During infancy I also had very unusual problems (for a child) with social anxiety... Since getting ME, my depression seems to have cleared up, completely... this maybe just a coincidence, but it's very strange because I'd have thought the depression would have increased while I'm coping with a severe chronic illness... so i can't help wondering if maybe I've always had XMRV, since birth, and that it has caused me to have neurological problems all my life... And maybe when I went down with full-blown ME, the inflamation (or immune response) moved away from my brain into my body... maybe my body now responds to the virus in a different way.
I also no longer get full blown depressions, with ME its more like a series of much milder and shorter lasting low periods that occur randomly...almost as if a depression has been chopped into timy pieces and fed through my brain it little bits over the period of a few years.
Psychiatrists always said my clinical depression is caused by having a genetically-linked natural reduction in the appropriate level of neurotransmitters (serotonin/norepinephrine)in certain parts of my brain.
However, now having had ME for 12 yrs (since my mid 20s), i would hazzard an experienced guess that my depressions were more likely caused by temporary blockages to the blood supply in those certain parts of the brain, those blockages being formed by neuroimmune-activated inflammation. If i am found to be XMRV positive i would also expect to have had it from birth.