Perceptual Disturbances Not a Major Predictor of Schizophrenia Onset

A new study has found that perceptual disturbances — a milder form of full-blown hallucinations — are not necessarily predictive symptoms of schizophrenia. Perceptual disturbances may involve seeing shadows or hearing knocking noises with a sense that these experiences are “not real.”

Although some people with perceptual disturbances do go on to develop full-blown psychosis, there are just as many people with these symptoms who do not, according to the researchers.

Instead, they found that suspiciousness and unusual thought content are most likely to signal the onset of the disease. This risk is further enhanced if the person shows difficulty with focus or concentration.


I’m wondering what exactly perceptual disturbances are and what separates them from hallucinations… Most professionals that I’ve talked with about this do not differentiate between them, but some do. It’s confusing.

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Quote: “A tendency to extract spurious, message-like meaning from meaningless noise was assessed as a risk factor leading to shizophrenia-spectrum disorders by assessing word length of speech illusions elicited by multispeaker babble in 43 people with prodromal symptoms…” Source: Extracting spurious messages from noise and risk of schizophrenia-spectrum disorders in a prodromal population written in British journal of psychiatry (2007), 191, 355-356 by Ralph E. Hoffman and his colleagues

Quote: “Recently, it has been proposed that exaggerated top-down processing may generate spontaneous perceptual output, and that this may constitute a cognitive predisposition toward hallucinations… …We conclude that aberrant top-down processing, particularly in the form of strong semantic expectations, may contribute to the experience of auditory-verbal hallucinations.” (My remarks: To expect to access a verbal message in response to a slightly distorted maybe distant voice can be assumed to motivate a highly context dependent behaviour which makes it possible to restore and better distinguish a verbal message and to frequently be forced to restore a verbal message may generate a tendency to expect to hear a verbal message in response to what people normally ignore…) Source: Schizophrenia Bulletin (2010) 36 (1): 151-156. Semantic Expectations Can Induce False Perceptions in Hallucination-Prone Individuals by Ans Vercammen and André Aleman

I have perceptual disturbances. I’m fairly certain it’s a symptom of derealization.

Spatial distortions where everything is always shifting and moving slightly, lagged images are very common, something like a visual echo, it happens constantly when i’m watching tv and the scene changes, then it looks like there are two things being played at once for about half a second

Detail is harder to see in most things, my vision will unfocus frequently, which looks not unlike the autofocus on a phone camera (if it worked in reverse haha)

Kinda like being on a really low dose of acid without the colors.

I do have other symptoms that are more cause for concern, but a majority of my symptoms fit the perceptual disturbance category so far. Nothing auditory though.