Editor's Note:
Mood disorders are the most prevalent of all mental disorders. Medscape Psychiatry & Mental Health Editor Robert Kennedy discusses the current issues in mood disorders with Canadian psychiatrist Pierre Blier, MD, PhD, Professor of Psychiatry, Institute of Mental Health Research, University of Ottawa, Ontario, Canada.
Medscape: Please tell us about some of your ideas and research in mood disorders over the last few years.
Pierre Blier, MD, PhD: I have been involved in the study of the mechanisms of antidepressant treatments for the past 25 years. My endeavors have been about trying to find out how medications work and how to make them work better and faster in the long run. This has been the focus of our attention.
Medscape: Have you focused on serotonin receptors, norepinephrine receptors, or both?
Dr. Blier: Initially, we focused on the serotonin system because we thought it was a major mechanism by which all these antidepressants could work. In recent years, we have concentrated on the norepinephrine system because it is also important in mediating the antidepressant response, and now we are at the point where we are looking at the interactions of the two systems.
Medscape: Michael Thase has done some interesting studies in the pooled analysis of the SSRIs vs SNRIs. Could you comment on that?
Dr. Blier: These were pivotal analyses that needed to be done on medications that acted on 1 system vs 2 systems to determine whether you are getting an additional benefit if you are targeting 2 systems. And clearly these meta-analyses have documented the superiority of the SNRIs.
Medscape: In terms of your own work, what population do you work with? Individuals with mild or severe depression? Inpatients or outpatients?
Dr. Blier: In general, our studies use outpatients with unipolar depression, generally in the moderate to severe range. It is in this range that you can better detect differences among treatments.
Medscape: Do you find that most patients have a mixture of symptoms or a variety of other comorbidities?
Dr. Blier: No, it is not difficult to find patients with pure unipolar major depression; however, if you mention anxiety, that is inherent to depression. Eighty percent of depressed patients will have significant levels of anxiety -- it is part of the syndrome.
Medscape: And the antidepressants act on the anxiety as well. Is that correct?
Dr. Blier: Yes, the SSRIs as well as the SNRIs are very effective in the treatment of anxiety as well.
Medscape: Have you also done research on OCD?
Dr. Blier: Yes I have, although from a very mechanistic point of view, as we were trying to clarify the mechanism of action of the SSRIs in depression, and of course they are the only medications that work in the treatment of OCD. What we did basically was instead of looking at brain structures in depression, we looked at brain structures involved in OCD in order to elucidate the actions of SSRIs. Of course these were laboratory studies. What we have put into evidence is that these medications actually enhance serotonin transmission in these brain regions, but it takes much longer than it does in the regions involved in depression. This is a very nice parallel that there is a much prolonged delay in onset of action in OCD vs depression.
Medscape: Is some of the newer research looking at faster-acting depressants?
Dr. Blier: Oh, absolutely. It has always been our goal in the treatment of depression to get people better faster. I think this is an achievable goal by really trying to clarify how medications work. Once we know exactly how they work, the goal is to achieve the same pharmacologic end point faster through different tools.
