Is Varenicline a Useful Target Compound for Improving Cognitive Impairment in Schizophrenia?

Research Paper Title

Varenicline for cognitive impairment in people with schizophrenia: systematic review and meta-analysis.

Background

People with schizophrenia frequently have cognitive dysfunction, which does not respond to pharmacological interventions. Varenicline has been identified as a potential treatment option for nicotinic receptor dysfunction with a potential to treat cognitive impairment in schizophrenia.

Methods

The researchers conducted a systematic review of Pubmed, Embase, Psycinfo, CINAHL and the Cochrane Schizophrenia Trial Registry for randomised controlled trials of varenicline in people with schizophrenia for cognitive dysfunction.

They excluded trials among people with dementia. They then undertook a meta-analysis with the primary outcome of difference in change of cognitive measures between varenicline and placebo as well as secondary outcomes of difference in rates of adverse events.

They also conducted a sensitivity analysis on smoking status and study duration.

Results

The researchers included four papers in the meta-analysis (n = 339).

Varenicline was not superior to placebo for:

  • Overall cognition (SMD = -0.022, 95% CI -0.154-0.110; Z = -0.333; p = 0.739);
  • Attention (SMD = -0.047, 95% CI -0.199-0.104; Z = -0.613; p = 0.540);
  • Executive function (SMD = -0.060, 95% CI -0.469-0.348; Z =- 0.290; p = 0.772); or
  • Processing speed (SMD = 0.038, 95% CI -0.232-0.308; Z = 0.279; p = 0.780).

There was no difference in psychotic symptoms, but varenicline was associated with higher rates of nausea.

Sensitivity analyses for smoking status and study duration did not alter the results.

Conclusions

Within the present literature, varenicline does not appear to be a useful target compound for improving cognitive impairment in schizophrenia.

Based on these results, a trial would need over 2,500 participants to be powered to show statistically significant findings.

Reference

Tanzer, T., Shah, S., Benson, C., De Monte, V., Gore-Jones, V., Rossell, S.L., Dark, F., Kisely, S., Siskind, D. & Melo, C.D. (2019) Varenicline for cognitive impairment in people with schizophrenia: systematic review and meta-analysis. Psychopharmacology. doi: 10.1007/s00213-019-05396-9. [Epub ahead of print].

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