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OpenTrials
Completed

NCT Number: NCT05109065

Peripheral Immune System in Individuals With Schizophrenia

The investigators are seeking healthy volunteers and people with schizophrenia or schizoaffective disorder for a clinical study of the immune system in psychotic disorders. This is an observational study, to understand the ways in which the immune system may be contributing to the disease process.

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Key information

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Stanford University School of Medicine

Stanford, California, 94704, United States

About this study

Genetic studies have linked the number of copies coding for C4 protein to risk for schizophrenia. Studies examining the amount of mRNA, the molecules that point to how much C4 protein is likely being made, found more C4 mRNA in the brains from individuals with schizophrenia. Studies in mice have suggested that expressing more C4 protein in the brain, specifically the A-type of C4, can result in abnormalities in behavior. However, researchers have also found that pathways that involve this protein in the blood to be abnormal in individuals even before they develop schizophrenia and hypothesize these abnormalities change the blood brain barrier. In this work, the researchers are hoping to understand the ways in which C4 protein is abnormal in the peripheral blood and how this may be contributing to the disease process in hopes of finding new ways of helping individuals with schizophrenia and possibly other mental health disorders. A major goal of this study is to collect blood tissue for ongoing translational study of pathophysiological mechanisms of schizophrenia.

Interested participants will be asked a series of questions about their medical and mental health history, be able to provide informed consent, undergo a urine toxicology screen and be willing to provide a blood sample.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

for Subjects with schizophrenia and schizoaffective disorders:

  • Schizophrenia or schizoaffective disorder diagnosis verified by interview
  • Diagnosis or initiation of antipsychotic medication was within last 5 years

Inclusion criteria

for Healthy Controls:

  • No known diagnosis of schizophrenia or schizoaffective disorder
  • No history of depression, anxiety, bipolar disorder, PTSD, agoraphobia, panic disorder, or generalized anxiety disorder
  • Negative assessment for psychotic symptoms on day of interview

Exclusion criteria

(for both groups):

  • Participants have a history of bleeding disorders or are taking blood thinners.
  • Participants have a history of epilepsy, known genetic disorders
  • Immunocompromised state (eg., receiving immunosuppressive therapy, transplant).
  • History of brain-related disease (eg., stroke)
  • Any uncontrolled medical disorder such as cancer.
  • History of substance abuse or positive urine toxicology screen (including test for marijuana) on the day of the blood draw

Treatment and study plan

SCID (Standardized Clinical Interview for DSM-V)

Diagnostic Test

The Structured Clinical Interview for DSM-5 (SCID-5) is a semistructured interview guide for a clinician or trained mental health professional to diagnose major mental illnesses.

PSS (Perceived Stress Score)

Diagnostic Test

The Perceived Stress Scale (PSS) is the most widely used psychological instrument for measuring the perception of stress. It is a measure of the degree to which situations in one's life are appraised as stressful. Items were designed to tap how unpredictable, uncontrollable, and overloaded respondents find their lives. Demographic information will also be collected.

Urine Toxicology Screen

Diagnostic Test

Participants will be asked to provide a urine sample. Evidence of active substance abuse (marijuana, opioids, other non-prescription drugs) by the urine toxicology screen will disqualify participants from the study.

Vitals

Diagnostic Test

Height and weight will be measured in order to calculate BMI.

blood work

Diagnostic Test

A venipuncture will be performed for the purpose of collecting blood tissue for study.

PQ-B

Diagnostic Test

The Prodromal Questionnaire - Brief Version (PQ-B) is a self-report measure designed to identify people who may be experiencing psychotic symptoms when they do not have a schizophrenia diagnosis.

COVID Screening

Diagnostic Test

Questionnaire to assess risk of transmission of COVID-19.

Positive and Negative Syndrome Scale (PANSS)

Diagnostic Test

Instrument that is completed by clinical interviewer to measure symptom severity in individuals with psychotic disorders.

Primary outcomes

  1. Group comparison of C4 protein in immune cells

    Time frame: Day 1

    Measure the concentration of complement 4 protein in immune cells.

Secondary outcomes

  1. Body Mass Index and its relationship to C4 protein concentration

    Time frame: Day 1

    The relationship between body mass index, calculated from the measured height and weight of participants, and the primary outcome (C4 protein concentration) will be determined.

  2. C4 Gene Copy Number

    Time frame: Day 1

    Determine the C4 Gene Copy Number its relationship to C4 protein concentration in immune cells.

  3. C4 Activation

    Time frame: Day 1

    Measure activity of C4 protein and its relationship to the primary outcome.

  4. Relationship to symptom presentation

    Time frame: Day 1

    Explore the relationship between clinical severity scores (PANSS) and the primary outcome.

  5. Relationship to stress

    Time frame: Day 1

    Explore the relationship between perceived stress (PSS) and the primary outcome.

Sponsors and collaborators

Lead sponsor

Stanford University

Other

Registry information

Important dates

Study start
2021
Primary completion
2024
Study completion
2024
First posted
Nov 5, 2021
Registry last updated
Jun 6, 2025

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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