Genetic Tests Could Indicate Personality Disorder

Genetic tests using blood samples are already used to diagnose some diseases and even personalize treatment. It is possible to develop similar tests that reveal a person's potential to become dependent on nicotine or marijuana or have an antisocial personality disorder.
These tests would not dictate who would become substance dependent or have behavioral problems, as genes do not function in isolation, but are influenced by other genes and environmental factors. In a recent study, the researchers found certain differences in the genes of people with a history of smoking compared to those without such a history. In all, 579 genes were more expressed and 584 genes were less expressed in people who had smoked.
The technique used to analyze blood is called transcriptional profiling, said Anup Madan, UI adjunct assistant professor of neurosurgery and an assistant professor at the Institute of Systems Biology in Seattle (WA, USA). Transcription profiling involves looking at all the genes--nearly 30,000 of them--at one time. We label all the expressed genes by fluorescent tags, and changes in fluorescence intensity are used to identify differential gene expression.
The study was reported by University of Iowa (UI; Iowa City, IA, USA) scientists in the March 6, 2007, online edition of the American Journal of Molecular genetics. Our study suggests that analyzing the expression of genes in blood could indicate whether a person is susceptible to having a behavioral disorder. Having a particular gene expression change does not by itself predict that a person will act a certain way. However, it can indicate who might have a greater biological basis for engaging in behaviors such as smoking and alcohol or marijuana use, said the study's lead author Robert Philibert, M.D., Ph.D., professor of psychiatry in the UI Roy J. and Lucille A. Carver College of Medicine. What matters most is not whether you have a particular gene but whether the gene is expressed, and what other environmental factors may be at play. Genetic variation in and of itself is not deterministic, he added.
Our study suggests that analyzing the expression of genes in blood could indicate whether a person is susceptible to having a behavioral disorder. Having a particular gene expression change does not by itself predict that a person will act a certain way. However, it can indicate who might have a greater biologic basis for engaging in behaviors such as smoking and alcohol or marijuana use, Professor Philibert said.


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Institute of Systems Biology in Seattle
University of Iowa