Introduction and context
A recurring thread in the literature is that psychiatry and psychotherapy have periodically borrowed the conceptual vocabulary of contemporary physics as a way to re-think clinical phenomena and theory construction, including a shift from earlier Newtonian metaphors toward explicitly “quantum” ones in deep psychotherapy and borderline presentations.[1, 2] One explicit statement of this shift argues that Newtonian principles (and by analogy Freud’s Newtonian constructs) can be useful “to a certain depth of therapy,” but that “beyond that point” the “appropriate metaphors are those of quantum physics.”[1, 2] In that framing, quantum metaphors are used to explore “duality, free will and patient-therapist interaction,” placing clinical agency and the therapeutic dyad near the center of the analogy rather than peripheral to it.[1, 2]
The historical lineage of “quantum–psyche” cross-fertilization is also represented (in a more biographical/intellectual-history register) by accounts of Carl Jung and Wolfgang Pauli “bounc[ing] ideas off each other,” which has served as a reference point for later work seeking conceptual bridges between quantum theory and psychiatry/psychology.[3] The same broad cultural moment is sometimes narrated as coeval with foundational developments in both psychiatry and quantum physics, for example noting that in 1913 (the year associated with Jaspers’ early psychiatric work) Niels Bohr published a quantum theory of the hydrogen atom and raised the unsettling possibility that there may not be “a single objective accepted reality,” but that it “came into being by observation.”[4]
Across sources, it is important to distinguish (i) metaphorical/methodological uses of quantum ideas to articulate epistemic limits and relational features of clinical work from (ii) literal mechanistic claims that the brain implements quantum processes responsible for psychiatric symptoms or consciousness.[5–7] Several authors explicitly emphasize the metaphorical intent, warning that the “confluence does not assert a literal alignment of cerebral functioning” with quantum mechanics, and instead positions quantum principles as “metaphorical tools” for complex psychological phenomena.[5]
Observer effect and uncertainty
A central methodological parallel is the rejection of a fully neutral observer in both quantum measurement and psychoanalytic/psychotherapeutic practice, with multiple sources explicitly drawing analogies between quantum observation and the therapist’s participation in a bidirectional clinical process.[8] In one influential psychoanalytic framing, psychoanalysis is described as evolving from “a traditional unidirectional model in which the therapist is an objective observer” to a “bidirectional model” emphasizing interaction, explicitly stating that “the notion that the therapist can be a neutral observer” is “abandoned.”[8] The same text explicitly links this to the Copenhagen-era “abandonment of the notion of the neutral experimenter/observer,” and claims that the experimenter’s consciousness exerts a “critical metaphysical influence” on quantum experimental outcomes in the subatomic realm.[8]
Within relational/psychoanalytic discussions, Heisenberg’s uncertainty principle is often invoked less as a literal physical constraint and more as a template for thinking about subjectivity and measurement-ladenness: one source explicitly quotes that “the position of the observer and the acts of observation influence the nature of the data gathered,” and concludes that “perceptions are neither objective nor absolute” but “shift with the unique point of view of the observer, or of the analyst in relation to the patient.”[9] The same line of argument highlights that in physics “we must isolate, and by definition alter, a wave or particle in order to study it,” using this as a methodological analogue for how clinical inquiry or interpretation can alter what becomes available for observation in the analytic situation.[9]
A closely related strand focuses on self-observation as a psychiatric/psychotherapeutic epistemic problem: one text states that it is “impossible” to make “objective” observations of one’s own thoughts and feelings because the observer uses those same thoughts and feelings to make observations, while psychiatric theory often assumes a “clear separation” between the observing part and the observed part of the self.[10] In that account, “analogies from quantum physics” are proposed as a way to “elucidate this paradox,” and understanding these complexities is linked to understanding “many of the enigmas of psychotherapy.”[10]
In psychology research methodology, the “observer effect” is also framed as a general scientific challenge in measurement: one paper defines the observer effect as “the impact that observing has upon a result,” distinguishes external and internal forms of observation, and argues that not considering observer effects can introduce “biases and distortions” compromising validity and reliability.[11] The same work proposes mindfulness as a “platform to account for, explore, and intentionally harness” the observer effect and as a style of reflection that aims to “dismantle” observer effects by attending to present-moment experience without judgment or elaboration.[11]
Complementarity
Complementarity is repeatedly used as a bridge concept for psychiatry because it offers a structured way to treat apparently irreconcilable descriptions as mutually necessary, rather than forcing them into a single, unified perspective.[12, 13] A psychiatric-psychotherapeutic application explicitly proposes that “medical psychiatric” and “psychotherapeutic” approaches each have their own internal logic that is “independent from and simultaneously complementary” to the other, explicitly invoking Bohr’s principle for systematizing “irreconcilable data obtained by observers with differing perspectives.”[13] In a related methodological move, the same approach proposes that each patient “should be examined simultaneously and independently” from these two “systems of coordinates,” emphasizing parallel perspectives rather than reduction to one viewpoint.[13]
In mind–body and biopsychosocial discussions, complementarity is also used to articulate why full, simultaneous description may be impossible: one text states that “a complete simultaneous description” of biochemical and psychological brain processes is “impossible,” and that the more precisely biochemical processes are identified, “the more is lost” in understanding “the essence of the mind.”[14] Another complementarity-based model defines complementarity as requiring “two incompatible descriptions” to describe something “in full,” and states that “the physical and the mental side of the human organism are two complementary notions,” explicitly tying this to complementarity as a defining property of quantum systems.[12]
Several sources explicitly separate complementarity from the Copenhagen interpretation while maintaining the value of complementarity for plural explanatory “grounds” in psychology: one proposes Physikos, Bios, Socius, and Logos as “complementary grounds for theoretical explanation,” and advises staying within one ground at a time while shifting to a complementary ground for the same target “without being inconsistent.”[15] The same source argues that psychology “cannot have a Copenhagen Interpretation per se” due to lack of comparable clear experimental data, thereby positioning complementarity primarily as a philosophical/theoretical pluralism tool rather than a direct import of physics’ measurement disturbance story.[15]
Complementarity is also extended into consciousness research as a way to reframe oppositions (analysis/synthesis, logic/intuition, doing/being) into “more generous conjugation,” with some authors explicitly adding that the physical principle of uncertainty acquires metaphoric relevance by limiting the “attainable sharpness of specification” of such complements.[16]
Superposition and collapse
Superposition and collapse serve as particularly generative metaphors for psychiatric indeterminacy, ambivalence, and the transition from pre-articulated experience to articulated report, and some sources also advance literal neurobiological hypotheses (e.g., microtubular states) alongside metaphorical uses.[6, 17] A metaphor-driven psychological account explicitly represents “the unconscious” as “a superposition of mental states,” and describes consciousness as “decoherence of unconscious experiences,” using wave-function “collapse” as the physical analogue for the unconscious-to-conscious transition at the “psychic level of being.”[6]
Other texts translate superposition more directly into clinical phenomenology, for example proposing that explanatory and psychotherapeutic opportunities may emerge from “superpositional logic” and malattunement in the “primary process thinking of schizophrenia,” including an explicitly Many-Worlds-inspired image (“Everett’s quantum ontology in the ‘alternate worlds’ of psychotic perception”).[18] In a more explicitly formal/measurement-analogy approach, one model claims that asking a person what they are thinking “right now” results in “introspection and in the collapse of a superposition of states into a single thought,” emphasizing collapse as a consequence of inquiry and report rather than as a purely internal mechanism.[19]
In cognitive modeling literatures that explicitly adopt quantum-like mathematics, superposition is treated as a way to represent “states of very deep uncertainty” that “can not be modeled by classical probability distributions,” supporting the claim that quantum formalisms can represent cognitive indeterminacy beyond classical probabilistic mixture models.[20] In quantum predictive brain formulations, superposition is explicitly defined as an “indefinite state” prior to collapse and is interpreted as expressing “conflict and ambiguity between potential observable states,” with collapse described as a “transition from a superposition state to a definite state.”[21]
Entanglement and the therapeutic relationship
Non-locality and entanglement are invoked in several distinct ways across this literature: as metaphor for relational/interpersonal dynamics, as generalized “quantum-like” systems concepts, and (in some cases) as claims about psychophysical or mind–body nonlocal correlations subject to experimental test.[22–24] A systems-theoretic extension (Generalized Quantum Theory) predicts “nonlocal, generalized entanglement correlations” outside proper quantum systems and expects such correlations when global observables are “incompatible or complementary” to subsystem observables, which is then presented as applicable to psychology and biology.[23]
At the level of psychotherapeutic relationship, some accounts describe interactions between therapist and patient as involving bidirectional influence that can be conceptualized via entanglement-like coupling: one explicitly defines transfer and countertransference as a two-way “interaction between the therapist’s unconscious and the patient’s” and acknowledges the “possible influence not only of the therapist on the patient, but also of the patient on the therapist.”[19] A separate paper proposes that “intuitive response” is a cornerstone of patient–therapist interactions and introduces a “Nonlocal Neurodynamics model” that complements classical communication with “nonlocal-participatory informational channels” arising from the quantum/classical nature of the body/brain/mind system, explicitly linking clinical phenomena such as “thought transference” and “synchronicity” to this model.[25]
Some sources go further by proposing methodological tools to test psychophysical “action at a distance”: one paper treats entanglement as a violation of “local realism” in a psychophysical context and proposes extending an Information Theoretic Bell Inequality algorithm to medicine and psychological science to estimate whether “action at a distance” may be real in the phenomenon under investigation.[24] In a contrasting epistemic stance, a QBism-oriented critique argues that conventional quantum theory’s ontic non-locality and entanglement have been used as metaphors for therapeutic process (including “Patient-Practitioner-Remedy entanglement”), but that in QBism non-locality and entanglement are an agent’s “subjective degrees of belief,” challenging earlier ontic metaphor deployments by reframing them as epistemic.[22]
Epistemology and method
Multiple sources argue that psychiatry often relies (implicitly or explicitly) on classical physics’ assumptions of observer-independent objectivity, while quantum-informed metaphors foreground observer participation, context dependence, and the limits of single-description realism.[26, 27] One empirical/methodological study explicitly states that although quantum mechanical principles replaced Newtonian ones in physics, psychiatry continues to apply Newtonian principles “in models of the mind and its diseases,” and it frames quantum ideas as potentially more consistent with clinicians’ experience of observer roles and interpersonal relationships.[26]
Empirically, that same line of inquiry reports that psychiatrists were given clinical scenarios corresponding to quantum versus classical physical principles, and that respondents were significantly more likely to rate the “quantum principles” scenarios as consistent with their experience, with reported for the difference.[26] The existence of such findings is frequently interpreted as supporting the plausibility (at minimum) of quantum-derived metaphors for clinical phenomena involving observer involvement and relational complexity, rather than demonstrating any literal quantum mechanism in neural tissue.[26]
Epistemological critiques also arise within psychiatry’s broader philosophy-of-science debates: one paper argues that biopsychosocial psychiatry (when grounded in analogies between neural network theory and classical statistical mechanics) is plagued by “tensions and inconsistencies” about “causation, physical scale, and objectivity,” and advances a post-classical paradigm grounded in quantum principles as a potential source of improved “explanatory adequacy” and “theoretical coherence.”[28] Another commentary suggests that psychiatry’s tension between dogmatism and eclecticism may have “no solution” beyond a “method-based psychiatry” using different methods for different purposes, while also raising the possibility of an integrated theory of brain and mind “based on quantum mechanical concepts” to address the translation from parallel neural processing to sequential mental experience.[29]
Several sources frame these issues not merely as clinical rhetoric but as a general problem of model-building under complexity: one explicitly states that “the observer thus becomes a builder of models, a manager of complexity,” giving treatment the character of a “truly empathic relationship,” and contrasts reductionist “edifice” metaphors with complexity-theoretic “network” metaphors emphasizing relationships and dynamic openness.[18]
Quantum cognition and formal models
A distinct (and comparatively more technically disciplined) tradition uses quantum probability, quantum logic, and related formalisms to model cognitive and behavioral data that violate classical probability and logic, and these approaches are sometimes positioned as directly relevant to psychiatric assessment and computational psychiatry.[20, 30] In this tradition, one motivation is that “the laws of classical logic and probability are routinely violated” by cognitive phenomena, and that cognitive data can exhibit a “probabilistic interference effect,” motivating the application of quantum mathematical apparatus to cognition and decision-making.[20]
A key construct is complementarity in judgment and question answering: one account defines complementarity in terms of mutually exclusive measurement conditions where “the sequence or order of the measurements matters,” and it applies this to psychological question order effects (e.g., judgments of honesty) where one cannot measure both answers simultaneously and where order affects responses.[31] In that same account, incompatibility implies an uncertainty-like trade-off (certainty about one answer implies uncertainty about the other) and a superposition-like limitation (one cannot be certain about both simultaneously), explicitly mapping these to the “uncertainty principle” and “superposition principle” of quantum theory.[31]
A related modeling framework, Quantum Predictive Brain, states that “top-down predictions and bottom-up evidence are complementary,” such that determining one state requires accepting “non-reducible uncertainty” about the other, and it links this complementarity to non-commutativity of quantum measurements.[21] Methodologically, it claims a Bayesian framework is inadequate for “incommensurable points of view,” and instead uses projective measurement and collapse language to model state updates under unconventional surprises and contemplative experience.[21]
Finally, explicitly psychiatric applications are proposed via quantum decision theory and quantum probability: one paper argues for the “importance of employing quantum decision theory in psychiatry” and gives an example application to autism research, while other work frames quantum probability as useful for modeling behavior given the prevalence of uncertainty in human interaction with the world and highlights order effects as a key application domain.[30, 32]
Critiques and caveats
A repeated caveat is that quantum terminology may remain metaphorical unless a substantive mathematical or empirical bridge is built: one analysis concludes that parallels between quantum mechanics and psychology “look insufficiently substantiated,” stating that quantum-physical terminology in understanding mental experience “does not rise to the level of scientific theory, remaining a metaphor,” while still asserting that “quantum psychology has a predictive potential.”[6] Another source similarly distinguishes between the value of models “as metaphors” and the “intractable problems” that arise when metaphors are taken as literal “explanations of reality.”[33]
A further critique concerns evidential standards for quantum-mechanistic claims in psychiatry and consciousness research: one neuropsychiatry-oriented text states that quantum theories of mind/brain/consciousness are “simply models, theories, and assumptions,” and emphasizes that there are “no convincing experiments supporting their claims,” even as it characterizes mainstream neuropsychiatric paradigms as incompletely adequate.[34] Some clinically oriented approaches also explicitly label their scientific basis as speculative while appealing to quantum-theory-of-consciousness and remote viewing/mediumship literatures as potential supporting evidence, underscoring the risk of conceptual drift from disciplined modeling into highly speculative domains.[35]
At the same time, several authors explicitly attempt to prevent “quantum mysticism” by stressing that the value of quantum principles may be metaphorical and heuristic: one paper emphasizes that quantum principles can serve as “metaphorical tools for apprehending intricate psychological phenomena” and explicitly states that this does not imply a “literal alignment of cerebral functioning” with quantum mechanics, while also noting that psychological variables are diverse and interconnected in ways that make quantification challenging compared to physics.[5]
Common aspects
Across the heterogeneous literature, several cross-cutting common aspects emerge as relatively robust (even when authors disagree about literal mechanisms).[5, 28] The table below summarizes a small set of recurring “quantum-inspired” motifs and the kinds of psychiatric/psychological targets they are used to illuminate.
- First, the participant-observer epistemology appears in both psychoanalytic theory (abandoning neutrality) and quantum measurement narratives that explicitly reject a neutral experimenter/observer, creating a shared emphasis on the necessity of including the investigator/clinician in the description of what is observed.[8, 37]
- Second, complementarity functions as a structured pluralism: the need for multiple, incompatible-but-necessary perspectives is used to frame mind–body, biochemical–psychological, and medical–psychotherapeutic dual-aspect approaches as jointly required but not simultaneously realizable in a single description.[12, 14]
- Third, indeterminacy and superposition provide a formal and metaphorical language for deep uncertainty in cognition and for psychiatric experiences where articulation or questioning appears to crystallize one trajectory among multiple possibilities.[19–21]
- Fourth, context dependence and order effects—formalized through non-commutativity and interference in quantum cognition—offer a way to model why the order of questions, observations, or interventions can change the observed psychological response, a phenomenon directly relevant to assessment and therapy process.[20, 21, 31]
- Fifth, holism and “wholeness” recur as a motivating parallel: quantum theory’s emphasis on wholeness is proposed as relevant to psychopathology where “breakdown of unity in the mental domain” is a key feature, and this motivates attempts to bridge subjective mental properties and physical brain processes via information-theoretic or ontological (e.g., Bohmian) constructs.[38, 39]
10. Conclusion
Taken together, the reviewed sources support a picture in which quantum physics functions in psychiatry primarily as a repertoire of epistemological and methodological metaphors—observer participation, complementarity, indeterminacy, context-dependence, and holistic coupling—used to articulate limits of objectivity and the need for plural descriptions in clinical science.[6, 8, 13, 31] The literature also suggests that when quantum ideas are used as disciplined formal tools (quantum probability, complementarity-based models, quantum decision theory), they can generate testable models of cognition and judgment under uncertainty that may be relevant to psychiatric assessment and computational psychiatry, especially for order effects and interference-like phenomena in responses.[30–32]
At the same time, multiple authors explicitly warn that quantum terminology in psychology can remain “a metaphor” without a mature mathematical model of the psyche and that speculative extensions can outpace evidence, underscoring the importance of separating heuristic value from claims of literal quantum mechanisms in the brain.[6, 34] A balanced reading of this literature therefore treats quantum-inspired approaches as most productive when they (i) clarify epistemic limits and clinician–patient interaction in practice and (ii) provide formal probabilistic tools for modeling cognitive and decision phenomena that resist classical accounts, while treating mechanistic claims and nonlocal clinical interpretations as hypotheses requiring proportionate empirical support.[5, 6, 24]
