No alcohol or drugs were found in captain remains. I believed (based on listening CVR and ATC radio) that captain was not so emotive or confused as it can look from this discussion.
In the report, as one of possible reason for loss of spatial orientation is mentioned the "direct" system of artificial horizon. In Russia, two types of attitude indicator are used. First of them is the same as AI in western planes and it was the type in this Tu-154B. The other type has different indication - in front of sky-ground cylinder a little plane symbol is placed. This plane banks left and right - of course in opposite direction than horizon line in "western" AI.
In the case of of very stress or panic situation something in your head can switch to old reflex you got many years ago.