Key characteristics of the studies included in this meta-analysis.

Table 1: Key characteristics of the studies included in this meta-analysis.

Study name	r	n	Gratitude measure	Depression measure	Cross¹/Long²	% Female	Mean age	Country of research	Sample description
Alkozei, et al. [31]	-0.57	88	GRAT	BDI-II	Cross	47	19	USA	Undergraduates
Allenden, et al. [32]	-0.37	278	GQ-6	CES-D	Cross	64	65³	Australia	Retirees
Begg [33] thesis	-0.47	649	GQ-6	DASS-21⁴	Cross	79	31	Australia	Adults
Bryan, et al. [42]	-0.46	352	GQ-6	BSI	Cross	84	24	USA	Undergraduates
Celano, et al. [43]	-0.50	164	GQ-6	PHQ-9	Cross	16	61	USA	Cardiac patients
Chamizo-Nieto, et al. [44]	-0.28	835	GQ-6⁵	DASS-2¹⁴	Cross	54	16	Spain	Adolescents
Corona, et al. [45] study 2 a	-0.54	121	GQ-6	CES-D	Cross	84	21	USA	Undergraduates
Corona, et al. [45] study 2 b	-0.42	91	GQ-6	CES-D	Cross	87	21	USA	Undergraduates
Crouch, et al. [46]	-0.53	128	GQ-6	HADS	Cross	69	50	USA	MS patients
Deichert, et al. [47]	-0.42	181	GQ-6	CES-D	Cross	66	21	USA	Students
Disabato, et al. [2]	-0.33	797	GQ-6	CES-D	Long	83	39	43 countries	Adults
Enko [48]	-0.30	196	GQ-6	CES-D	Cross	51	21	Poland	Students
Fenollar Bataller [49]	-0.41	48	GQ-6	CES-D	Cross	67	37	USA	Religious congregation
Froh, et al. [50]	-0.43	1035	GQ-6: GRAT: GAC	CES-D Children	Cross	49	16	USA	High school students
Gavian [51] dissertation	-0.57	271	GQ-6	DASS-21⁴	Cross	70		USA	Undergraduates
Greene and McGovern [52]	-0.37	350	GQ-6	PHQ-9	Cross	89	40	21 countries	Death of a parent prior to age 18
Harbaugh [53] dissertation	-0.48	164	GQ-6	CES-D	Long	70	20	USA	Undergraduates
Hoffman [54]	-0.69	38	GQ-6	RDSI	Cross	37	61⁶	USA	Head and neck cancer group
Kaniuka, et al. [55]	-0.41	913	GQ-6	BDI-II	Cross	72	20	USA	Undergraduates
Kashdan and Breen [56]	-0.35	144	GQ-6	BDI-II	Cross	78	24	USA	Undergraduates
Kleiman, et al. [57]	-0.36	369	GQ-6	BDI-II	Cross	85	22	USA	Undergraduates
Koenog, et al. [58]	-0.31	129	GQ-6	BDI-II	Cross	70	51	USA	Religious adults
Lambert, et al. [3]	-0.29	746	GQ-6	CES-D	Long	83	19⁶	USA	Undergraduates
Langer, et al. [59]	-0.53	331	GQ-6	DASS-21⁴	Cross	70	38	Chile	Adults
Lau and Cheng [60]	-0.17 -0.12	101	GQ-6: GAC	CES-D	Cross	82	58	China	Caregivers
Lee, et al. [61]	-0.45	464	GQ-6⁷	HADS	Cross	0		South Korea	Firefighters
Li, et al. [62]	-0.03	321	GQ-6⁸	CES-D⁸	Cross	0		China	HIV infected men who have sex with other men
Liang, et al. [63]	-0.40	501	GQ-6	CES-D	Cross	52	20	China	Undergraduates
Lin [9]	-0.31	235	GQ-6⁸	CES-D⁸	Cross	62	20	Taiwan	Students
Lin [64]	-0.34	814	IUG⁸	CES-D⁸	Cross	68	20	Taiwan	Undergraduates
Lin [65]	-0.47	287	IUG⁸	CES-D⁸	Cross	77	20	Taiwan	Undergraduates
Liu, et al. [40]	-0.31	445	GRAT	SDS	Cross	75	24	China	Undergraduates
Mann [66]	-0.30	333	GQ-6	CES-D	Cross	67	25	43 Countries	Modern orthodox single adults
Martin, et al. [67]	-0.14	108	GQ-6	HADS	Long	86	39	UK	Parents of children with a disability
McCullough, et al. [5] study 1	-0.30	238	GQ-6	BSI	Cross	73	21	USA	Undergraduates
Mills, et al. [68]	-0.46	186	GQ-6	BDI	Cross	5	66		Heart failure patients
Olawa and Idemudia [69]	-0.27	465	GQ-6	GDS	Cross	63	74	Nigeria	Older adults
Padilla-Walker, et al. [11]	-0.18	500	GQ-6	CES-D children	Long	52	13	USA	Adolescents
Petrocchi and Couyoumdjian [70]	-0.45	410	GQ-6	CES-D	Cross	61	33	Italy	Adults
Renshaw and Rock [71]	-0.40	97	GQ-6	DASS-21⁴	Cross	86	20	USA	Undergraduates
Rey, et al. [12]	-0.49	1617	GQ-6⁵	CDI-S⁵	Cross	50	14	Spain	Adolescents
Rey, et al. [72]	-0.47	569	GQ-6⁵	CDI-S⁵	Cross	49	15	Spain	Adolescents
Ruini and Vescovelli [14]	-0.36	67	GQ-6	SQ	Cross	100	57	Italy	Breast cancer patients
Sánchez-Álvarez, et al. [73]	-0.48	1661	GQ-6	CDI-S⁵	Cross	50	14	Spain	Students
Sánchez‐Álvarez, et al. [74]	-0.27	2500	GQ-6	DASS-21⁴	Long	58	34	Spain	Adolescents and adults
Sánchez‐Álvarez, et al. [75]	-0.42	1013	GQ-6	BDI-II	Cross	51	40	Spain	Adults
Sherman, et al. [76]	-0.48	64	GQ-6	HADS	Long	43	28	USA	Cystic fibrosis patients
Simon [77]	-0.45	477	GQ-6	MINI-MASQ	Cross	57	19	Philippines	Undergraduates
Sirois and Wood [15] arthritis	-0.50	423	GQ-6	CES-D	Cross	88	45	UK	Arthritis patients
Sirois and Wood [15] IBD	-0.49	427	GQ-6	CES-D	Cross	77	36	UK	IBD patients
Stoeckel, et al. [78]	-0.36: -0.48	136	GQ-6: GRAT	CES-D	Cross	47	19	USA	Undergraduates
Tam, et al. [13]	-0.39	439	GQ-6⁸	HADS⁶	Cross	53	10	China	Children
Tehranchi, et al. [79]	-0.16	200	VIA-IS-240	BDI-II	Cross	69	30	Iran	Adults diagnosed with MDD
Tulbure [80]	-0.36	113	GQ-6	BDI-II	Cross	70	33	Romania	Adults
Van Dusen [81] thesis	-0.45: -0.47	93	GQ-6: GRAT	CES-D	Cross	80	19	USA	Undergraduates
Van Dusen [82] dissertation	-0.35	268	GQ-6	PHQ-9	Cross	66	47	USA	Medical centre patients
Van Dusen, et al. [83]	-0.36	389	GQ-6	PHQ-9	Cross	75	20	USA	Undergraduates with trauma
Watkins, et al. [16] study 2 population 1	-0.34	154	GRAT	BDI-II	Cross			USA	Undergraduates
Watkins, et al. [16] study 2 population 2	-0.54	66	GRAT	BDI-II	Cross			USA	Undergraduates
Watkins, et al. [16] study 2 population 3	-0.56	57	GRAT	BDI-II	Cross			USA	Undergraduates
Wood, et al. [84] study 1	-0.24	156	GQ-6	CES-D	Long	51		UK	Undergraduates
Wood, et al. [84] study 2	-0.48	87	GQ-6	CES-D	Long	86		UK	Undergraduates
Wood, et al. [85]	-0.31	201	GQ-6	NEO-PI-R	Cross	64		UK	Undergraduates
Wu, et al. [86]	-0.38	358	GQ-6⁸	TDS⁸	Cross	63	19	China	Undergraduates
Yuan, et al. (Unpublished)	-0.37	389	GRAT	CES-D	Cross	64	21	China	Undergraduates
Zhang, et al. [87]	-0.42	468	GQ-6	DASS-21⁴	Cross	58	19	China	Undergraduates
Zhang, et al. [88]	-0.45	112	GQ-6	CES-D	Cross	42	21	China	Adults with a disability

GRAT: Gratitude Resentment and Appreciation Scale [16]; GQ-6: The Gratitude Questionnaire [5]; GAC: The Gratitude Adjective List [5]; IUG: Inventory of Undergraduates Gratitude [89]; VIA-IS-240: VIA Inventory of Strengths [90]; BDI-II: Beck Depression Inventory-II [23]; DASS-21: Depression Anxiety and Stress Scale [20]; CES-D: Center for Epidemiologic Studies Depression Scale [18]; CES-D Children: Center for Epidemiologic Studies Depression Scale for Children [91]; BSI: Brief Symptom Inventory [92]; PHQ-9: Patient Health Questionnaire (Spritzer, et al.); HADS: Hospital Anxiety and Depression Scale [24]; RDSI: Reynolds Depression Screening Inventory [93]; MINI-MASQ: Mini Mood and Anxiety Symptom Questionnaire [94)]; SDS: Self-rating Depression Scale [95]; GDS: Geriatric Depression Scale [96]; CDI-S: Children's Depression Inventory Short Version [97]; SQ: Symptom Questionnaire [98]; NEO-PI-R: Revised neo personality inventory (Costa & McRae); TDS: Trait Depression Subscale of the State-Trait Depression Questionnaire [99].