[Neuroscience] Re: Depression, behavior, and Neurobiology

[Dr. Wayne Simon]

What effect does the growth of new hippocampal neurons have on depression? 
And how long does it take to show significant neuronal growth?  How nicely 
does this correlate with the decrease in depressive symptoms?  If 
bacteriacidal antibiotics kill infecting organisms, then why in some cases 
does it take weeks to get over an infection instead of relatively close to 
immediately?  Re-establishing neuro-hormonal levels closer to normal does 
not have to cause an immediate reversal of depression.   There are many 
reasons including post receptor effects, and other effects which can slow 
down a response.  Some neuronal responses, especially when they are 
combating complex neuronal imbalances, may take time.  Drugs like zyprexa 
can work on depression quicker than the drugs which are utilized solely for 
depression.  Some are starting the patients on anti-depressants, but 
combining them with atypical antipsychotics in low doses to try to get a 
quicker response to the depression.  And then discontinue the atypicals when 
the SSRI or or norepinephrine enhancer starts to exert its effect.  One can 
follow brain changes in humans non-invasively by following serial PET scans 
and or MRI's.  Computerized Electrophysiological brain mapping can also be 
helpful.