The Effect of Transcranial Direct Current Stimulation on Decision Making and Cognitive Flexibility in Gambling Disorder

The investigators conducted a double-blind randomised sham-controlled study. Upon enrollment into the study, participants were randomly assigned to one of two conditions: (i) active group: anodal stimulation over the right dlPFC (n = 10) or (ii) sham stimulation group (n = 10). Participants and raters were blinded to the condition.

Subsequently, the participants were administered the IGT and the Wisconsin Card Sorting Test by a trained neuropsychologist in a quiet laboratory. A computerized version of standard IGT was used. The order of the tasks performed in a single session was randomised.

After the psychiatric and neurocognitive assessment, participants received three sessions of 20-minute active or sham anodal tDCS (once a day, every other day).

Wisconsin Card Sorting Test and a modified version of Iowa Gambling Test were readministered after the last application. The order of the tasks was randomized again. A brief questionnaire on study blinding was also administered. Safety was assessed through open-ended questions based on the tDCS adverse events questionnaire

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Key information

Conditions

Gambling Disorder Behavior Disruptive, Impulse Control, and Conduct Disorders Gambling Mental Disorders Risk-Taking

Age range

18 year–65 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 3

Primary location

Ahmet Zihni Soyata

Istanbul, 34093, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Participants meeting Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for gambling disorder
Being right-handed
Being 18-65 years old
Being drug-free

Exclusion criteria

Current DSM-5 diagnosis of major depressive disorder
Current or previous DSM-5 diagnosis of alcohol and substance use disorders, schizophrenia, bipolar disorder, or other psychotic disorder
Drug Use in the past 4 weeks of any medication with known pro-convulsant action or current regular use of any psychotropic medications (benzodiazepines, antipsychotic medications, tricyclic antidepressants, anti-epileptics, mood stabilizers)
Any history of any clinically significant neurological disorder, including organic brain disease, epilepsy, stroke, brain lesions, multiple sclerosis, previous neurosurgery, or personal history of head trauma that resulted in loss of consciousness for > 5 minutes and retrograde amnesia for > 30 minutes,
The presence of mental retardation diagnosis (previously identified)
Any personal or family history (1st degree relatives) of seizures other than febrile childhood seizures
Illiteracy, deficient language or refusal to participate.

Treatment and study plan

Transcranial Direct Current Stimulation

Device

Transcranial direct current stimulation (tDCS) is a safe method for non-invasively modulating cortical excitability through the use of weak electrical currents (usually of 1-2 mA) circulating between two scalp electrodes (i.e., an anode and a cathode) placed over the target cortical regions. The effects of tDCS on brain activity are polarity-dependent, such that anodal stimulation generally enhances cortical excitability by depolarizing cell membranes and increasing neuronal firing rates, while cathodal stimulation generally results in the opposite effect. Because of its neural effects, tDCS has been increasingly used to gauge the functional relationship between cognitive/behavioural dimensions and putatively relevant neurocircuitry

Primary outcomes

Changes in the Iowa Gambling Task net score

Time frame: Baseline, after tDCS treatment

Iowa Gambling Task net score is the total score of the task (between -100 and 100) that generally assesses the decision making under ambiguity, but also assesses the decision making under risk at the later stages. Higher scores in the task represents better decision making and healthy people generally have scores above 8-10 in the task.
Changes in the number of perseverative errors in Wisconsin Card Sorting Task

Time frame: Baseline, after tDCS treatment

Wisconsin Card Sorting Task is the widely used task to assess frontal lobe functions such as cognitive flexibility, set shifting and abstraction abilities. The participants were required to match response cards to 4 stimulus cards along 1 of 3 dimensions (colour, form or number) on the basis of verbal feedback (correct or incorrect). The participants were not given any information about the dimensions. After sorting a series of 10 cards in 1 category, participants were asked to sort the cards in a different category. The number of perseverative errors in Wisconsin Card Sorting Task is the most robust variable of the task to assess cognitive flexibility. Higher scores show an impairment of cognitive flexibility

Sponsors and collaborators

Lead sponsor

Istanbul University

Other

Registry information

Important dates

Study start: 2017
Primary completion: 2017
Study completion: 2017
First posted: Mar 26, 2018
Registry last updated: Mar 26, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed