rEVealIng Drug Effects when applyiNg psychomeTrics In schizophreniA triaLs (EVIDENTIAL)

Mental health conditions affect many people across Europe, with an estimated one in six individuals experiencing a mental health problem in any given year. Schizophrenia is one of the most serious of these conditions. Schizophrenia is a chronic, severe mental health condition that affects how a person thinks, feels, and acts, often causing them to lose touch with reality (psychosis). It affects about one in 300 people and can greatly disrupt daily life. Many individuals with schizophrenia struggle with symptoms such as hallucinations, delusions, lack of motivation, and difficulties with thinking and communication. People living with schizophrenia often face high unemployment rates and shorter life expectancy compared with the general population.

Although antipsychotic medications are the main treatment for schizophrenia, they do not work well for everyone. Antipsychotic medications work by altering brain chemistry to help reduce psychotic symptoms like hallucinations, delusions and disordered thinking. Around 20–30% of people do not experience enough improvement with currently available treatments. There are also important differences in how people respond to treatment based on factors such as sex or social experiences, and they may experience stigma or discrimination. Because of this, improving how we measure treatment effects in clinical trials is important for developing better care.

In most schizophrenia clinical trials, researchers use rating scales to measure whether symptoms improve. Two of the most common are the Positive and Negative Syndrome Scale (PANSS) and the Brief Psychiatric Rating Scale (BPRS). However, there is ongoing debate about whether these tools capture changes in symptoms as accurately as they could. If the scales are not sensitive enough, they may not accurately measure how well a treatment works.

Recent research shows that advanced statistical methods can help clean up messy data, by removing irrelevant or corrupted information, so it’s easier to spot real changes in symptoms and better understand how effective a treatment truly is.

In the EVIDENTIAL project, we will use individual participant data (IPD) from completed schizophrenia clinical trials shared through the Vivli platform. We will apply statistical models to refine how symptoms are grouped and measured. We will then re-run the treatment comparisons using these improved symptom scores to see whether the medications appear more or less effective than originally reported.

Our goal is to understand whether these advanced methods can improve how treatment effects are measured. If they do, this research could help future trials detect meaningful changes more clearly and may guide better treatment decisions for people living with schizophrenia.