The rapid growth of the mental epidemic of psychosomatic disorders in the modern world with constituting from 20 to 60 % of medical conditions warrants further search for new approaches to etiopathogenesis, its course, treatment and prevention. A new synergetic biopsychosocial spiritual methodology of mental medicine (MM) can significantly expand the multidisciplinary capabilities of prenosological screening and forecasting, individualization of routes and assistance programs. The concept of mental immunity (MI) as a matrix of identity and interface of consciousness is grounded. For a generalized characteristic of the continuum of qualitative mental states modulated by MI functions, the term "menom" is proposed. «Epimenom» accumulates acquired peculiarities of MI. Functional pleiotropy of MI is described. Systematic disorders of MI functions as a "mental code" of consciousness and identity, which make up the clinical phenomenology of nonspecific mental immunodeficiency syndrome (SMID) in psychosomatic diathesis, are systematized. The priority task of primary prevention of diathesis is to increase the resources of MI and the registers of mental resilience of the psychosomatogenic family. An emergent rule of the "four keys" of sanogenetic therapy is proposed.