Transcranial Direct Current Stimulation (tDCS) As A Treatment For Cigarette Craving and Cognitive Deficits in Schizophrenic

The Brief Questionnaire on Smoking Urges (QSU-Brief) was used to measure cigarette cravings. Scores ranged from a minimum of 1 ("Strongly Disagree") to a maximum of 7 ("Strongly Agree") and were determined by self-reported responses to 10 statements about having cravings for smoking. Scores closer to 1 after treatment would indicate a better outcome. Responses to each of the 10 items in the scale were summed for one total score. With 10 items on this scale with a range of scores from 1 to 7, on each occasion of rating the minimum score would be 7 and the maximum score would be 70.

The MATRICS Consensus Cognitive Battery (MCCB) was used to measure cognitive performance. Seven Domain scores and a Composite score are calculated by the proprietary MCCB Computer Scoring Program from raw scores on 10 individually administered subtests. We used the revised MCCB program (beta version) which allows for calculation of Domain and Composite scores with missing data. The Domain T-scores are percentile-ranked and range from <20 (<0.1 percentile) to >80 (>99.9 percentile). The Composite scores are also percentile-ranked and range from <213 (T<20, <0.1 percentile) to >487 (T>80, >99.9 percentile). Higher scores after baseline represent better outcomes. Here we report difference scores from post-treatment and baseline with positive difference scores representing better outcomes.

The Positive and Negative Syndrome Scale (PANSS) was used to measure psychiatric symptoms. Item scores ranged from 1 (Absent) to 6 (Severe) for symptoms on the Positive Scale (total subscale range: 7-42), the Negative Scale (total subscale range: 7-42), and the General Psychopathology Scale (total subscale range:16-96). All three subscales were summed for the PANSS total score (total scale range: 30-180). Scores closer to 30 after baseline represented better outcomes. Here we report difference scores from post-treatment and baseline with negative difference scores representing better outcomes.