This study utilized a 6-week open-label design to test CES in the treatment of GAD. The study was funded by Saban Family foundation. The devises were provided by Electromedical Products Inc. (EPI) which is a technology company manufacturing the cranial stimulators. This company has no relationship with any of the investigators of the study. There are no explicit or implicit conflicts of interest. Participants were recruited from August 2005 to March 2006 from the UCLA Anxiety Disorders Program at the Semel Institute for Human Behavior. Permission from UCLA's Institutional Review Board was obtained to conduct this study. All eligible subjects provided approved written consent prior to the initiation of any study related procedure.

Patient Selection: Male or female outpatients aged 18 to 64 years were eligible if they had a current diagnosis of GAD. At screening, GAD diagnosis was confirmed by conducting the MINI interview.(Sheehan, Lecrubier et al. 1998) Patients had to have a score ≥ 16 on the Hamilton Anxiety Rating Scale (HARS) and \< 17 on the 17-Item Hamilton Depression Rating Scale (HDRS) at baseline to be considered for enrollment.(Hamilton 1959; Hamilton 1960) Lower then usual HARS were permitted to include milder cases of GAD. Patients were excluded if they had a primary diagnosis meeting DSM-IV criteria for any other Axis I disorder other than GAD, as were patients who met DSM-IV criteria for mental retardation, any pervasive developmental disorder or neurological impairment. Also excluded were those with a recent (6 months) history or current diagnosis of drug or alcohol dependence or abuse, current suicidal ideation and/or history of suicide attempt or any personality disorder of sufficient severity to interfere with participation in the study. Other exclusion criteria included a history or presence of a medical disease that might compromise the study or be detrimental to the patient. Women who were pregnant or breastfeeding and women of childbearing potential who were not practicing a reliable form of contraception were also excluded from the study and the use of any psychotropic medication. Patients were permitted to be on a stable, therapeutic dose of SSRI or SNRI if they were taking their medications for at least 3 month and were still symptomatic after at least 3 months of treatment. Patients who used PRN as-needed benzodiazepines were permitted to enter the study if their use of the medications did not exceed two times per week. Women who were pregnant or breastfeeding and women of childbearing potential who were not practicing a reliable form of contraception were also excluded from the study. Study visits were conducted at baseline and at the end of 3 and 6 weeks of treatment. Patients who met all of the eligibility criteria at baseline were enrolled and administered CES treatment.

Results: Fifteen subjects expressed interest in the study and engaged in an initial telephone screen. Eight percent (n=3) of participants were deemed ineligible to participate. Reasons for ineligibility included age (n=1; 3%) and psychiatric co morbidity (n=2; 6%). Twelve subjects enrolled and received CES treatment. The mean age of the sample was 42.83±10.7 years. Of the twelve individuals enrolled in the study 9 (75%) were female and 3 (25%) were male. Five participants (41.6%) had been taking psychotropic medications for at least 3 months prior to enrollment and continued throughout the study; two participants took venlaflaxine and the remaining 3 patients took benzodiazepines on an as-needed basis no more than twice a week (2 took alprazolam, and 1 took lorazepam). Overall, 75% of patients (n=9) completed the study. Three subjects discontinued after baseline due to adverse events, including dizziness (n=2) and headache (n=1). A significant change (11.5 points) was found from baseline to endpoint in HARS scores (t= 8.59 p= 0.001). The mean change from baseline was significant after 2 weeks of treatment and continued to increase over time. At endpoint, 6 (66%) of 9 patients had a 50% decrease on HARS and a score of 1 or 2 on CGI improvement, and were considered responders to treatment. An additional patient improved but did not meet criteria for response. Mean HDRS score changed from 10.5±15.01 at baseline to 6±3.64 at endpoint (t= 3.01, p=0.01). A significant change was also found from baseline (30.3±11.49) to endpoint (23.3±6.76) in UCLA 4D Anxiety Subscale scores (t=2.63, p= 0.03).

Results of the current study demonstrate a significant improvement with CES, with a decrease in HARS score similar to that found in clinical trials with antidepressant and anxiolytic medications .(Katz, Reynolds et al. 2002; Rickels and Rynn 2002; Pollack, Meoni et al. 2003; Sheehan and Mao 2003; Bielski, Bose et al. 2005; Brawman-Mintzer, Knapp et al. 2006; Dhillon, Scott et al. 2006). The effect size is 2.4 appears to be very large. However, it is expected in an open trial where some part of the parts of the effect could be due to placebo response. The above cited studies had an effect size for placebo ranging from 0.74 to approximately 1.72. Most of the recent pharmacological studies in GAD observed a large placebo response which makes it imperative to conduct placebo-controlled or sham-controlled study to fully evaluate the treatment effect in this population (Rickels and Rynn 2002)

The patients generally liked the treatment and 3 of them continued to use the devise after the experiment was over and purchased their own CES stimulator. However, 3 of the subject experience the side effects which caused them to withdraw prematurely from the study. Presence of side effects in some of the patients could be the sign of some physiological effect in these patients which needs to be studied in future studies.