title: Delusional disorder: molecular genetic evidence for dopamine psychosis.
abstract: Since delusional disorder is characterized by mono-symptomatic paranoid symptoms, it can be a good clinical model for investigating the dopaminergic mechanism responsible for paranoid symptoms. We examined neuroleptic responses, plasma homovanillic acid (pHVA) and genes of the dopamine receptor (DR) and its synthesizing enzyme (tyrosine hydroxylase: TH) in patients with delusional disorder and compared them with those of schizophrenic patients and healthy controls.
  
  
  RESULTS
  (1) A relatively small dose of haloperidol was more effective for delusional disorder than for schizophrenia. (2) The pretreatment level of pHVA was higher in patients with persecution-type, but not in those with jealousy-type delusional disorder, compared with age- and sex-matched controls. This increased pHVA level was decreased eight weeks after successful haloperidol treatment. (3) The genotype frequency of the DRD2 gene Ser311Cys was significantly higher in patients with persecution-type delusional disorder (21%), compared with schizophrenic patients (6%) or controls (6%). (4) Patients homozygous for the DRD3 gene Ser9Ser had higher pretreatment levels of pHVA than those heterozygous for Ser9Gly. (v) A significant positive correlation was found between the polymorphic (TCAT)(n) repeat in the first intron of the TH gene and pretreatment levels of pHVA in delusional disorder. We suggest that delusional disorder, especially the persecution-type, includes a "dopamine psychosis," and that polymorphism of the DRD2, DRD3 and/or TH gene is part of the genetic basis underlying the hyperdopaminergic state that produces paranoid symptoms. Further studies on a large sample size are required.
authors: Department of Neuropsychiatry, Faculty of Medicine, Kagawa Medical University, Kagawa, Japan. neuropsy@kms.ac.jp
authors: Kiyoshi
authors: K
authors: Morimoto
authors: Ryosuke
authors: R
authors: Miyatake
authors: Mitsuo
authors: M
authors: Nakamura
authors: Takemi
authors: T
authors: Watanabe
authors: Toru
authors: T
authors: Hirao
authors: Hiroshi
authors: H
authors: Suwaki
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D005260:Female; D005838:Genotype; D006719:Homovanillic Acid / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000097:blood / Q000188:drug therapy / Q000235:genetics* / Q000523:psychology; D011954:Receptors, Dopamine / Q000235:genetics*; D012563:Schizophrenia, Paranoid / Q000097:blood / Q000188:drug therapy / Q000235:genetics* / Q000523:psychology
chemical_list: D014150:Antipsychotic Agents; D011954:Receptors, Dopamine; D006719:Homovanillic Acid