To investigate the intervention effect of high definition transcranial direct current stimulation (HD-tDCS) assisted Electroconvulsive Therapy (ECT) for depressive disorder.

Depression is a mental disorder characterized by low mood, decreased interest, and reduced activity. It affects approximately 350 million people around the world and has become a major public health and social problem. Electroconvulsive therapy (ECT) can quickly and effectively improve depressive symptoms, but it causes severe impairment of cognitive functions, such as reduced face memory. Therefore, improving treatment options is of great significance.

Electroconvulsive therapy depends on the number of treatments, usually 2-3 times a week, for a total of 6-12 treatments. Studies have shown early mood improvement after the third ECT. The investigators propose a new ECT treatment strategy, which involves sequential hybridization of high definition transcranial direct current stimulation (HD-tDCS) after the third ECT to maintain its efficacy while mitigating cognitive side effects.

60 patients with depressive disorder diagnosed by Diagnostic and Statistical Manual of Mental Disorders(DSM-5) were recruited from the fourth people's Hospital of Hefei and the Second Hospital of Anhui Medical University. All participants underwent a structured interview and routine laboratory examination before treatments. After meeting the inclusion criteria and obtaining informed consent, All the participants were randomized (1:1:1) into three groups: ECT combined with real stimulation tDCS group, ECT combined with sham stimulation tDCS group, and ECT full course group.

For ECT combined with real stimulation tDCS group, Bifrontal short-pulse ECT was performed once a day for 3 consecutive days. Then,tDCS stimulates the dorsomedial prefrontal cortex. The anode was placed over Fz with return electrodes placed at Fpz, Cz, F3 and F4. 2 milliampere(mA) (ramp-up and ramp-down periods of 30 and 30 seconds, respectively) were applied for 20 minutes Twice a day over 10 consecutive sessions.

For ECT combined with sham stimulation tDCS group,Bifrontal short-pulse ECT was performed once a day for 3 consecutive days.Then,Sham HD-tDCS was delivered using the same protocol and current intensity, but the period of active stimulation was only during the ramp-up and ramp-down periods of 30 and 30 seconds.

For ECT full course group,Bifrontal short-pulse ECT was performed once a day for 3 consecutive days, then once every other day, for a total of 6 times,as a traditional contrast Emotional and memory function assessments were conducted at three time points: baseline, post-ECT, and post-TDCS. Emotional assessments included Hamilton Rating Scale for Depression(HAMD), Hamilton Anxiety Scale(HAMA), Beck Scale For Suicide Ideation(BSS), Patient Health Questionnaire-15(PHQ15), Ruminative Responses Scale(RRS), The Temporal Experience of Pleasure Scale (TEPS) and The Positive and Negative Affect Scale(PANAS). Memory function assessments included association memory and working memory.

Inclusion Criteria:

• the patients were diagnosed by more than 2 psychiatrists and met the diagnostic criteria of DSM-5 for depression, and HAMD>17.
• Meets the ECT treatment indication
• the age ranged from 18 to 60 years old, and the length of education was more than 5 years.
• the visual acuity or corrected visual acuity is normal, right-handed, can cooperate with the completion of various experimental tests.

Exclusion Criteria:

• accompanied by severe somatic diseases, such as severe heart, liver, renal insufficiency and so on.
• accompanied by other neurological diseases, such as stroke, epilepsy and so on. pregnant and lactating women.
• accompanied by other mental disorders, such as drug abuse, schizophrenia, schizophrenic affective disorder, hysteria, autism and so on.
• with a history of ECT treatment within the past 3 months