I don't think it is a good idea to employ 'psychological' or even 'psychosocial' explanations for nationalism, religion, etc. Psychoanalysis doesn't explain history; history explains psychoanalysis (both its rise and possible fall). As Joel Pfister aruged, I think that '"the psychological" makes sense as part of a larger cultural project to reinvigorate discourses of "the individual".' Or take a look at Ian Watt, and compare _Moll Flanders_ (1722) and _Clarissa_ (1747-48), and see how much 'psychological depth' that the latter already gained (at the expense of the scope of actions that Clarissa is allowed, I may add). _Clarissa_ dazzled Dr. Johnson as well as Rousseau by its 'knowledge' of 'the human heart.'
To paraphrase Pfister, Freud doesn't, for instance, 'explain' psychological novels (and other modern cultural and social artifacts); the latter contributed to the making of Freud.
Yoshie