tDCS for Increasing Exercise Adherence in Depressed Individuals

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to examine the efficacy of tDCS (transcranial direct current stimulation) for increasing exercise adherence among low active individuals with elevated depressive symptoms. The investigators expect that this project will contribute much needed knowledge about the role that tDCS can play in changing the affective experience of exercise.

Detailed Description
-----------------
Exercise adherence is a significant public health problem. Affective experiences during exercise predict long-term physical activity (PA) levels. Therefore, approaches to improving the affective experience of exercise are both important and likely to have high impact. This may be particularly true among individuals with elevated depressive symptoms due to their tendency toward more negative and less positive affect. tDCS is a noninvasive brain stimulation approach with a growing body of literature supporting its effects on cognitive and emotional processing in varied populations, including some support for those with depression. In addition, there is recent increased interest in utilizing tDCS in the context of exercise (see above) and in obesity prevention. While the effects of tDCS on behavioral and cognitive functioning are still developing, promising findings have emerged for tDCS used in repeated combination with a behavioral or cognitive intervention. Given that tDCS is relatively safe, inexpensive, and portable, individuals who struggle with enjoying exercise could be afforded a practical option for increasing and maintaining physical activity levels. We propose to conduct a pilot randomized controlled trial of tDCS versus sham delivered 3x/week for 8 weeks in the context of a supervised aerobic exercise (AE) program among 72 low-active individuals with elevated depressive symptoms. Follow-up assessments will be conducted at end of treatment, 3, and 6 months.

Official Title
-----------------
tDCS for Increasing Exercise Adherence in Individuals With Elevated Depressive Symptoms

Conditions
-----------------
Depression, Physical Activity

Intervention / Treatment
-----------------
* Other: tDCS
* Other: Sham tDCS
* Behavioral: Aerobic Exercise (AE)


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: be between 18 and 65 years of age be low active have elevated levels of depressive symptoms interested in starting an exercise program in the next month Exclusion Criteria: history of mania or hypomania current psychotic disorder current DSM-5 diagnosis of an eating disorder DSM-5 moderate and severe substance use disorder current suicidality or homicidality current DSM-5 diagnosis of major depressive disorder that is not currently being treated with pharmacotherapy or psychotherapy physical disabilities or medical problems that would prevent participation in moderate intensity exercise or may be contraindicated for tDCS current pregnancy or intent to become pregnant during the next 8 weeks pacemaker or metal implanted in the cranial cavity

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: tDCS and Aerobic Exercise<br>Each participant will undergo a 20-minute session of transcranial direct current stimulation (tDCS) delivered to the dorsolateral prefrontal cortex (DLPFC). Each session of tDCS will be immediately followed by a supervised 30-minute, moderate-intensity bout of exercise. These procedures will occur 3x/week for 8 weeks. | Other: tDCS<br>* Participants in transcranial direct current stimulation (tDCS) will receive tDCS over the dorsal-lateral prefrontal cortex for 20 minutes, 3 times per week for 8 weeks.<br>Behavioral: Aerobic Exercise (AE)<br>* Participants will engage in supervised, 30-minute bouts of moderate-intensity exercise 3x/week for 8 weeks.<br>|
| Sham Comparator: Sham tDCS and Aerobic Exercise<br>Each participant will undergo a 20-minute session of sham transcranial direct current stimulation (tDCS) delivered to the dorsolateral prefrontal cortex (DLPFC). Each session of tDCS will be immediately followed by a supervised 30-minute, moderate-intensity bout of exercise. These procedures will occur 3x/week for 8 weeks. | Other: Sham tDCS<br>* Participants in sham transcranial direct current stimulation (tDCS) will receive shame tDCS over the dorsal-lateral prefrontal cortex for 20 minutes, 3 times per week for 8 weeks.<br>Behavioral: Aerobic Exercise (AE)<br>* Participants will engage in supervised, 30-minute bouts of moderate-intensity exercise 3x/week for 8 weeks.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Physical Activity Levels | Accelerometry-based moderate-to-vigorous physical activity (MVPA) | 8 week assessment |