A Summary Look at CES Studies Of Anxiety

By Ray B. Smith, Ph.D.

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Executive Summary

Thirty-eight studies were analyzed, in which a total of 1,495 patients were treated with cranial electrotherapy stimulation (CES) for anxiety. The patients had presented with various clinical syndromes, of which anxiety played a major part. The treatment outcome anxiety scores were combined statistically in order to get a more confident look at the effectiveness of CES for treating this condition. While the majority of the studies were of the classic double blind protocol, others used either the single blind, the cross over design or were open clinical trials. The result of the analysis showed that the overall effectiveness of CES was an impressive 58% improvement. The results indicated that various types of anxiety, which accompany a wide range of clinical syndromes can be expected to respond, sometimes dramatically to CES treatment.

Introduction

Meta-analysis is a way of combining the results of many separate studies to see the effectiveness of a treatment when different types of patients are studied, under different study conditions, with different study protocols, and who came to the various studies with differing symptoms accompanying their sleep problem.

The goal of clinical studies is always to first test the effectiveness of a potential treatment and secondly to discover which patients the treatment may be most effective in treating. Meta-analysis has the effect of allowing one to essentially study a larger number of patients than can usually be assembled for a single study, and the larger the combined study sample, the greater is the confidence that can be placed in the study outcome: that the study findings are true and accurate. Also, the more diverse the study group is in the combined sample, the more confident one can be in generalizing the study outcome to larger groups of patients outside the study. That is, it increases the range of potential types of anxiety patients that one can predict will be effectively treated with CES.

In the table below is a summary of 38 studies that were combined into the meta-analysis reported on here.

CES Anxiety Studies Completed Over the Past 36 Years


Study Design

Zr Scorea

Presenting
Group

No. Subjects

Measure Usedb

Reference

Double Blind

.950

Substance Abuse

47

Clinical Rating Scales

1

Double Blind

.412

Outpatient Psychiatric
Abuse

32

Self Rating Scale

2

Double Blind

.365

Substance Abuse

28

Self Rating Scale

3

Double Blind

.549

Outpatient Psychiatric

28

Clinical Rating Scale

4

Double Blind

.720

Outpatient Pain Patients

20

Physiological Measures

5

Double Blind

.604

Outpatient Pain Patients

30

Physiological Measures

6

Double Blind

.563

Psychiatric Prisoners

28

Clinical Rating Scale

7

Double Blind

.625

Substance Abuse

20

Self Rating Scales

8

Double Blind

1.099

Psychiatric Inpatients

11

Self Rating Scale

9

Double Blind

.233

Psychiatric Inpatients

60

Self Rating Scales

10

Double Blind

.693

Substance Abuse

21

Self Rating Scale

11

Double Blind

.775

Psychiatric Inpatients

24

Self Rating Scale

12

Double Blind

.618

Psychiatric Inpatients

20

Self Rating Scale

13

Double Blind

.405

Psychiatric Outpatients

80

Clinical Rating Scales

14

Double Blind

.365

Substance Abuse

60

Self Rating Scales

15

Double Blind

.693

Closed Head Injured

21

Self Rating Scale

16

Double Blind

.549

Normal Volunteers

30

Physiological Measures

17

Double Blind

.567

Prison Sex Offenders

105

Self Rating Scale, Physiological Measures

18

Double Blind

.618

Substance Abuse

24

Self Rating Scale

19

Double Blind

.633

Dental Patients

33

Self and Clinician Rating Scales

20

Double Blind

.811

Psychiatric Outpatients

22

Clinical Rating

21

Totals

12.847

 

744

 

 

Average

.612

 

 

 

 

Effect Sizec

r = .55

 

 

 

 

Single Blind

.497

Substance Abuse

72

Clinical Rating Scales

22

Totals

.497

 

72

 

 

Average

.497

 

 

 

 

Effect Size

r =.46

 

 

 

 

Crossover

.321

Psychiatric Inpatients

23

Clinician’s Rating

23

Crossover

.080

Insomnia, Anxiety

28

Clinician’s Rating

24

Crossover

.365

Outpatient Psychiatry

17

Clinician’s Rating

25

Crossover

1.757

Outpatient Psychiatry

10

Self, Clinicin’s Ratings

26

Totals

2.523

 

78

 

 

Average

.631

 

 

 

 

Effect Size

r =.56

 

 

 

 

Open Clinical

.563

Psychiatric Outpatients

25

Clinician’s Rating

27

Open Clinical

.523

Psychiatric Outpatients

12

Clinician’s Rating, Physiological Measure

28

Open Clinical

.973

Psychiatric Inpatients

20

Clinician’s Rating

29

Open Clinical

.621

Graduate Students

54

Self Rating Scales

30

Open Clinical

.640

Psychiatric Outpatients

182

Physiological Measures

31

Open Clinical

1.344

Substance Abuse

32

Self Rating Scale, Physiological Measure

32

Open Clinical

.973

Substance Abuse

186

Clinician’s Rating

33

Open Clinical

.510

Psychiatric Outpatients

9

Clinician’s Rating

34

Open Clinical

604

Psychiatric Outpatients

12

Clinician’s Rating

35

Open Clinical

1.039

Psychiatric Outpatients

23

Self Rating Scales

36

Open Clinical

.436

Phobic Outpatients

31

Self Rating Scale

37

Open Clinical

1.099

Prison, Sex Offenders

15

Self Rating Scale

38

Totals

9.325

 

601

 

 

Average

.777

 

 

 

 

Effect Size

r =.65

 

 

 

 

SUMMARY, ALL ANXIETY STUDIES REPORTED ABOVE

Grand Total

25.192

 

1,495

 

 

Average

.663

 

 

 

 

Total Effect Size

r =.58

 

 

 

 

a r correlation scores, representing percent improvement, are obtained mathematically from the study outcomes presented by the authors. Scores such as percent change scores, statistical probability scores, F scores, t scores, and the like, are changed to r correlation scores and then into Zr scores. That is because percent improvement scores can not legally be averaged. The Zr scores are then averaged and converted back to percent improvement (effect size.)

b Most of the rating scales, both by the patients and the clinicians were of published reliability and validity. In many of the studies, more than one measure of anxiety was used. In those cases, the average of the results was calculated and reported as the overall result of the study.

c Effect size, here, is a statistician’s basic estimate of the overall percentage improvement by the patients as a result of the treatment.

Discussion

In many of the studies, anxiety was but one symptom within a larger presenting syndrome. For example in many of the patients, fibromyalgia was the presenting symptom, while in another large group of studies the substance abuse (drug abstinence) syndrome was the presenting diagnosis. The presenting syndrome or type of patient is given in column three of the table. In all of the studies, however, anxiety was a major diagnosis within the presenting syndrome or group.

A word about the study types. In the open clinical study, the patients know they are being actively treated for their anxiety, the clinicians know who is being treated, and the statistician who summarizes the study data also knows, since there is only one group of patients.

In the single blind study, the patients do not know which are getting treated and which are getting sham treatment, but the clinician providing the treatment knows which are the treated patients. In the single blind study, the clinician doing the post study evaluation of the patients is often blinded to treatment conditions when he completes his evaluation. The statistician is usually blinded also, so that he is given two sets of scores to compare, and doesn’t know which group received the treatment. This study design was used earlier on before treatment blinding devices came on stream. In such studies, the treatment was administered sub sensation threshold, in which the clinician turned up the current intensity until the patient just felt it, then turned it back down until the patient said he could no longer feel the stimulation. At that point, the clinician either left the current at that level or turned the unit off (down to, but not including the final click). Because both the patients and the statistician are both blind to the study conditions, some authors have unwittingly published this design as a double blind experiment. But that term is generally reserved for the true double blind experimental design as described next.

The double blind study, the gold standard of science, is usually confined to studies in which neither the patient or the clinician knows who is being studied. Those designs became available when a double blinding box could be inserted between the patient and the CES device. The double blinding box often had three, four or more settings in addition to a “0” setting in which current flowed freely between the CES unit and the patient. Among the other settings available, some passed current to the patient and some blocked it entirely. The clinician would begin the double blind treatment session by setting all double blinding boxes to the “0” position, would connect the patient to the CES electrodes, turn the current up slowly until the patient signaled he could just feel it, then reduce the stimulus level until the patient signaled that he could no longer feel it. At that point, the clinician set the double blinding box to one of the other settings available and left the patient on the device for 30 minutes to an hour, not knowing who was getting active treatment.

Interestingly, in a good double blind experimental design, such as was the case in the majority of those reported in the table, the persons who were responsible for measuring or rating patient improvement were also blind as to who was treated, as was the statistician who was given anonymous groups of data to analyze. Note that, in effect, that makes such studies quadruple blind, but that term is not used in science.

In the crossover design, half the patients get treated the first week or two of the study, while the other half receive sham treatment. In the second half of the study, the formerly treated patients now receive sham treatment while the formerly sham treated patients now receive treatment. If the crossover does not involve a sham treatment condition, then the crossover study is treated as an open clinical trial where all patients and staff know who is being treated at each cross of the study. That design is often referred to as a study with “wait in line” controls, in that the patients waiting to begin treatment are tested before and at the end of the waiting period before going into treatment. That is thought to control for environmental factors such as unusual stressors on the 10 O’clock news, any local dramatic weather changes, and so forth.

Interestingly we learned early on in CES work to stay clear of the cross over design in CES studies, after we discovered that the improvement begun by a week or so of CES treatment often continues after treatment is stopped. That is, the patients continue to get better as time goes on following treatment. One can imagine what that does to the statistical analysis when at the end of the study, both groups have improved significantly, but the patients treated first are no longer behaving as good controls should, but are getting even better than the final treatment group is showing. Many otherwise good studies were lost early on due to that effect. It is interesting, for example that the study that obtained by far the worst apparent improvement among the 38 studies was a crossover study.

Safety

It is interesting to note that not one problem from negative side effects has ever been found in any published CES anxiety study. None of the patients has threatened or attempted suicide during or following treatment. None has complained of grogginess the next day. None has complained of headaches or a foggy feeling following treatment. When asked, CES patients have reported instead feeling more rested, more alert, and less tired following treatment.

One interesting clinical detail we learned early on is that patients who have not been sleeping well when they enter a study sometimes make up for lost REM sleep during CES treatment and have the most vivid, most colorful dreams they have ever had. We learned to warn study participants of this in advance, since some earlier patients associated this with incipient schizophrenia or some other serious mental condition. Once alerted to the possibility they have always looked forward to the effect with real anticipation.

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