HAMA is a 14-item test measuring the severity of anxiety symptoms. The total anxiety score ranges from zero to 56, with higher scores indicating more anxiety. The seven psychic anxiety items elicit a psychic anxiety score that ranges from 0 to 28. The remaining seven items yield a somatic anxiety score ranging from 0 to 28.

HAMD-17 ranges from 0 to 52, with higher scores indicating more depression; a score of 20 or more indicates moderate to severe depression.

PSQI is a 19 items measurement of several aspects of sleep, offering seven component scores and one composite score. The component scores consist of subjective sleep quality, sleep latency (i.e., how long it takes to fall asleep), sleep duration, habitual sleep efficiency (i.e., the percentage of time in bed that one is asleep), sleep disturbances, use of sleeping medication, and daytime dysfunction.

Each item is weighted on a 0-3 interval scale. The global PSQI score is then calculated by totaling the seven component scores, providing an overall score ranging from 0 to 21, where lower scores denote a healthier sleep quality.

The Clinical Global Impression-Severity scale (CGI-S) is a 7-point scale that requires the clinician to rate the severity of the patient's illness at the time of assessment. Score 1 presents normal, not at all ill, and score 7 presents among the most extremely ill patients.

The Clinical Global Impression-Improvement scale (CGI-I) is a 7-point scale that requires the clinician to assess how much the patient's illness has improved or worsened relative to a baseline state at the beginning of the intervention. Score 1 presents the patient as much improved, and score 7 presents much worse.

EQ-5D-5L is an instrument that evaluates the generic quality of life. The descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems, and extreme problems. The score ranges from 5 (having no problems) to 25 (being unable to do/having extreme problems).

This scale has 11 items and is based on the patient's subjective report of his or her clinical condition over the previous 48 hours. There are four items that are graded on a 0 to 8 scale (irritability, speech, thought content, and disruptive/aggressive behavior), while the remaining seven items are graded on a 0 to 4 scale. Scores range from 0 to 60, with higher scores indicating more severe mania. A score of 0 to 5 means no obvious manic symptoms; a score of 6 to 10 means definite manic symptoms; a score of 22 or above means severe manic symptoms. It will be used as a systematic screen for DBS-induced mania or hypomania. Although scores above 8 have been considered evidence of manic symptomatology in bipolar patients, the unmasked physician will use this scale and screening questions to assess whether any hypomanic symptoms require clinical intervention including DBS adjustment.

Possible Adverse Events include:

Major and minor adverse events will be evaluated by Adverse Events Questionnaire (AEQ) and accompanying Case Report Form (AEQ CRF) in multiple domains, including psychiatric, neurological, and cognitive effects. The AEQ includes cognitive and behavioral screening items used in the Xuanwu DBS clinic for movement disorder patients. Additionally, we have added items for the adverse events observed in pilot DBS for TRD.

During the Controlled Oral Word Association Test (COWAT), individuals are tasked with verbally generating words starting with different letters of the alphabet. They have 60 seconds for each letter to retrieve and articulate as many words as possible. The test involves presenting three letters, each progressively more challenging in associative difficulty. Scores are derived by summing the total words produced across the three letter trials. The lowest achievable score is zero, indicating an inability to generate any words. There is no upper limit to the score as participants can produce numerous words for each letter. Higher scores reflect superior word retrieval and cognitive function.

The Trail-Making Test A and B assess cognitive shifting, visual search speed, scanning, processing speed, mental flexibility, and executive functioning. It evaluates the participant's capacity for sequencing (Parts A and B), cognitive set shifting (Part B), and processing speed (Parts A and B). Scores for Part A and Part B are calculated independently, indicating the number of seconds required for the participant to finish each section. Higher scores denote longer durations for completing the test.

The Rey-Osterrieth complex figure test (ROCF) is a neuropsychological assessment in which patients are asked to reproduce a complicated line drawing, first by copying it freehand (recognition), and then drawing from memory (recall). Scoring of drawings is based on the widely used 36-point scoring system (0 being the worst score and 36 the best).