Behavior Genetics. 31(5):455, SEPTEMBER 2001 Issn Print: 0001-8244 Publication Date: September 2001 Print A Twin Study of the Genetics of Fear Conditioning. John Hettema;Peter Annas;Michael Neale;Mats Fredrikson;Kenneth Kendler; + Author Information 1Virginia Institute for Psychiatric and Behavioral Genetics, Department of Psychiatry, Virginia Commonwealth University, Richmond, VA. 2Roche AB, Stockholm, Sweden. 3Department of Psychology, Uppsala University, Uppsala, Sweden. Checking for direct PDF access through Ovid Abstract Abstract unavailable for this article.