Across the depth-psychology corpus, ‘tendency’ functions as a foundational explanatory concept, naming the directional, vectorial quality of psychic and somatic forces before those forces resolve into discrete acts or symptoms. The term carries markedly different theoretical freight depending on the author. Jung employs it structurally, speaking of the psyche’s tendency to split into autonomous complexes and of tendencies toward change conditioned by internal and external influences, thereby grounding psychopathology in a general property of psychic organization. Freud uses ‘interfering tendency’ in the precise sense of a latent intention that disrupts conscious speech, situating tendency within his economic model of competing psychic pressures. Janet, as refracted through van der Hart and colleagues, systematizes the concept most elaborately, constructing a hierarchy of action tendencies ordered by mental efficiency — from reflexive fixed action tendencies through the highest progressive tendencies requiring full personality integration. Rank extends the term into metapsychology, reading the dream’s wish-fulfilling ‘reversal tendency’ as the unconscious’s sole available language for forward movement. Neumann, operating in the register of archetypal psychology, traces how the destructive tendency of the Great Mother becomes assimilated as an ego tendency through the adolescent’s self-confrontation. Collectively, these positions reveal a field-wide commitment to tendencies as irreducible psychodynamic vectors whose developmental fate — integration, fixation, or regression — largely determines psychological health.