title: Serum testosterone levels are related to cognitive function in men with schizophrenia.
abstract: BACKGROUND
  Sex steroids such as oestrogen and testosterone are potent neurodevelopmental hormones that also play a role in neuromodulation and neuroprotection of the mature brain. Sex steroid hormones may also be involved in the pathophysiology of schizophrenia as reduced circulating sex steroid levels and changes in brain sex steroid receptors are found in people with schizophrenia compared to controls. In men with schizophrenia, recent studies have documented an inverse correlation between serum testosterone and negative symptoms. Our study sought to confirm whether men with schizophrenia had lower levels of testosterone relative to controls and to determine whether lower testosterone levels were related to higher symptom severity and impaired cognition.
  
  
  METHODS
  Circulating serum hormone levels (testosterone, oestrogen, and prolactin), cognitive function and symptoms were assessed in 29 chronically ill men with schizophrenia or schizoaffective disorder. Twenty healthy men were recruited as a comparison group. A series of regression analyses were performed to determine the extent to which circulating sex steroid hormone levels predict cognition and symptoms in men with schizophrenia.
  
  
  RESULTS
  We did not find a significant difference in serum testosterone levels between groups. However, circulating testosterone levels significantly predicted performance on verbal memory, processing speed, and working memory in men with schizophrenia. With the exception of an effect of oestrogen on verbal memory, circulating sex steroid levels did not predict cognitive function in healthy men. Testosterone levels were not related to positive or negative symptom severity, but testosterone influenced excitement/hostility levels in our schizophrenia sample.
  
  
  CONCLUSIONS
  The results suggest that circulating sex steroids may modulate cognitive deficits associated with schizophrenia.
authors.affiliation: Schizophrenia Research Institute, Darlinghurst, New South Wales (NSW), Australia; Neuroscience Research Australia, Randwick, NSW, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Moore
authors.forename: M
authors.initials: M
authors.lastname: Kyaw
authors.forename: A
authors.initials: A
authors.lastname: Vercammen
authors.forename: R
authors.initials: R
authors.lastname: Lenroot
authors.forename: J
authors.initials: J
authors.lastname: Kulkarni
authors.forename: J
authors.initials: J
authors.lastname: Curtis
authors.forename: M
authors.initials: M
authors.lastname: O'Donnell
authors.forename: V J
authors.initials: VJ
authors.lastname: Carr
authors.forename: C
authors.initials: C
authors.lastname: Shannon Weickert
authors.forename: T W
authors.initials: TW
authors.lastname: Weickert
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use; D003072:Cognition Disorders / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D004967:Estrogens / Q000097:blood; D006801:Humans; D006966:Hyperprolactinemia / Q000139:chemically induced; D008297:Male; D008569:Memory Disorders / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011388:Prolactin / Q000097:blood; D011618:Psychotic Disorders / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology / Q000523:psychology; D012559:Schizophrenia / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D063189:Symptom Assessment; D013739:Testosterone / Q000097:blood*; D014706:Verbal Learning / Q000502:physiology*; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D004967:Estrogens; D013739:Testosterone; D011388:Prolactin
keywords: Memory; Negative symptoms; Processing speed; Schizophrenia; Testosterone; Working memory