but I'm not sure if non-physicians are allowed to use such diagnostic techniques.  The former approaches involving money are awkward, given the treatment context.

There are still other approaches, such as measuring stress hormones in saliva or examining asymmetrical EEG data, but these are also expensive, though certainly cheaper than MRIs and other brain scans.

Of course, with all of these approaches, stable baselines must be established to measure progress against.

So, there are conceivable ways for psychotherapists to demonstrate the effectiveness of their treatments in each individual and I hope more research will go into such approaches.  The question is, will the therapists want to use them?