Transcranial Direct Current Stimulation (tDCS) in the Treatment of Drug-naïve Obsessive-compulsive Disorder(OCD)

Transcranial Direct Current Stimulation (tDCS) in the Treatment of Drug-naïve Obsessive-compulsive Disorder(OCD)

A Randomized Clinical Trial of Transcranial Direct Current Stimulation(tDCS) Treatment for Drug-naïve Obsessive-Compulsive Disorder(OCD)

This study will evaluate the possible therapeutic effects of Transcranial Direct Current Stimulation (tDCS) in drug-naïve obsessive-compulsive disorder (OCD) patients, and the underlying neural mechanism by magnetic resonance imaging (MRI),transcranial magnetic stimulation and electroencephalography (TMS-EEG).

The purpose of this study is to examine the efficacy of tDCS over orbitofrontal cortex (OFC) in treatment of drug-naïve OCD patients. 60 drug-naïve OCD patients will be randomized into two groups (i.e. active or sham stimulation). tDCS stimulation will be performed once a day, five times a week, for two weeks. The investigators will assess symptom severity before and after two weeks of tDCS. Through the study, Yale-Brown Obsessive Compulsive Scale（Y-BOCS）, the Obsessive Compulsive Inventory-Revised (OCI-R), the Beck Depression Inventory (BDI), the Beck Anxiety Inventory (BAI), Perceived Stress Scale (PSS), Pittsburgh sleep quality index (PSQI)and side-effect questionnaire will be obtained by a trained investigator. The patients will also receive MRI scan and TMS-EEG.

Cathode transcranial direct current stimulation over the right OFC will be applied once a day, 5 days a week, for 2 weeks.

The sham transcranial direct current stimulation over the right OFC will be applied once a day, 5 days a week, for 2 weeks.

The tDCS device will deliver a direct current of 1.5mA during 20 minutes. Cathode electrode will be localized in front of the right OFC on the Fp2 point according to the EEG international reference. Four anode electrodes will be placed around FP2 (i.e. Fpz, AFz, AF4, AF8)

The same procedure will be applied except that the tDCS device will only deliver a current stimulation for the first and last 15 seconds.

It assesses the severity of OCD symptoms. The Y-BOCS scale ranges from 0 to 40, with 0 being no symptoms and 40 being severe.The responder on Y-BOCS is defined as a Y-BOCS decrease at least 35% from the baseline at post-treatment.

It is an inventory of OCD symptoms with 18 items that are rated on a 5-point Likert scale. Total scores range from 0 to 72, with higher scores indicating more severe OCD symptoms.

It consists of 21 items and uses a 0 to 3 severity scale. Total scores range from 0 to 63, with higher scores indicating more severe depression symptoms.

It is an inventory of anxiety symptoms with 18 items that are rated on a 5-point Likert scale(0 to 4). Total scores range from 0 to 72, with higher scores indicating more severe anxiety symptoms.

It is a 10-item, 5-point Likert scale(0 to 4) to measure the degree to which situations in one's life are appraised as stressful.The total score ranges from 0 to 40, with lower total scores representing a better outcome.

The Pittsburgh Sleep Quality Index (PSQI) contains 19 self-rated questions which measures seven aspects of sleep: (1) subjective sleep quality, (2) sleep latency, (3) sleep duration, (4) habitual sleep efficiency, (5) sleep disturbances, (6) use of sleeping medication, and (7) daytime dysfunction. The 19 self-rated items are combined to form seven component scores, each of which has a range of 0-3 points (0 indicates no difficulty, while 3 indicates severe difficulty). The seven component scores are then summed to yield one global score, with a range of 0-21 points (0 indicating no difficulty, and 21 indicating severe difficulties in all the seven areas of sleep quality).

It consists of 10-item and uses 0 to 3 severity scale to rate the intensity of side effects. Total scores range from 0 to 30, with higher scores indicating more severe side-effect. It also assesses the relation between side-effect and the effects of tDCS using 0 to 4 scale. Total scores range from 0 to 40, with higher score indicating the greater relation.

Inclusion Criteria: age: 18-50 years old; DSM-5 criteria for OCD; Y-BOCS total score > or = 16, discontinued medication for at least 8 weeks before tDCS stimulation. >or＝9 years education Exclusion Criteria: Any axis I psychiatric disorder comorbidity The inability to receive tDCS because of metallic implants, or history of seizures，or 3.history of head injury, or history of neurosurgery. Participants with claustrophobic, heart pacemaker, mechanical heart valve, mechanical implant such as an aneurysm clip, hip replacement, or any other pieces of metal that have accidentally entered their body. Any current significant medical condition. serious suicide risk