A preliminary, randomized, double-blind, placebo-controlled trial of l-carnosine to improve cognition in schizophrenia

Schizophrenia Research, 10/26/2012

Chengappa KNR et al. – The authors conducted a preliminary study to test the hypothesis that l–carnosine, an antioxidant and anti–glycation agent which is co–localized and released with glutamate would improve executive dysfunction, a cognitive domain associated with glutamate. The preliminary findings suggest that l–carnosine merits further consideration as adjunctive treatment to improve executive dysfunction in persons with schizophrenia.


  • Seventy-five symptomatically stable adults with chronic schizophrenia were randomly assigned to l-carnosine as adjunctive treatment (2g/day) or a matched placebo in a double-blind manner for 3months.
  • Cognitive domains (executive dysfunction, memory, attention and motor speed) were assessed using a computerized battery at baseline, 4 and 12weeks, along with psychopathology ratings and safety parameters.


  • The l-carnosine group performed significantly faster on non-reversal condition trials of the set-shifting test compared with placebo but reversal reaction times and errors were not significantly different between treatments.
  • On the strategic target detection test, the l-carnosine group displayed significantly improved strategic efficiency and made fewer perseverative errors compared with placebo.
  • Other cognitive tests showed no significant differences between treatments.
  • Psychopathology scores remained stable.
  • The carnosine group reported more adverse events (30%) compared with the placebo group (14%).
  • Laboratory indices remained within acceptable ranges.

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