Posted by Cam W. on October 13, 2000, at 23:39:26
In reply to Q. for CAM W. re risperdal vs. zyprexa, posted by anita on October 13, 2000, at 23:00:20
> Hi Cam,
>
> Some time ago you wrote a post about how risperidone may affect right-brain dysfunction, and zyprexa left-brain dysfunction. Do you know what this means exactly in terms of depression?
>
> I'd like to try adding on a small dose of one of the new antipsychotics (to zoloft and lamictal), theoretically for the 5HT2A antagonism. From what I've read, it seems that while risperidone has a higher affinity for 5HT2A, zyprexa actually tends to be more helpful for depression. Also, I've read that seroquel is not a good add-on for depression. Can you tell me what you think about this? My unresolved depressive symptoms are primarily apathy, social phobia, and lack of willpower/motivation.
>
> thanks a lot,
> anitaAnita - I'd almost forgot about left/right brain thing. I was at a schizophrenia conference a couple of years ago and Dr.Scott Purdon from Alberta Hospital - Edmonton showed some PET scans of Zyprexa and Risperdal in action (Risp lighting up the right side and Zyp lighting up the left side). I really don't know what Scott thinks of this today, but I see him in a couple of weeks and I'll ask him.
As for depression, the above presentation was done before we really new that the atypical antidepressants were mood stabilizers. Every depression is unique. I don't think you could really generalize (or maybe you can) where Zyprexa or Risperdal seems to enhance neurotransmission. I don't think that we have depression subtyped that well, yet. Maybe in the near future.
Lamictal is an anticonvulsant/mood stabilizer, not an antipsychotic. It seems to work very well for stabilizing bipolar depression.
I think that the 5HT-2A/D2 ratio of Zyprexa is greater than Risperdal, but as to in vivo binding affinities, I'm not sure. Anyways, I am starting to think that tweaking the receptor, rather than irreverisibly binding to it causes different second messenger responses. In other words, the atypical antipsychotics may not need to bind tightly to the receptor to result in a medicinal effect. So, looking at binding affinities of atypical antipsychotics may be misleading (then again, I can't prove this).
Personally I feel that Zyprexa is a better, overall mood stabilizer, but Risperdal may work better as an adjunct to SSRIs in OCD. For antidepressant augmentation, the gold standard is still lithium. It augments the action of many antidepressants. Seroquel seems to work best in a subgroup of people with bipolar disorder, but it seems to have a more calming effect, than an antidepressant effect.
As for diagnosing your depression; that I can't do. I can't tell an affective disorder from a personality disorder from a schizophreniform disorder. I just do the drugs. The docs have to tell me what the diagnosis is before I am of any help.
I hope this helps - Cam
poster:Cam W.
thread:46302
URL: http://www.dr-bob.org/babble/20001012/msgs/46304.html