The randomized controlled trial occupies an ambivalent position within the Seba depth-psychology corpus. On one side stand empirically oriented researchers—Chambless and Hollon, Miller and Wilbourne, McPheeters, and the systematic-review tradition broadly—who treat the RCT as the methodological gold standard for establishing treatment efficacy, the necessary foundation upon which any claim to ‘empirically supported therapy’ must rest. On the other side, voices such as Roesler and de Maat document the uncomfortable fact that depth-psychological modalities—Jungian and psychoanalytic therapies preeminently—have generated naturalistic outcome evidence rather than RCT evidence, raising the question whether the RCT’s requirements of randomization, blinding, and homogeneous samples systematically disadvantage relational and long-form treatments. Chambless and Hollon acknowledge this tension directly, noting that RCT participants, though selected for homogeneity, are not necessarily less complex than clinical populations, and that efficacy findings require extension into effectiveness and cost-utility research before their generalizability is assured. Miller’s Mesa Grande project sharpens the epistemological stakes: methodological quality of clinical trials, not mere RCT designation, determines inferential strength. Taken together, the corpus treats the RCT not as a transparent window onto therapeutic truth but as a contested instrument whose authority depends on design logic, allegiance effects, attrition management, and the degree to which standardized conditions can capture the interpersonal reality of psychotherapy.