In 1983–84, as an undergraduate psychology student, I wrote a paper that stunned my seminar professor and left my classmates speechless. It proposed something no one in the room had heard before: that schizophrenia might be better understood through the filter of synesthesia — and, conversely, that studying synesthesia might illuminate the mysteries of schizophrenia. I wrote about this in a previous blog: How My Synesthesia–Schizophrenia Paper Anticipated Modern Research
At the time, both conditions were poorly understood. Schizophrenia research was dominated by dopamine models and behaviorist frameworks; synesthesia was still treated as a curiosity, something that existed more in the world of art than neuroscience. The two were rarely, if ever, mentioned in the same breath. My argument, presented in that seminar room, was that both conditions shared something deeper: atypical neural cross-activation, altered sensory integration, and the potential to reveal how the human brain constructs reality itself.
My professor told me afterward that psychologists spend their entire careers searching for a course of study, and that I had found one as an undergraduate. I didn’t realize until much later how true that was. For decades, my paper sat quietly — later made available online and now on Amazon as On Psychology: With an Illustration in Psychopathology via Synesthesia and Schizophrenia. And now, nearly forty years later, I’m seeing the very connections I outlined then begin to appear in neuroscience journals.
Also, on Academia.com.
Where Science Has Caught Up
1. Shared Genetic Susceptibility
In 2023, a Nature Translational Psychiatry twin and genome study found evidence of overlapping genetic and environmental factors between synesthesia and schizophrenia. The researchers stopped short of claiming causation but noted that both conditions may involve similar neurodevelopmental pathways. This echoes what I speculated decades ago — that these two seemingly opposite phenomena might stem from the same underlying architecture of perception.
2. Perceptual Gains and Losses
A 2021 study in Schizophrenia Bulletin compared synesthetes, schizophrenia patients, and neurotypical controls. The findings were striking: synesthetes showed enhanced top-down perception — strong, consistent sensory expectations — while individuals with schizophrenia displayed weakened top-down control and an overreliance on raw sensory input. One could think of synesthesia as perception enriched, and schizophrenia as perception unmoored. This dynamic, between structured and chaotic perceptual worlds, was exactly the kind of comparative insight I argued could advance our understanding of both.
3. Psychosis-Proneness and Cross-Modal Experience
In 2016, a Psychiatry Research study observed that people high in psychosis-proneness reported more synesthetic or pseudo-synesthetic experiences. These experiences were not pathological, but they blurred the line between creative and psychotic perception. This supports the idea that cross-modal sensory connections exist on a continuum — and that what we call pathology may, in some cases, be an intensified form of ordinary human variation.
4. Epidemiological Correlation
The Genetics of Synesthesia Project at the University of Edinburgh found an elevated rate of schizophrenia among people with grapheme-color synesthesia. While it’s not a causal link, it reinforces that these conditions may share predispositions — like overlapping circuitry or neurotransmitter sensitivity — rather than existing as unrelated anomalies.
5. Integrative Models of Perception
More recently, Neuroscience & Biobehavioral Reviews (2022) proposed a circular inference model suggesting that hallucinations and synesthesia might arise from similar predictive coding mechanisms — how the brain balances sensory input with expectation. In essence, when that balance tips too far in either direction, the world either becomes too tightly bound (synesthesia) or too unstable (schizophrenia).
What It Means (and Doesn’t)
These findings don’t mean synesthesia causes schizophrenia, or that one leads to the other. That was never my contention. Rather, they support the notion that both emerge from the same underlying human machinery — perceptual integration, neural connectivity, and the brain’s delicate dance between sensation and interpretation. One condition stabilizes meaning where there might be none; the other unravels meaning where there should be structure. Studying both together allows us to see the architecture of consciousness from two opposing angles.
When I first wrote about this, I described the two as mirrors — each reflecting an extreme of perceptual experience. Modern neuroscience, in its own language, is now describing that same mirror: a shared substrate, expressed through different outcomes of connectivity and control.
Why It Matters
Understanding these parallels could reshape how we view not just mental illness, but creativity and perception itself. The continuum from ordinary imagination to artistic synesthesia to pathological hallucination may not be a divide at all, but a spectrum of how the brain constructs reality. This perspective challenges the way we draw lines between health and disorder, or between creative brilliance and madness.
For psychology, it’s an invitation to reexamine how perception becomes meaning. For neuroscience, it’s a map of how small shifts in feedback loops can tip the mind between clarity and chaos. And for me — it’s a kind of closure.
That stunned silence in my senior seminar on abnormal psychology in 1984 has finally found its echo in today’s research journals. I just wish I could have gotten it out there decades sooner.
References
-
Powers, A.R. et al. (2021). Perceptual gains and losses in synesthesia and schizophrenia. Schizophrenia Bulletin, 47(3):722–731.
-
Banissy, M.J. et al. (2023). Genetic and environmental contributions to the link between synesthesia and psychiatric traits. Translational Psychiatry 13(1).
-
van Leeuwen, T.M. et al. (2016). Synesthetic experiences and psychosis proneness: shared perceptual styles. Psychiatry Research, 238:293–300.
-
University of Edinburgh, Genetics of Synesthesia Project (2020). Schizophrenia and Synaesthesia.
-
Bouvet, L. et al. (2022). From hallucinations to synaesthesia: a circular inference model of perception. Neuroscience & Biobehavioral Reviews, 139:104735.
Murdock, J.Z. (1984). On Psychology: With an Illustration in Psychopathology via Synesthesia and Schizophrenia; with Some Notes on Field Theory, Albert’s Mind, and the Status Quo: The Necessity of Contextualism in Psychology. LgN Productions (reissued together in 2012, also on Academia.com).
Cheers! Sláinte! Na zdravie!
Compiled with aid of ChatGPT
No comments:
Post a Comment