Genetic Study of Schizophrenia

Completed

• Conditions: Schizoaffective Disorder; Schizophrenia

• Registration Number: NCT00001486
• Lead Sponsor: National Institute of Mental Health (NIMH)

Brief Summary

This large ongoing study at NIMH investigates the neurobiology of schizophrenia by identifying susceptibility genes, evaluating their impact on brain function to better understand how to treat and prevent this illness.

Detailed Description

Objective: Schizophrenia is a complex genetic disorder which likely involves many genes each producing a slight increase in risk. Finding weak-acting genes in complex genetic disorders has been challenging and will likely require a number of approaches and large clinical samples. Several strategies have emerged recently that appear to markedly improve the power of genetic studies for detecting such genes. These include using association (rather than linkage) and using intermediate phenotypes in addition to DMS-IV diagnosis.

Study Population: We propose to take advantage of these techniques by studying quantitative traits related to schizophrenia in patients, siblings, and controls.

Design: We will employ an association design, rather than linkage. Traits will include quantifiable neurobiological variables that have been implicated previously as possible phenotypes related to schizophrenia. These include tests of attention and cognition.

Outcome Measure: We will use several statistical methods to show that specific genetic polymorphisms affect these phenotypes, including case control and family based association studies.

Study Timeline

• Study Start: 1995-07-15
• Study First Submitted: 1999-11-03
• Study First Submitted QC: 1999-11-03
• Study First Posted: 1999-11-04
• Status Verified: 2025-03-17
• Last Update Submitted: 2025-05-17
• Last Update Posted: 2025-05-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 4914

Inclusion Criteria

Not provided

Exclusion Criteria

They will not be eligible if:

• They have history of DSM IV-R psychiatric diagnosis or severe chronic medical illness at the time of the study.
• They have a history of any (excepting nicotine-related) DSM5-defined moderate to severe substance use disorder (or DSM-IV-defined substance dependence).
• They have a cumulative lifetime history of any (excepting nicotine-related) DSM5-defined mild substance use disorder (or any DSM-IV-defined substance abuse), either in excess of 5 years total or not in remission for at least 6 months.
• They may not be eligible for the 2-day or 1-day study if they have a first-degree relative with history of schizophrenia spectrum disorders. However, they may be included in the SCID_DNA or case control analyses.
• Healthy volunteers must be free of learning disabilities.
• NIMH employees/staff and their immediate family members will be excluded from the study per NIMH policy.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Genetic Polymorphisms affect phenotypes	At time of study participation	genotyping analysis

Secondary Outcome Measures

Name	Time	Method
PANSS, AIMS, GAF	At time of study participation	PANSS, AIMS, GAF

Trial Locations

Locations (1)

National Institutes of Health Clinical Center; 🇺🇸 Bethesda, Maryland, United States