Adj R2	Adjusted R Square
AIC	Akaike Information Criterion
APC	Amemiya Prediction Criterion
BAFFS	Brief Assessment of Family Functioning Scale
BRS	Brief Resilience Scale
BS-6-SC	Brief Social Support Scale
BTQ	Brief Trauma Questionnaire
CAS	Coronavirus Anxiety Scale
DS	Demoralization Scale
DS-II	DS-II: Demoralization Scale-II
FC-19S	Fear of COVID-19 Scale
GAD-7	Generalized Anxiety Disorder-7
GPCOG	General Practitioner Assessment of Cognition Screening Test
HRQoL	Health-related quality of life
H-Y	Hoehn and Yahr staging system
IES	Impact of Event Scale
ISEL-SF	Interpersonal Support Evaluation List Short Form
LON	LON: 3-item version of the R-UCLA Loneliness Scale
MDS-UPDRS-m	Part III of the Movement Disorder Society Sponsored Revision of the Unified Parkinson Disease Rating Scale for motor symptoms
MPC	Mallows’ Prediction Criterion
OCS	Obsession with COVID-19 Scale
PD	Parkinson disease
PDHRQoL	Parkinson disease health-related quality of life
PDQ-8	Parkinson Disease Questionnaire-8
PHQ-9	Patient Health Questionnaire
PTSD	Post-traumatic stress disorder
PC-PTSD-5	Primary Care PTSD-5 Scale
R2	R Square
SBC	Schwarz Bayesian Criterion
SF-36	36-item Short Form Survey
SIS	Subjective Incompetence Scale
SSE	Standard Error of the Estimate