Thursday, December 30, 2010

How easy is it to treat depression?

The latest blog entry from APA's Healthy. Healthy Lives., besides making the misleading statement that antidepressants work by increasing the amount of serotonin between nerve cells, also gives the wrong impression that depression can be readily treated. The blog makes out that there are lots of options to try, so if you just keep making changes of medication everything will be alright.

I don't want to appear pessimistic about the outcome of treatment for depression. However, the reality is not as simple as the blogger makes out. Some people fail to respond to treatment and some relapse after responding. Over 6 months, maybe, about half of people do quite well, a third have a fluctuating course and 1 in 9 remain unwell (Mulder et al, 2006). Of those who are doing quite well at 6 months, maybe about half relapse in the following year (but a third of those depressed at 6 months recover) (Mulder et al, 2009).

Over the long-term, recurrence is high. Figures in studies vary from 40-85%. If about a quarter of people are improved by treatment, there's a quarter of people who do not have good outcomes (Hughes & Cohen, 2009).  Even if there's a clinical improvement, this does not necessarily  mean there's been a social recovery (Kennedy et al, 2007). Many patients still report residual symptoms despite apparently successful treatment (Fava et al, 2007).

Outcomes for non-drug treated samples are not necessarily any worse over the long-term (Hughes & Cohen, 2009). Doctors do not generally tell patients about the small effect size and substantial non-response rate of antidepressants for fear of undermining the effectiveness of medication. The serotonin imbalance theory is used as a means of encouraging patients to take their medication, which is why the Healthy Minds. Health Lives. blog mentions it.

The role of psychiatry is to give hope to depressed people. It is also to be honest with them about the cause of their problems and the appropriate treatment. Patients are able to understand that the 'chemical imbalance theory' is only a theory. What they find more difficult to appreciate is why they are told that this theory has been proven, when this is clearly not the case. They may also struggle when antidepressants may not give the simple and easy answer they have been led to expect.


Steindór J. Erlingsson said...

The latest challenge to the chemical imbalance theory appeared last month in V. Krishnan and E.J. Nestler's review article "Linking Molecules to Mood: New Insight Into the Biology of Depression" (American Journal of Psychiatry, 167, 1305–1320). They state that after more than a decade of various studies "there is little evidence to implicate true deficits in serotonergic, noradrenergic, or dopaminergic neurotransmission in the pathophysiology of depression" (p. 1306).

I think it is unethical of psychiatrists perpetuate this story as it gives the false impression that naive reductionism can explain depression (or other mental disorders). This does not only affect consumers and how they perceive their problems, as policy makers are also influenced by this appealing but untrue story.

Altostrata said...

Much of the so-called relapse is actually withdrawal syndrome, which can last for months or years.

Medicine's assumptions about withdrawal syndrome are based on anedoctal evidence (Haddad 2001) and the opinions of a U.S. "expert" committee underwritten in 1997 by Lilly and 2006 by Wyeth.

The observations of "relapse" after discontinuation of antidepressants have led to the dictum that depression is a chronic disease with high rates of relapse.

In other words, nothing that medicine thinks it knows about antidepressants and depression may be true.