Pump Head after Open Heart Surgury vs. Pump Head with the LVAD

A little background.  I am an Engineer by profession & trade.  And when I run into a problem like what I am working on now I like to find out the what's, and why's. I have been wondering why, so many LVADs are depressed or have had a major change in their personality.  I had asked my MCMS Team about this and they suggested looking at what happens to many patients who have had Open Heart Surgery where they were on a Heart Lung Machine. It appears on the face of it from what I have found is that thousands of men & women come away from a successful OHS; that while after being on the HLM they tend to be depressed, angry, full of anxiety and in a number of cases a complete change in personality.   In the past 3 months I have read over a thousand pages of blog posts from people who have and are going through this.  The Doctors tend to tie all of these folks  into a Syndrome they are calling "Pump Head", with no real explanation as to why or is it curable or what the real cause is.  In some cases the patient comes out of it and other times they don't and either completely change their lives or make everyone's life a living hell for those who are around them. So...the only correlation I can find between them and us is that we all do at some point develop "Pump Head",  with the difference being that we are still on the HLM although a bit smaller.  I have met a number of LVADs both XT & DT at my Center here in San Diego, and many of them typically the  65+ patients exhibit the same issues as those with only the OHS.  Deep dark depression, sudden changes in personality, finality of  "why bother", just a complete lack of caring that they are alive and appear not only depressed but become withdrawn as time progresses. As to me yup, I have had really bad bouts of depression, and what I have found in my own personality are that little emotional things that I would pass off before my LVAD, now have me in tears and crying jags.  And when I hit these points I really feel like I am losing it.  But then I snap back.  Don't know why.  And I decided some time ago not to take mind benders to help with this.  What I am looking for is anyone or all of us who have or are going through this.  And their stories.  And I also have a Hypothesis.  The HLM and the LVAD change the rhythm of our bodies at the most basic level.   The HLM and the LVAD pump or move the blood through our body.  However we have no pulse, and no real heart beat.  Exactly what a patient on an HLM experiences.  It is this lack of rhythm that is affecting us?  If we were to replace the heart beat we normally feel and experience each night while we sleep, would this help?  I don't know but I have purchased a Heart Sound pillow like the one we used for my children when they were newborns so lets see if it helps at all. Thoughts ????