Impact of Community-Based Biofeedback Program on Drug Use and Mental Health Among People Experiencing Homelessness

Commercially available, medical grade photodetector (photoplethysmography or PPG) sensor and accompanying HRV-BF software application (EmWave Pro Plus, HeartMath) will be used to collect interbeat interval data to produce standard measures of HRV including time-domain measures of SDNN (standard deviation of N-to-N intervals) and RMSSD (Root mean square of successive differences between normal heart beats). Both SDNN and RMSSD are measured in milliseconds (ms). RMSSD is most reflective of vagal tone and is our primary outcome measure.

Assessed by the Mental Health Inventory-5 (MHI-5) which has well-demonstrated reliability for detecting psychological disorders with reliabilities of .77 and .71 for women/men, respectively. Minimum = 5; Maximum = 30; Higher score means a better outcome.

Anxiety Symptoms were measured by the Generalized Anxiety Disorder -7, a self-report 7- item measure. Example items include "worrying too much about different things," and "trouble relaxing" (Endpoints 0=not at all; 3=nearly every day). Scores are summed. Severity of anxiety was determined with cut-off scores 5 (mild anxiety), 10 (moderate anxiety), and 15 (severe anxiety). Reliability α=0.87. Minimum = 0; Maximum = 21; Higher score means a worse outcome.

Depressive Symptoms were assessed by the Patient Health Questionnaire-9 (PHQ-9). The PHQ-9 is a brief, 9 question depression module from the full 26-item PHQ. Each of the 9 items address the Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnostic criteria, rating them from "0" (not at all) to "3" (nearly every day). PHQ-9 not only makes criteria-based diagnoses of depressive disorders, but as well can determine severity, with scoring cut-offs for minimal (1-4), mild (5-9), moderate (10-14), moderately severe (15-19) and severe (20-27) depression. Reliability of the PHQ-9 is α=0.89. Minimum = 0; Maximum = 27; Higher score means a worse outcome.

PTSD was measured by means of the Post Traumatic Stress Disorder Checklist-5 (PCL-C), a 17-item screener for PTSD with cut points for symptomatic vs non-symptomatic; scores correlate highly with the Clinician Administered PTSD scale, r = .93.70 The PCL-C has high levels of validity,71 test-retest reliability (r = .96), and high internal consistency (α = .97). The self-report rating scale is 0-4 for each symptom: "Not at All" to "Extremely" (0-80). 5-point change is a minimum threshold for determining a treatment response, while a 10-point change is a minimum threshold for determining a clinically meaningful treatment response. Minimum = 17; Maximum = 85; Higher score means a worse outcome.

Drug and Alcohol Use was assessed by the Texas Christian University (TCU) Drug History Form. It records the frequency of use of 16 drugs used over 12 months, such as heroin and other opiates, street methadone, cocaine, crack, methamphetamine, etc. Yes/No to each drug was assessed for use vs dependency. The total score ranges from 0 - 9; higher scores (> 3) correspond to the DSM 4 drug dependence diagnosis. Minimum = 0; Maximum = 11; Higher score means a worse outcome.

Physical Diseases was assessed by the self-reported comorbidity index (SCQ) for medical problem, treatment, and limitations. PEH were asked to respond if they have chronic health conditions (e.g., heart disease, high blood pressure, diabetes, osteoarthritis). Responses include "yes or no". In a previous PEH sample (N=150), Cronbach's α = .91.

Physical Diseases was assessed by the self-reported comorbidity index (SCQ) for medical problem, treatment, and limitations. PEH were asked to respond if they have chronic health conditions (e.g., heart disease, high blood pressure, diabetes, osteoarthritis. Responses include "yes or no". In a previous PEH sample (N=150), Cronbach's α = .91. Minimum = 0; Maximum = 36; Higher score means a worse outcome.

Urinalysis: In addition, we conducted a urine assay which measures cannabis, methamphetamine, cocaine, and amphetamines. A five-panel Food and Drug Administration-approved urine test cup was used at baseline and 8 week follow-up. The test cup screened for metabolites of Amphetamines (1000 ng/mL), Cocaine (300 ng/mL), Methamphetamines (500 ng/mL), Opiates (2000 ng/mL), and Cannabis (THC) (50 ng/mL).

Social support was measured by the Medical Outcome Study (MOS) Social Support Survey. The MOS is a 19-item instrument and includes four subscales: emotional and informational support; tangible support; positive social interaction; and affectionate support. The MOS uses a Likert-scale, with endpoints 1 (none of the time) to 5 (all of the time) that assesses availability of social support, with higher scores indicating more social support. An overall support index was also calculated.• Minimum = 0; Maximum = 100; Higher score means a better outcome.