Developing Alternative Treatments for Young People with Depression: A study of transcranial alternating current stimulation (tACS).

Intervention

Intervention code Treatment: Devices

tACS treatment frequency will be determined during an EEG recording (see EEG assessment section below for details on EEG recording equipment). During the EEG recording, the N-back working memory task will be administered to participants to elicit theta oscillations, and the Sternberg working memory task will be administered to elicit alpha oscillations. Stimulation frequency will then be set to each individual’s theta and alpha frequency measurements, depending on the treatment allocated. The cu .... tACS treatment frequency will be determined during an EEG recording (see EEG assessment section below for details on EEG recording equipment). During the EEG recording, the N-back working memory task will be administered to participants to elicit theta oscillations, and the Sternberg working memory task will be administered to elicit alpha oscillations. Stimulation frequency will then be set to each individual’s theta and alpha frequency measurements, depending on the treatment allocated. The current of tACS delivered 48,000 cycles (i.e. 20 mins) with no DC current offset. The current ramps gently over a period of e.g. 5-10 seconds to the desired peak for patient comfort. The stimulator fade in and fade out was specified to 100 cycles at the beginning and end of stimulation. A pair of 5x5cm electrodes placed within saline soaked sponges and a purpose-built battery-driven constant stimulator will deliver the current. The electrodes will be placed over the left pre-frontal cortex on F5 and, over the right pre-frontal cortex on F6, located using the 10-20 EEG position. This electrode montage has been modelled to show a reasonably widespread current flow through fronto-central cortical and frontal subcortical regions. tACS treatment course: The tACS course is a 4 week program that has two phases. A ‘lead in/out’ phase that happens at week 1 and week 4 and an intensive phase that happens during week 2 and week 3. • Week 1 and week 4 – one 20 minute session of tACS per day for 5 days a week (Monday to Friday) • Week 2 and week 3 – two 20 minute sessions of tACS per day with at least 4 hours break between sessions, for 5 days a week (Monday to Friday).
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Comparison

Control group Placebo

Sham protocol: Sham stimulation is achieved by applying a period of 2 minutes of tACS at 13 Hz (i.e. a low beta frequency) with a 10 second ramp on and 10 second ramp off to provide the participant an experience of stimulation. The switching off of the stimulation pre-programmed within the software of the device. The participant will just turn the device on for 20 minutes without any indication of the type of stimulation. There is no evidence that the brief 120 second period of stimulation produ .... Sham protocol: Sham stimulation is achieved by applying a period of 2 minutes of tACS at 13 Hz (i.e. a low beta frequency) with a 10 second ramp on and 10 second ramp off to provide the participant an experience of stimulation. The switching off of the stimulation pre-programmed within the software of the device. The participant will just turn the device on for 20 minutes without any indication of the type of stimulation. There is no evidence that the brief 120 second period of stimulation produces lasting biological effects.
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Outcomes

Outcome: Changes in severity of depressive symptoms as measured by change in Montgomery-Asberg Depression Rating Scale (MADRS) scores.
Timepoint: Baseline, 4 weeks (end-point)

Outcome: Changes in severity of depressive symptoms as measured by change in Beck Depression Inventory (BDI) scores.
Timepoint: Baseline, 4 weeks (end-point)

Outcome: Changes in severity of depressive symptoms as measured by change in Five Facet Mindfulness Questionnaire (FFMQ) scores.
Timepoint: Baseline, 4 weeks (end-point)