An interventional study of Transcranial Alternating Current Stimulation Sham and Transcranial Alternating Current Delta Stimulation. in Cannabis Use Disorder, Major Depression and Anhedonia, sponsored by Florida State University. Recruiting at 2 sites in United States. Open to participants aged 18 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by Florida State University · Not applicable, Interventional, and Basic science
Cannabis use disorder (CUD) and major depressive disorder (MDD) are among the most prevalent psychiatric conditions in the United States, affecting an estimated 20.6 million and 21 million adults respectively. Both disorders are characterized by anhedonia, diminished motivation, and blunted neural reward sensitivity. This shared dysregulated reward-processing may reflect a common prefrontal oscillatory dysfunction, centralized in mesolimbic dopaminergic reward pathways. This proposed project aims to investigate if transcranial alternating current (tACS) can modulate motivational behaviours and neural reward responsivity in participants with MDD and/or CUD during an effortful reward task. The investigators hypothesize that delta transcranial alternating current stimulation will produce a greater neural reward responsivity (RewP), and motivational behaviour during an effortful reward task.
Disrupted reward processing is a transdiagnostic feature that plays a central role in the development, and maintenance of anhedonia in Cannabis Use Disorder (CUD) and Major Depressive Disorder (MDD). Reward positivity (RewP) is an event-related potential (ERP) component derived from electroencephalogram (EEG) data, associated with motivation, reward responsivity and valuation. This neural signature originates in the medial and dorsolateral prefrontal cortexes. In MDD, reduced RewP has been associated with decreased willingness to expend effort for reward. Research of CUD and RewP is scarce, but dampened RewP has been demonstrated across different substances use disorders (SUDs) in response to monetary reward tasks. Taken together, these findings signal an emerging research frontier to establish RewP as a clinical biomarker and create a compelling mandate for causal investigation. Low-frequency neural oscillations are the key mechanisms facilitating long-distance prefrontal connectivity and interregional communication. Delta oscillations (2.5Hz) in medial and left lateral prefrontal cortexes are closely linked to RewP and reward prediction error signaling, while theta oscillations (6Hz) index cognitive control and prefrontal regulatory engagement during reward processing. Disruptions in both bands have been well documented in MDD, to a more limited extent, in cannabis-using populations. The proposed experiment will causally test whether sham, delta, and theta frequency tACS can alter motivation and reward responsivity (behaviourally [Effort behaviour] and neurally [RewP, delta power]), in participants with disorder of reward dysfunction, CUD, MDD, and healthy controls. Findings from the proposed study will aid in mechanistic understanding of prefrontal circuits underlying reward impairment in CUD and MDD, and ultimately enable for the development of novel brain stimulation techniques to target disorder-maintaining anhedonia. The investigators hypothesise that delta tACS will modulate reward responsivity in participants with disorders of reward. Such that, during the EEfRT Task delta stimulation will enhance reward responsive goal directed behaviour (Behavioral H1) and delta phase connectivity between left lateral and medial frontal electrodes (Neural H1) at effort decision period. As well as greater reward positivity (RewP; Neural 2), and win vs. loss delta power and phase coherence at feedback (Neural H3).
3,041 studies on the registry are indexed under Depressive Disorder, Major; 588 are open to participants now.
This study's planned enrollment of 54 is below the median of 79 across 2,530 interventional studies indexed under Depressive Disorder, Major.
Browse Depressive Disorder, Major studies →Florida State University is the lead sponsor of 249 studies on the registry; 47 are open to participants now.
Of its 16 completed or terminated interventional studies of FDA-regulated products, 9 (56%) have results posted.
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Exclusion Criteria (General):
Specific CUD Inclusion:
Specific MDD Inclusion:
Specific Control Inclusion:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants receive delta (2.5 Hz), theta (6 Hz), and sham tACS across three separate sessions, separated by a 7-10 day washout. Session order is randomised and counterbalanced using a balanced Latin square, within each diagnostic group (CUD, MDD, healthy control). Stimulation is interleaved between the 8 blocks of the EEfRT (e.g., block 1 with stimulation, block 2 without, etc.). EEG activity will be recorded throughout the non-stimulation 4 blocks and proceeding interleaved non-stimulation blocks.
Device: Transcranial Alternating Current Delta Stimulation.
All participants receive delta (2.5 Hz), theta (6 Hz), and sham tACS across three separate sessions, separated by a 7-10 day washout. Session order is randomised and counterbalanced using a balanced Latin square, within each diagnostic group (CUD, MDD, healthy control). Stimulation is interleaved between the 8 blocks of the EEfRT (e.g., block 1 with stimulation, block 2 without, etc.). EEG activity will be recorded throughout the non-stimulation 4 blocks and proceeding interleaved non-stimulation blocks.
Device: Transcranial Alternating Current Theta Stimulation
All participants receive delta (2.5 Hz), theta (6 Hz), and sham tACS across three separate sessions, separated by a 7-10 day washout. Session order is randomised and counterbalanced using a balanced Latin square, within each diagnostic group (CUD, MDD, healthy control). Stimulation is interleaved between the 8 blocks of the EEfRT (e.g., block 1 with stimulation, block 2 without, etc.). EEG activity will be recorded throughout the non-stimulation 4 blocks and proceeding interleaved non-stimulation blocks.
Device: Transcranial Alternating Current Stimulation Sham
The tACS stimulation is briefly turned on and off over the course of 15-30 seconds.
Approximately 20-minutes of delta stimulation (2.5Hz) applied to F3 (returns AF7, FC5, FC1) and AFz (returns Fp1, Fp2, F2). Transcranial Alternating Current Stimulation Device is NeuroConn DC-Stimulator MC.
Approximately 20-minutes of theta stimulation (6Hz) applied to F3 (returns AF7, FC5, FC1) and AFz (returns Fp1, Fp2, F2). Transcranial Alternating Current Stimulation Device is NeuroConn DC-Stimulator MC.
Effort-updating behavior during decision period.
The % of hard effort choices selected following a win versus following a loss.
Time frame: Baseline (Day 0), Sham Session (Day 1-10, or Day 10-20, or Day 20-30), Theta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30), Delta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30). Specific range depends on particular counterbalanced order.
Delta phase coherence between left lateral and medial frontal electrodes during decision period following a win versus following a loss.
Electrical activity of the brain will be recorded via EEG during performance of the task and neurostimulation. Delta phase connectivity between left lateral and medial frontal electrodes during the decision period following a win versus following a loss.
Time frame: Baseline (Day 0), Sham Session (Day 1-10, or Day 10-20, or Day 20-30), Theta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30), Delta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30). Specific range depends on particular counterbalanced order.
Reward positivity amplitude
Electrical activity of the brain will be recorded via EEG during performance of the task and neurostimulation. Reward positivity amplitude to wins vs. losses.
Time frame: Baseline (Day 0), Sham Session (Day 1-10, or Day 10-20, or Day 20-30), Theta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30), Delta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30). Specific range depends on particular counterbalanced order.
Delta event-related spectral power
Electrical activity of the brain will be recorded via EEG during performance of the task and neurostimulation. Delta power to wins vs. losses.
Time frame: Baseline (Day 0), Sham Session (Day 1-10, or Day 10-20, or Day 20-30), Theta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30), Delta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30). Specific range depends on particular counterbalanced order.
Delta intertrial phase coherence
Electrical activity of the brain will be recorded via EEG during performance of the task and neurostimulation. Delta intertrial phase coherence to wins vs. losses.
Time frame: Baseline (Day 0), Sham Session (Day 1-10, or Day 10-20, or Day 20-30), Theta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30), Delta Stim. Session (Day 1-10, or Day 10-20, or Day 20-30). Specific range depends on particular counterbalanced order.
Plan to share: No — The IPD will only be shared under reasonable request. The investigators might not share IPD in order to keep participant confidentiality paramount.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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