Feasibility of Resistance Exercise to Treat Major Depression Via Cerebrovascular Mechanisms: A Pilot Trial

Participant satisfaction (acceptability)

时间窗: Week 26

Participant satisfaction will be assessed using a mixed-method approach, capturing self-reported ratings of satisfaction with the RET program (six questions regarding satisfaction with responses ranging from 0-46, with higher scores indicating greater level of satisfaction) corroborated by a qualitative semi-structured interview, with responses analyzed using a thematic qualitative analysis.

Recruitment and enrollment rates (feasibility)

时间窗: Week 26

Screening responses and timestamps will be used to assess the success of recruitment strategies and recruitment rate, calculated by taking the total number of participants recruited (i.e., completed screening survey) divided by the recruitment period duration. Enrollment rate will be calculated by taking the total number of participants enrolled divided by the recruitment period duration.

Change in depressive symptoms severity via the Quick Inventory of Depressive Symptoms (QIDS)

时间窗: Change from baseline depression symptoms severity at the final assessment

This is a self-administered 16-item questionnaire that assesses the severity of nine depressive symptoms in the last 7 days. Each item is rated on a 4-point scale (0-3), with total scores ranging from 0-27. Higher scores indicate more severe depression.

Change in Transcranial Doppler ultrasound of Middle Cerebral Artery (MCA) blood flow pulsatility

时间窗: Change in baseline blood flow pulsatility at the final assessment

Middle Cerebral Artery (MCA) blood flow pulsatility will be measured under supine, resting conditions using non-invasive techniques following 10 min of quiet rest in a dimly lit room. It will be assessed in duplicate and averaged for analyses. Measurements will be taken from the left middle cerebral artery (MCA) following standardized, recommended insonation protocols using a 2-MHz Transcranial Doppler (TCD) probe secured to the temporal window via a headset. Cerebral pulsatility will be quantified using the pulsatility index, calculated as (systolic -diastolic velocity)/mean velocity using TCD, averaged over a 60-sec epoch.

Retention (acceptability)

时间窗: Week 26

The retention rate will be calculated based on the percentage of participants that complete all study visits.

Change in level of commitment

时间窗: Change from week 1 level of commitment at week 16

Participants will be asked to report their current level of commitment to the 16-week program and attending their next exercise session via a visual analogue scale anchored with "0" (0% committed) to "100" (100% committed). They subsequently responded to free-text questions related to what they needed to do or what the research team could do to increase their level of commitment. Next, they answered the question "Will you attend your next RET session?" (yes/no response buttons), and then provided an electronic signature confirming they would attend.

Change in Transcranial Doppler ultrasound of Middle Cerebral Artery (MCA) blood flow velocity

时间窗: Change in baseline blood flow velocity at the final assessment

Middle Cerebral Artery (MCA) blood flow velocity will be measured under supine, resting conditions using non-invasive techniques following 10 min of quiet rest in a dimly lit room. It will be assessed in duplicate and averaged for analyses. Measurements will be taken from the left middle cerebral artery (MCA) following standardized, recommended insonation protocols using a 2-MHz Transcranial Doppler (TCD) probe secured to the temporal window via a headset. MCA mean blood velocity will be calculated using a standard algorithm implemented on the device, averaged over a 60-sec epoch.

Adherence (acceptability)

时间窗: Week 26

The adherence rate will be calculated based on the percent of total study visits (i.e., assessment visits and RET sessions) completed within +/-7 days of the scheduled visit date for each participant.

Change in exercise preparation habit ratings

时间窗: Change from week 1 habit ratings at week 16

To facilitate exercise adherence, participants will develop exercise preparation habit action and coping plans during their baseline visit. These plans will subsequently be assessed weekly during exercise sessions, with participants responding to 3 questions regarding their success in developing exercise preparation habits. Using a 5-point Likert scale ranging from "Never" to "Every Time", participants will report 1) how well they were able to stick to their exercise preparation habit action and coping plans, 2) carried through with preparation steps when their identified cue was encountered, and 3) completed the habit without the planned cue. They were also provided an opportunity to revise their habit action and coping plan if their current plan was not successful the previous week.

Change in depression symptom severity via GRID-Hamilton Depression Rating Scale (HAM-D)

时间窗: Change from baseline depression severity at the final assessment

The GRID-HAM-D is a clinician-completed questionnaire that will be used to rate depressive symptom severity. The questionnaire is designed for adults and is used to rate the intensity and frequency of depressive symptoms by probing mood, feelings of guilt, suicidal ideation, insomnia, agitation or retardation, anxiety, weight loss, and somatic symptoms. Clinical Interviewers will follow the Structured Interview Guide and use GRID scoring, in which dimensions of intensity and frequency of a symptom are rated independently for each item. Higher scores reflect greater symptom severity, categorized as Normal (0-7), Mild Depression (8-13), Moderate Depression (14-18), Severe Depression (19-22), and Very Severe Depression (\>23).

Change in depression diagnosis via Structured Clinical Interview for DSM-5 Disorders (SCID)

时间窗: Change from baseline depression diagnosis at the final assessment

This is a clinician-administered semi-structured interview guide for making diagnoses according to the diagnostic criteria published in the American Psychiatric Association's Diagnostic and Statistical Manual for Mental Disorders (DSM-5). It provides diagnoses for depressive and bipolar disorders, schizophrenia spectrum and other psychotic disorders, substance use disorders, anxiety disorders (panic disorder, agoraphobia, social anxiety disorder, generalized anxiety disorder), obsessive-compulsive disorder, posttraumatic stress disorder, attention-deficit/hyperactivity disorder, and adjustment disorder. The SCID will be administered by a Clinical Interviewer to diagnose Major Depressive Disorder and assess for exclusion criteria in this study.