title: An examination of associations between the inability to taste phenylthiocarbamide (PTC) and clinical characteristics and trait markers in first-episode, nonaffective psychotic disorders.
abstract: Research findings are mixed as to whether or not the inability to taste phenylthiocarbamide (PTC) might represent an endophenotypic trait marker for schizophrenia. We hypothesized associations between PTC-tasting status and select clinical characteristics and trait markers in patients with psychotic disorders that, if present, would provide support for the inability to taste PTC as a trait marker. In a first-episode psychosis sample (n=93), we measured PTC tasting, family history of psychosis, age at onset of prodrome and psychosis, severity of positive and negative symptoms, global impairment in functioning, neurological soft signs, and four neurocognitive domains (verbal learning/memory, visual learning/memory, verbal working memory, and spatial working memory). Associations between PTC-non-tasting and clinical/neurocognitive variables were examined with χ(2) tests and independent samples t tests. Among participants, 67.7% tasted PTC in comparison to a strip of control paper, and 25.8% were non-tasters. Tasters and non-tasters did not show statistically significant differences with respect to family history, age at onset, severity of symptoms, neurological soft signs, or the four neurocognitive domains. In conjunction with other findings, it is unlikely that PTC-non-tasting is a trait marker of schizophrenia, though a conclusive study is warranted.
authors.affiliation: The George Washington University School of Medicine and Health Sciences, Department of Psychiatry and Behavioral Sciences, Washington, DC 20037, USA. mcompton@mfa.gwu.edu
authors.forename: Michael T
authors.initials: MT
authors.lastname: Compton
authors.forename: Dawn F
authors.initials: DF
authors.lastname: Ionescu
authors.forename: Beth
authors.initials: B
authors.lastname: Broussard
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Cristofaro
authors.forename: Stephanie
authors.initials: S
authors.lastname: Johnson
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Haggard
authors.forename: Amy A
authors.initials: AA
authors.lastname: Potts
authors.forename: Claire Ramsay
authors.initials: CR
authors.lastname: Wan
authors.forename: Elaine F
authors.initials: EF
authors.lastname: Walker
mesh_terms: D000293:Adolescent; D000328:Adult; D000341:Affective Disorders, Psychotic / Q000150:complications*; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D009460:Neurologic Examination; D010670:Phenylthiourea; D011569:Psychiatric Status Rating Scales; D012189:Retrospective Studies; D013651:Taste Disorders / Q000175:diagnosis* / Q000209:etiology*; D014706:Verbal Learning; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010670:Phenylthiourea
keywords: Endophenotype; First-episode psychosis; Phenylthiocarbamide (PTC); Psychosis; Schizophrenia