Carnosine and Cognitive Training in Schizophrenia
Condition: Schizophrenia
MeSH terms: Schizophrenia
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      This is a double-blind placebo-controlled trial to evaluate the effects of the combination of
      a cognition enhancing drug, i.e carnosine, with cognitive training in patients with
      schizophrenia. All participants will receive the same cognitive training sessions and will be
      randomised to either carnosine or placebo for the duration of the combined treatment period
      (2 weeks). Before combined training and carnosine/placebo, there is a two-week
      carnosine/placebo only phase to examine the effects of carnosine alone on functioning without
      training.
    

Detailed description: 
      Compromised cognitive functioning is a core feature of schizophrenia, yet it remains a major
      unmet need in the treatment of schizophrenia. Current available therapeutic approaches to
      enhance cognition in schizophrenia - either pharmacological or non-pharmacological (for a
      review) have yielded, at best, only modest results with questionable retention of the
      cognitive benefits and generalization of the effects into functional benefit. The
      investigators propose a novel approach to enhance cognition in schizophrenia: combining a
      food supplement with cognitive training, rather than using each intervention alone.

      Aim is to test the primary hypothesis that the combination of L-carnosine with cognitive
      training will significantly increase the performance of patients with schizophrenia on memory
      and learning training tasks compared to pairing cognitive training with placebo. The
      investigators will also test the secondary hypotheses that in the group receiving L-carnosine
      increased performance is due to a greater learning rate. Carnosine has antioxidant and
      antiglycating action and is found in food and the human body. The investigator's choice is
      guided by several considerations but, primarily the evidence that L-carnosine has
      neuroprotective effects through its antioxidant features. Briefly, the investigators propose
      that alterations in metabolism in several neurotransmitter systems (particularly glutamate)
      can both contribute to, and be modified by, oxidative stress, and therefore antioxidant
      administration could positively affect neurotransmitter role in synaptic plasticity, learning
      and memory.

      Carnosine has shown some improvements in cognitive outcomes in autism (Chez et al, 2002) and
      schizophrenia (Chengappa et al; unpublished). Chez used oral doses of 800mg/d for 8 weeks;
      while the latter study used oral doses of 2000mg for 4 weeks showing positive effects. Hence
      this is the dose and delivery route that will be used. The investigators have opted for 4
      weeks course following broadly from these two studies. Carnosine is widely available from
      health and food supplement shops in the UK and US retail market in highly pure form; is a
      naturally occurring in food and the human body; and is well-tolerated and has a benign
      side-effect profile, as shown from previous trials, and is therefore not associated with any
      potential risks.
    

Intervention name(s): L-Carnosine; Placebo; Cognitive Training
Intervention type(s): Drug; Drug; Behavioral
Intervention description(s): Cognitive Training for 2 weeks
Other intervention name(s): Carnosine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: L-Carnosine; Schizophrenia; Psychosis; Cognition