Jan 1, 1986

The familial sporadic classification: its power for the resolution of genetic and environmental etiologic factors

Journal of Psychiatric Research
L J EavesS C Schulz


An increasingly popular research method for identifying etiologic heterogeneity in psychiatric illness has been to compare the frequency of a risk factor in affected individuals with no affected relatives (sporadic cases) and in affected individuals with one or more affected relatives (familial cases). This paper presents a power analysis of this familial vs sporadic method, assuming a multifactorial model with a normally distributed liability to illness resulting from the additive effect of polygenes and multiple environmental factors. Various parameter estimates for a risk factor that identifies a component of either the genetic or the environmental contribution to disease liability are examined. Almost without exception, large sample sizes of probands and relatives need to be studied to have a substantial probability of detecting etiologic heterogeneity. The required sample size decreases dramatically when monozygotic twins are studied. If the multifactorial model accurately depicts the etiology for psychiatric disorders, these results suggest that the familial versus sporadic design is useful only when pursued in the context of large sample nuclear family studies or studies of monozygotic twins.

  • References9
  • Citations36


  • References9
  • Citations36

Mentioned in this Paper

Chronic Disease
Fetishism (Psychiatric)
Research Methodology
Genetic Markers
Theoretical Study
Diseases in Twins
Psychiatry Specialty
Family Investigation, NOS
Exogenous Factors

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Bone Marrow Neoplasms

Bone Marrow Neoplasms are cancers that occur in the bone marrow. Discover the latest research on Bone Marrow Neoplasms here.

IGA Glomerulonephritis

IgA glomerulonephritis is a chronic form of glomerulonephritis characterized by deposits of predominantly Iimmunoglobin A in the mesangial area. Discover the latest research on IgA glomerulonephritis here.

Cryogenic Electron Microscopy

Cryogenic electron microscopy (Cryo-EM) allows the determination of biological macromolecules and their assemblies at a near-atomic resolution. Here is the latest research.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

LRRK2 & Immunity During Infection

Mutations in the LRRK2 gene are a risk-factor for developing Parkinson’s disease. However, LRRK2 has been shown to function as a central regulator of vesicular trafficking, infection, immunity, and inflammation. Here is the latest research on the role of this kinase on immunity during infection.

Antiphospholipid Syndrome

Antiphospholipid syndrome or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by the presence of antibodies directed against phospholipids.

Meningococcal Myelitis

Meningococcal myelitis is characterized by inflammation and myelin damage to the meninges and spinal cord. Discover the latest research on meningococcal myelitis here.

Alzheimer's Disease: MS4A

Variants within membrane-spanning 4-domains subfamily A (MS4A) gene cluster have recently been implicated in Alzheimer's disease by recent genome-wide association studies. Here is the latest research.