Using biological indices to classify schizophrenia and other psychotic patients

S. R. Sponheim, W. G. Iacono, P. D. Thuras, M. Beiser

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Although classification of mental disorders using more than clinical description would be desirable, there is scant evidence that available laboratory tests (i.e. biological indices) would provide more valid classifications than current diagnostic systems (e.g. DSM-IV). We used cluster analysis of four biological variables to classify 163 psychotic patients and 83 nonpsychiatric comparison subjects. Analyses revealed a three-cluster solution with the first cluster reflecting electrodermal deviance, the second cluster representing nondeviant biological function, and the third cluster reflecting increased nailfold plexus visibility and ocular motor dysfunction. To assess the construct validity of proband clusters we examined ocular motor performance in 156 first-degree relatives as a function of proband cluster membership. First-degree relatives of third cluster probands exhibited worse ocular motor performance than relatives of other cluster probands. Additionally, better classification sensitivity and specificity were obtained for the relatives when they were grouped by proband cluster than by proband DSM-IV diagnosis. When a single proband characteristic (i.e. eyetracking performance) was used to group relatives, classification sensitivity and specificity failed to significantly increase over grouping by proband DSM-IV diagnosis. Multivariate biologically defined clusters may offer an advantage over DSM-IV classification when examining nosology and etiology of psychotic disorders.

Original languageEnglish (US)
Pages (from-to)139-150
Number of pages12
JournalSchizophrenia Research
Issue number3
StatePublished - Jul 1 2001

Bibliographical note

Funding Information:
This work was supported in part by the Psychology and Psychiatry Services at the Veterans Affairs Medical Center, Minneapolis, Minnesota, and by grants from the National Institute of Mental Health (MN44643), Medical Research Council of Canada, and the National Health and Welfare Research Directorate of Canada. Presented in part at the International Congress on Schizophrenia Research, Santa Fe, New Mexico, April 1999.


  • Genetic vulnerability
  • Nosology
  • Ocular motor function
  • Psychosis
  • Schizophrenia


Dive into the research topics of 'Using biological indices to classify schizophrenia and other psychotic patients'. Together they form a unique fingerprint.

Cite this