There is preliminary evidence that
transcranial direct current stimulation(
tDCS) may improve symptoms and cognitive function in
schizophrenia, but the generalizability of these results needs further investigation. We present a study of the effects of active vs.
sham tDCS on cognition and symptoms in a sample of 45 Chinese patients with
schizophrenia who showed significant cognitive deficits and were treated for 10 sessions with active or
sham tDCS. Psychiatric symptoms were assessed by PANSS scores, and
cognitive symptoms assessed by MATRICS battery and other tests. There were no differences between cognitive or symptom scores between subjects treated with active vs.
sham tDCS tested within 1-2 days after the end of the 10th session. However, two weeks later subjects treated with active
tDCS showed significantly more improvements on MATRICS Speed of Processing domain. MATRICS Overall Composite and a CogState measure related to accuracy on a 1-back working memory task were improved at two weeks in statistical tests without multiple corrections. The improvement in cognitive test scores 2 weeks after the last
tDCS session, suggests longer term effects may be related to changes in neuroplasticity induced by 10 sessions of
tDCS. The lack of significant changes in cognition shortly after the completion of 10
tDCS sessions contrasts with our earlier positive findings in U.S. patients with
schizophrenia.