Magazine article Clinical Psychiatry News
Twin Studies Suggest Genetic Link to Impulsivity: A Factor in Many Psychiatric Ills. (Candidate Gene Identified)
MADRID -- Impulsivity, a core component of a number of psychiatric conditions, appears to be related to serotonin neurotransmission and may be influenced in part by a specific receptor gene, Dr. Frederic Moeller said at the World Psychiatric Association International Congress 2001.
A small study found elevated scores on a test of impulsivity in psychiatrically healthy individuals who had two copies of a specific allele of a gene that regulates the 5HT2A receptor, compared with those who had one or no copies, said Dr. Moeller of the University of Texas, Houston.
Impulsivity, which Dr. Moeller defined as "a predisposition toward rapid, unexplained reactions to internal or external stimuli, without regard to negative consequences to oneself or others, is a biopsychosocial construct that has both stable and unstable characteristics.
There is evidence that genetic variables at least in part account for it. One study of 57 monozygous and 49 dizygous twin pairs reared apart and 90 nontwin siblings showed that impulsivity as assessed by a personality questionnaire was significantly correlated in the monozygous twins but not in the others. In another study of 194 monozygous and 94 dizygous twin pairs, teacher and parent ratings found much higher correlations for impulsivity/hyperactivity in the monozygous pairs, compared with the dizygous ones. …