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PPiP2 is a cross-sectional study conducted in over 40 NHS mental health trusts, across England and Scotland. It uses live-based assay to test serum of study participants with psychosis for NMDAR, LGI1, GABA-A and CASPR2. PPiP2 will continue to recruit study participants until the end of November 2027.

Image of a female researcher in a lab looking through a microscope. © Image by Trust Tru Katsande from Unsplash

PPIP2 Study

The PPiP2 study includes adult (16-70 yrs) participants from NHS mental health services who are experiencing their first episode of psychosis or relapse of psychosis symptoms. For participants who relapsed there needs to be a period of at least six months of remission prior to the current episode. Patients with any other neurological disorder would not be included in the study.

Local researchers and clinicians, based in participating NHS Trusts are approaching potential participants from both inpatient and community services. If the potential participant is eligible for the study, the researcher or clinician will take informed consent to participate in PPiP2 and will collect a small sample of blood. This sample will be tested for at least four anti-neuronal antibodies, namely NMDAR, LGI1, CASPR2 and GABA-A. Apart from basic demographic and clinical data no further assessments are required.

Test results will be communicated to the local research team and the participant's psychiatrist.  If results are negative no action is required. However, it is advised to refer patients with identified anti-neuronal membrane antibody in their serum to a neurologist. This can be a neurologist with special interest in neuroimmunology based in one of the SINAPPS2 trial site located in multiple hospitals across England.

If you, or someone you care for, is interested in taking part in the PPiP2 study, you can find more information clicking here.

Clinicians who would like to refer patients to PPiP2 could contact either the local PPiP2 research team  or the PPIP2 central team (

The PPiP2 study is funded by Medical Research Council, Developmental Pathway Funding Scheme: MR/N019067/1 and it is approved by the East of England (Norfolk) Local Research Ethics Committee (Reference 12/EE/0307).

 Tile, selected study documents