Device: LB 2000, 100 Hz, 2mS, <1.5 mA, electrodes behind the ears at the mastoid process
Bianco, Faust. Ph.D. dissertation, The University of Tulsa
Prior to clinical trials the literature of CES for chemical dependency was subjected to meta-analysis. Initially 180 studies on CES from 1964 through 1987 were reviewed. 8 studies provided the necessary information to calculate means and standard deviations for meta-analysis.
The largest effect sizes pertained to the primary withdrawal symptoms of drug use, drug craving, and anxiety specifically among methodone users. In addition the results showed effect sizes beyond that of a placebo effect in several studies relating to anxiety as a secondary withdrawal symptom. However, some studies that considered anxiety as a secondary withdrawal symptom were below the placebo effect level.
The analysis displayed an average effect size of 0.940 SD units when comparing CES plus a standard treatment to a CES sham plus a standard treatment, and an effect size of 1.68 when comparing CES plus a standard treatment to standard treatments alone. The average effect sizes for the within groups studies were 0.534 SD units for CES treatments (P<.10), 0.391 SD units for CES sham treatment plus the standard treatment (P<..05) and, 0.171 SD units for the standard treatment alone. The range of the effect sizes for the within group studies were between 0.25 and 0.83 units. The authors concluded that the statistical significance of the within group analysis is quite impressive. To put this into perspective, the average effect size of all psychotherapies are between 0.70 and 0.80 SD units when compared to no treatment (roughly 75% of the pts who receive psychotherapy improve in their condition relative to controls who receive no therapy). The average effect size for non-specific factors or placebo effects among psychotherapies as compared to wait-list controls is about 0.40 SD units.
After achieving IRB approval and informed consent, 65 polysubstance abusers with no history of psychosis were recruited from the Oklahoma Department of Human Services and split into 3 groups for this double-blind study using blinding boxes. Pts were at a lock-in unit at the Chemical Dependency Unit. 36 subjects (18 CES, 16 controls, and 5 sham CES) left AMA. 20 males and 9 females from 20 to 49 years old (mean of 31.3) completed the full course of 45 minutes daily for 6 – 14 days. 9 pts in group 1 (31%) were non-CES controls receiving standard treatment, 9 pts (31%) in group 2 received simulated CES plus standard treatment, 11 pts (38%) received active CES plus standard treatment. The revised Beck Anxiety and Depression Inventories, and the Symptom Check List of the Himmelsbach Scale were administered, along with an attention placebo control interview, and observer-rated measures employed by 2 researchers: the Structured Interview Guide for the Hamilton Anxiety and Depression Scales. In order to achieve a power of .8 (beta = .2), alpha was calculated at .05, effect size at .60, and N at 30 (10 per group).
Scheffe tests were performed to determine the significance between the means of each of the 3 groups. There was no significant difference between variables at pretest. Analysis of variance (ANOVA) revealed significant post test group differences. Hamilton Anxiety means for CES pretest was 24.44 – 9.22 to a post test of 7.09 – 3.21, for sham CES pretest was 22.56 – 9.95 and post test was 15.67 – 7.92, and for controls pretest was 20.56 – 6.21 and posttest was 16.89 – 9.06. Scheffe post hoc tests for Hamilton was significant between the CES and controls (P<.05) and between the CES and sham (P<.05), but not the sham and control (P>.05) as measured by the observer ratings. Beck Anxiety post test means were not significant, means for CES pretest was 22.91 – 10.99 to a post test of 5.27 – 5.23, for sham CES pretest was 28.78 – 15.21 and post test was 9.33 – 7.97, and for controls pretest was 21.44 – 9.89 and posttest was 9.78 – 12.17. Although the self reports showed no statistical differences between groups, there was a trend towards significance. The study did not control for medications. The author concluded that the active CES, when combined with the normal treatment regimen given at the treatment facilities was more effective in reducing anxiety and depression than the normal treatment regimen alone and the sham CES plus normal treatment regimen. Thus, the anticipated results regarding CES was supported, while the anticipated results regarding placebo effect was not supported. No side effects were reported.