Bipolar Disorder – A BRIDGE to nowhere?

Last August I blogged about a research paper that claimed that almost half of all people suffering from depression actually have features of bipolar disorder – including me: So Apparantly I’m Bipolar

It was called the BRIDGE study. I took issue with it for various reasons, including the fact that it counted as ‘bipolar features’ any periods of irritable or elevated mood, even if they were associated with drug treatment:

Under the new regime if you’ve ever been irritable, high, agitated or hyperactive, on antidepressants or not, you meet “Bipolar Specifier” criteria, so long as it was marked enough that someone else noticed it…

A cynic would say that this is a breathtaking piece of psychiatric marketing. You give people antidepressants, then you diagnose them with bipolar on the basis of their reaction to those drugs, thus justifying selling them yet more drugs.

The cynic would not be surprised to learn that this study was sponsored by pharmaceutical company Sanofi.

Now a crack team of psychiatrists have written a Letter to the Editor criticizing BRIDGE and they say… pretty much what I said: BRIDGE Study Warrants Critique. They do make a couple of new points also.

The 8 authors of the Letter include David Allen, David Healy, Peter Parry and Jon Jureidini, all major critical voices in psychiatry. However… while this A-Team make an excellent case that BRIDGE is a step in the direction of overdiagnosis and overtreatment of bipolar, they drop the ball slightly when they say:

The article concluded with an appeal to use “mood stabilizers,” presumably atypical antipsychotics, which are less efficacious than lithium. The sponsor has a medication in this class.

Sanofi does make the atypical antipsychotic amisulpiride, but it’s not generally referred to as a “mood stabilizer”, and I’m not sure why you’d assume that Sanofi had amisulpiride specifically in mind. The BRIDGE team exploit this in their rebuttal letter:

Allen et al cast unseemly aspersions that the BRIDGE study was a vehicle to promote sales of an antipsychotic drug sold by sanofi-aventis. sanofi-aventis has no antipsychotic with an indication for bipolar disorder. We know of no evidence that this was the case at any stage of development and execution of the BRIDGE study.

Maybe so, but as I said in my post, Sanofi also make some popular brands of valproate/valproic acid, a prototypical “mood stabilizer” which is widely used in bipolar disorder. I’d have said that was the more likely candidate…

Fundamentally, we know that Sanofi “was involved in the study design, conduct, monitoring, data analysis, and preparation of the report.” We also know that Sanofi is exists to make profit by selling drugs. So either Sanofi thought that this study would make them a profit eventually, by selling more drugs… or they threw money and time at this for no commercial reason. Hmm.

The reply concludes with the frankly bizarre statement that:

Allen et al view their position as part of a “debate” about the “ever-widening bipolar spectrum.” We consider data, not debates, as central to the progress in the scientific understanding of mood disorders…

But science is a debate about data. Data by themselves are just numbers; to be useful, they must be interpreted, and scientific debates aim at arriving at such interpretations. No-one is questioning the BRIDGE data as such, we’re questioning what it means.

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