Malhotra's investigation, published in the November Molecular Psychiatry, yields no association between the 7-repeat version of D4DR and novelty seeking in a group of 193 Finnish men.
In an additional examination of 138 alcoholic Finnish men, many of whom displayed high levels of novelty seeking, the D4DR variation appeared slightly more often among those with the lowest scores on that personality trait, the researchers hold.
Kidd's team, which presented its findings this week at the American Society of Human Genetics annual meeting in San Francisco, assessed D4DR variations in 14 populations from Africa, Europe, the Middle East, East Asia, North America, and South America.
Studies that discerned a link between this D4DR form and novelty seeking took place in Israel and the United States, where the gene is relatively frequent, they state.
Volunteers scoring high in novelty seeking were much more likely to bear a slightly longer form of the D4DR gene than low novelty seekers, the scientists maintain.
No single trait of the five showed an association with any D4DR variation.
However, prior studies have found that the same patients do not exhibit a preponderance of any particular form of the D4DR gene.
It may be useful to reexamine D4DR in groups of schizophrenics to find how often the longer variety occurs together with novelty seeking, Cloninger contends.