Background of the Yale University PRIME Screening Test

The PRIME screening test was developed by Drs. Tom McGlashan, Tandy Miller, Scott Woods and the PRIME group in the psychiatry department at the Yale University Medical School. We are greatly indebted for their support in allowing us to use this test and provide it to the public. More information on the test is provided after you complete it.

The PRIME screening test was developed based on a structured interview known as the SIPS (Structured Interview for Prodromal Syndromes), an in-depth patient interview. If you are a doctor, you may want to review more scientific information on the SIPs interview below. Please also note that the same in-depth information provided below is included with the summary of the results at the completion of the screen.

Screening tests can be very helpful for many illnesses, but their limitations must be understood. There is no such thing as a perfect screener. Some people who actually have the illness are going to screen negative – this is called a “false negative” screen. Some people who do not have the illness are going to screen positive – this is called a “false positive” screen. A useful screener has low rates of false negative and false positive results, but again no screener is perfect.

Researchers at Yale University’s PRIME Clinic developed the PRIME screener, as well as the SIPS structured interview to help identify symptoms of the schizophrenia prodrome before the patient become fully psychotic. These symptoms are resemble those of schizophrenia but are milder.

For example, a milder experience of hallucinations might be termed “perceptual abnormalities.” Prodromal patients with perceptual abnormalities might for example hear noises or sounds that are not really there but not actual voices. A milder experience of delusions might be termed “unusual thought content.” Prodromal patients with unusual thought content might for example wonder if it is possible to influence someone’s mind but not believe that their thoughts were under the control of someone else.

In a small sample, about 50% of patients who met criteria for a prodromal syndrome after having a SIPS developed a schizophrenic psychosis in the next year. None of the patients who had a SIPS but did not meet prodromal criteria developed psychosis. These data suggest that the SIPS interview has substantial “predictive validity.”

As of 2002 the SIPS interview had been given to 38 people at Yale’s PRIME Clinic. Of these 38, 22 were diagnosed either as prodromal or as a new-onset case of schizophrenia according to a structured interview called the SIPS (Structured Interview for Prodromal Syndromes) and 16 were neither prodromal nor psychotic. The SIPS interview was positive in 76% of the people who were prodromal or psychotic and negative in 24% (24% false negative). The SIPS interview was negative in 100% of the people who were neither prodromal nor psychotic (zero% false positives).

No one knows yet how the PRIME Screen will perform in this internet setting. Even though the false positive rate was zero in the patients at the PRIME Clinic who helped to refine the screen, the false positive rate could be very high among people who visit and take the PRIME screening test here. Thus we are not certain how many people who are not prodromal or psychotic could get positive screens. If these false positive screens were to happen a lot, a positive screen might not be very useful.

A screen result is not the same thing as a diagnosis. People who have a positive screen should consider going for a diagnostic evaluation by psychiatry professionals if they are concerned.

Remember that having a positive screen does not necessarily mean that you are in the early phases of schizophrenia or psychosis (the "prodrome"). Although the people who screened "positive" during the development of the PRIME screen were all ill, many of the people who screen positive on could turn out not to be ill. If you are worried about yourself you should have a diagnostic visit with a qualified psychiatrist or psychologist.

The PRIME Screening test is not considered final, and may be revised based on future research.

Initial data on progression to schizophrenia and on prodromal diagnostic agreement that has been published on the structured interview (SIPS) include:

More information on screening tests and how they are being used in research is provided in the articles below:



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