Mental ill health is now recognised as the largest cause of short and long term disability worldwide costing the global economy US$2.5T (€798 billion in Europe), with a projected increase to over US$6T by 2030. Approximately 1 in 5 of us (more than 450 million people) experience mental health problems during our lifetime with about 5% suffering from a serious mental illness such as schizophrenia, bipolar, and major depressive disorders. Illness specific treatments are available that allow patients to resume normal functioning in society but physicians are struggling to make accurate diagnosis, match therapy to condition, and provide timely care, affecting more than 50% of patients who don’t receive adequate care.
The current gold standard is based on interviewing patients over several months or years to document their behaviour and symptoms with misdiagnosis occurring 50% of the time. When patients’ history, symptoms and behaviour don’t meet the criteria set out in the diagnostic manual, it may take up to 10 years to diagnose the illness. Symptom based clinical evaluation requires significant amount of time, expertise, hence cost. There also remains the uncertainty as to whether an illness can in any event be diagnosed without the full diagnostic criteria being met. Delays in receiving a diagnosis can significantly impede delivery of the most effective treatment plan, exposing the patient to risk of further deterioration in well-being, reduction in quality of life leading to job loss, family breakdown, and self-harming.
The development of simple objective tests for the major psychiatric disorders that are stable, sensitive and specific enough to be of clinico-diagnostic and treatment value would be of enormous benefit. Decades of effort have been spent attempting without success to identify assays that could be used as diagnostic markers in psychiatry. Attempts to find radiological and serological assays have proved especially frustrating. Although abnormalities of eye movements were first observed in unmedicated psychotic patients over 100 years ago, they have never been considered sensitive or specific enough to be of diagnostic value at the level of the individual patient, and as a result, the observations have been generally ignored and neglected. Modern eye tracking devices and sophisticated analytical techniques have reinvigorated interest in the potential of eye movements to assist psychiatrists and healthcare professionals. We are the first to discover that different eye-movement tests give substantially more information about underlying neural pathways and realised that a combination of performance measures and tests would be key to developing a psychiatric biomarker with the required sensitivity and specificity. This has led to the development of the patent protected SaccScan eye test which has been demonstrated to detect schizophrenia with better than 95% accuracy and is being extended with the same precision to bipolar disorder and major depression illnesses. The test can be performed within 30 minutes with simple desktop equipment and results produced over the internet.
