The practice of mental illness diagnosis has long been less than scientific, as few biological markers have been identified for any of the mental illnesses. This month, a study published in the academic journal Biological Psychiatry states that a simple eye movement test can detect schizophrenia, and with an astonishing 98% accuracy.
The eye tests include having a person track a slow-moving object, hold their gaze on a fixed object, and look at common scenes—‘free viewing.’ In the first test, people with schizophrenia demonstrate a deficit in that their eye movements fall behind in tracking the object, and then catch up with a sudden eye movement. People without schizophrenia are able to track smoothly, in comparison. For the fixed-object test, people with schizophrenia have a less steady gaze than people without, and on the final test, free viewing, those with the illness display atypical scanning patterns compared to data for ‘normal eye movement.’
I found it interesting that there was no difference in test results for people with schizophrenia who were on medication versus those who were medication free.
The authors of this study are recommending that the eye tests be used as a supplement to the existing symptom-based diagnoses method. In addition to providing a biological marker for the diagnosis of schizophrenia, the tests are quick, inexpensive and can be administered by a medical assistant or a first-line physician (general practitioner).
It also struck me that these tests could be effective for those people who have paranoia as a primary symptom and therefore don’t respond well when asked a bunch of personal questions (as a diagnostic approach). Back in 2000, my mum was in the hospital for a minor surgery and so her doctor arranged for a psychiatric team to visit her. When they started asking questions, she became suspicious and irritated and pulled the bed sheet up over her head. With eye tests, a clinician could potentially gather information without having the subject feel like they’re being interrogated and clam up.
Here’s a link to the entire journal article: Simple Viewing Tests Can Detect Eye Movement Abnormalities That Distinguish Schizophrenia Cases from Controls with Exceptional Accuracy.
Are you aware of any other tests that provide biological markers for mental illnesses? Please share your information on this fascinating topic!