title: The effect of catechol-O-methyltransferase polymorphisms on pain is modified by depressive symptoms.
abstract: BACKGROUND
  Variations within the catechol-O-methyltransferase (COMT) gene have been associated with pain severity in temporomandibular disorders (TMDs). Psychological factors such as personal conflicts, life stress and depression, are well known to be associated with onset, severity and chronicity of pain disorders.
  
  
  OBJECTIVE
  We hypothesized that the relationship between the COMT gene and TMD pain is modified by depressive symptoms.
  
  
  METHODS
  Cross-sectional data from the population-based Study of Health in Pomerania (SHIP) in Germany were used to estimate additive interactions between depressive symptoms and 22 single-nucleotide polymorphisms (SNPs) of the COMT gene and the neighbouring thioredoxin reductase 2 (TXNRD2) gene on TMD pain. All participants were Caucasian subjects from a rural area in Northeast Germany. After exclusion of 79 subjects with antidepressant medication, 29.9% of the remaining 3904 subjects reported lifetime depressive symptoms. TMD pain was assessed by a standardized clinical examination. Among various TMD signs, only those that assessed muscle or joint pain on palpation were used as recommended.
  
  
  RESULTS
  Six SNPs from the first of three COMT/TXNRD2 haploblocks interacted with depressive symptoms on TMD pain (smallest p-value: 2.7 × 10(-10) ). In subjects without depressive symptoms, rs5993882 was identified as the SNP most likely to be related to TMD pain. In subjects with symptoms of depression, rs1544325 was the corresponding top COMT SNP.
  
  
  CONCLUSIONS
  Our results indicate that variants within the COMT gene are associated with pain perception. However, this association is highly moderated by the absence or presence of lifetime depressive symptoms.
authors.affiliation: Unit of Oral and Systemic Diseases, Department of Prosthodontics, Gerodontology and Dental Materials, Center of Oral Health, University of Greifswald, Greifswald, Germany. schwahn@uni-greifswald.de
authors.forename: C
authors.initials: C
authors.lastname: Schwahn
authors.forename: H J
authors.initials: HJ
authors.lastname: Grabe
authors.forename: H
authors.initials: H
authors.lastname: Meyer zu Schwabedissen
authors.forename: A
authors.initials: A
authors.lastname: Teumer
authors.forename: C O
authors.initials: CO
authors.lastname: Schmidt
authors.forename: C
authors.initials: C
authors.lastname: Brinkman
authors.forename: T
authors.initials: T
authors.lastname: Kocher
authors.forename: M
authors.initials: M
authors.lastname: Nauck
authors.forename: H
authors.initials: H
authors.lastname: Völzke
authors.forename: R
authors.initials: R
authors.lastname: Biffar
authors.forename: O
authors.initials: O
authors.lastname: Bernhardt
mesh_terms: D000328:Adult; D000368:Aged; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D059350:Chronic Pain / Q000209:etiology / Q000235:genetics* / Q000523:psychology; D003863:Depression / Q000235:genetics* / Q000523:psychology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012720:Severity of Illness Index; D013315:Stress, Psychological / Q000235:genetics / Q000523:psychology; D013705:Temporomandibular Joint Disorders / Q000150:complications / Q000235:genetics / Q000523:psychology
chemical_list: D002394:Catechol O-Methyltransferase