Patients with difficult-to-treat depression do not exhibit an increased frequency of CYP2D6 allele duplication

Á Háber, O. Rideg, P. Osváth, S. Fekete, F. Szücs, A. Fittler, G. L. Kovács, A. Miseta, L. Botz

Research output: Contribution to journalArticle

4 Citations (Scopus)


Introduction: The insufficient response of patients to antidepressant medications may result from several factors, including altered drug metabolism. CYP2D6 genotyping may help assess the possible factors that contribute to difficult-to-treat depression. The aim of our study was to determine the frequency of CYP2D6 allelic variants and the prevalence of predicted CYP2D6 phenotypes in patients who were suffering from difficult-to-treat depression and compare the data with those for the healthy population of Hungary. Methods: 55 patients who failed to respond to 2 or more adequate trials of different CYP2D6-dependent antidepressants were selected for genotyping. Results: The prevalence of the predicted CYP2D6 phenotypes in the patient population was 1.8% for the UMs, 80.0% for EMs, 3.6% for IMs and 14.5% for PMs compared with 1.9% for UMs, 83.3% for EMs, 6.5% for IMs and 8.3% for PMs in the Hungarian population. Discussion: The CYP2D6 allele frequencies and the predicted phenotype distributions in patients with difficult-to-treat depression were not significantly different to those found in the healthy population of Hungary. The cumulative frequency of the CYP2D6*1XN,*2XN and*35XN alleles was 0.9% in the patient population suggesting that CYP2D6 duplication or multiplication does not play a significant role in antidepressant pharmacotherapy failure in this patient sample. The cumulative frequency of the non-functional alleles (33.5%) and the prevalence of the genetically determined PM phenotype (14.5%) were relatively high in the patient group. These figures draw attention to the possibility of unrecognised and non-reported side effects and non-adherence to drug treatment.

Original languageEnglish
Pages (from-to)156-160
Number of pages5
Issue number4
Publication statusPublished - Jun 14 2013


  • CYP2D6 allele duplication
  • CYP2D6 genotyping
  • difficult-to-treat depression
  • major depressive disorder
  • ultrarapid metaboliser phenotype

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Pharmacology (medical)

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