Dissecting Immunological and Autoimmune Mechanisms of Neuropsychiatric Diseases

The goal of this observational cohort study is to investigate the role of immune system in neuropsychiatric symptoms (NPS) and to identify immunological biomarkers that may improve the diagnosis, prognosis, and future treatment of immune-related neuropsychiatric disorders in individuals aged 16-100 years with suspected immune-mediated neuropsychiatric symptoms and matched control participants without neuropsychiatric symptoms.

The main questions it aims to answer are what immunological mechanisms are associated with neuropsychiatric symptoms across a range of neurological, psychiatric, autoimmune, infectious, and inflammatory conditions. Also, if immunological biomarkers can be identified that may support the diagnosis, prognosis, and future treatment of neuropsychiatric disorders in which the immune system may play a role.

Participants will provide a blood sample for immunological analysis and may optionally provide a cerebrospinal fluid (CSF) sample if a suitable previously collected sample is not available. Researchers may also analyse existing clinical and biological samples where available. Participants will provide demographic and clinical information, allow access to relevant medical record data, and may optionally provide additional blood samples, up to four times within one year, for further biomarker and immunological analyses.

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Key information

Conditions

Neuropsychiatric Symptom Autoimmune Diseases Autoimmune Diseases of the Nervous System Behavior Behavioral Symptoms Catatonia Immune System Diseases Inflammation Mental Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathologic Processes Pathological Conditions, Signs and Symptoms Psychotic Disorders Schizophrenia Spectrum and Other Psychotic Disorders Signs and Symptoms

Age range

16 year–100 year

Sex eligibility

All sexes

Study type

Observational

Primary location

King's College Hospital, London, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Participants with Neuropsychiatric symptoms

Age 16-100.
Current or previous neuropsychiatric symptoms within the last year.
Suspicion of immunological contribution to the aetiology of their neuropsychiatric symptoms.

Control Participants

Age 16-100.
No current or previous self-report of neuropsychiatric symptoms within the last year.

Optional Lumbar Puncture only:

Documented full blood count within the last 3 months with no clinically significant abnormalities.

Exclusion criteria

All Participants:

Unacceptable risk of harm to participant or study staff due to risk of behavioural disturbance.
Inability to have blood tests.

Optional Lumbar Puncture only:

Significant lower spinal deformity (such as spina bifida), injury, or disease (such as stenosis) or previous lower spinal surgery.
Antiplatelet or anticoagulant therapy within the 14 days prior to Lumbar Puncture procedure.
Known or suspected clotting disorder.
Clinically significant abnormality in full blood count.
Known or suspected raised intracranial pressure, assessed by study clinician.
Known or suspected allergy to local anaesthetic agent or an ingredient of the anaesthetic solution.
History of chronic or recurrent headaches, in the opinion of the investigator.

Treatment and study plan

Primary outcomes

Neuronal Autoantibodies

Time frame: From enrolment through to 1 year of follow-up.

Differences in the prevalence, subtype, and functional characteristics of neuronal autoantibodies in serum and cerebrospinal fluid between participants with neuropsychiatric symptoms (NPS) and matched control participants.

Sponsors and collaborators

Lead sponsor

King's College London

Other

Collaborators

Francis Crick Institute
King's College Hospital NHS Trust
South London and Maudsley NHS Foundation Trust

Registry information

Acronym: DIAMOND

Important dates

Study start: 2026
Primary completion: 2036
Study completion: 2036
First posted: Aug 27, 2026
Registry last updated: Aug 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed