• adoption studies;
  • DSM-III-R;
  • family studies;
  • heredity;
  • personality disorders;
  • twin studies

The concept of personality disorders is based on deviant personality traits in both the DSM-III-R and ICD-10 classifications. A diagnosis of personality disorder can be made reliably with structured interviews. Many individuals are diagnosed with more than one personality disorder, and other mental disorders are often found at the same time. Among the 11 personality disorders in DSM-III-R, only the schizotypal, borderline, and antisocial have been examined to any considerable extent for gene effects. The problems of studying heredity are here demonstrated for borderline and antisocial personality disorders. Recommendations are given as to strategies for further study of heredity in personality disorders.