(B)

Clinical Populations (n = 15)
Author(s)	Study Design	Sample			Instrument Assessing MiL	SB-Related Variables
		Population	Size (N)	Psychiatric Diagnosis		SI	SA	Completed Suicide	Other SB-Related Variables and Main Commentaries
Moore, 1997 [42]	Qualitative	Elderly	11	Depression	Hermeneutic analysis	↓	−	−	MiL descriptions were always tied to relational contexts: meaninglessness relative to missing (or perceived to be missing) connectedness
Heisel and Flett, 2004 [43]	Cross-sectional	Adults	49	Various	PIL	↓	−	−	MiL accounted for significant variance in SI—also, a mediation model between satisfaction in life and SI and a moderation model between depression and SI
van Orden et al., 2012 [44]	Longitudinal prospective	Elderly	65	Depression, anxiety	GSIS Perceived MiL subscale	−	−	−	“Perceived burdensomeness” might contribute to suicide morbidity and mortality by eroding MiL
Holm et al., 2014 [45]	Qualitative	Elderly	9	Mood disorder	Hermeneutic analysis	↓	−	−	MiL in the experience of SI was associated with existential aloneness: “Being alone without MiL”
García-Alandete et al., 2014 [46]	Cross-sectional	16–60 yr old	80	Borderline personality disorder	PIL-10	−	−	−	↓ Suicide risk (measured accounting for general suicide risk factors), ↓ depression,↓ hopelessness
van Orden et al., 2015 [47]	Qualitative	Elderly	101	Various	Semi-structured interviews	−		−	“Thwarted belongingness” was associated with more lethal methods and increased re-attempts
Braden et al., 2015 [48]	Cross-sectional	Veterans	110	Depressive disorder	LRI Framework subscale	↓	−	−	The relationship between MiL and SI remained significant after accounting for depressive symptoms, past SA, prior inpatient psychiatric hospitalization, and poor physical health
Marco et al., 2016 [19]	Cross-sectional	13–68 yr old	224	Various	PIL-10	−	−	−	Moderation model: MiL buffered associations between suicide risk factors and hopelessness
Marco et al., 2017a (study 2) [20]	Cross-sectional	13–70 yr old	80	Borderline personality disorder	PIL-10	−	↓	−	MiL was also negatively correlated with other behavioral symptoms of borderline personality disorders, including suicidal threats, high-risk behaviors, drug overdoses, and aggressive behavior
Marco et al., 2017b [49]	Cross-sectional	13–56 yr old	124	Borderline personality disorder	PIL-10	−		−	Moderation model: MiL buffered associations between suicide risk factors and hopelessness
Marco et al., 2017c [50]	Cross-sectional case-control	12–60 yr old	474	Eating disorder	PIL	↓	−	−	Patients with eating disorders had lower MiLs and greater SI than the controls; MiL predicts greater levels of both eating disorder psychopathologies and SI
Pérez Rodriguez et al., 2017a [51]	Cross-sectional	18–60 yr old	150	Various	PIL-10	−	NS	−	Hopelessness (specifically its affective component) differentiated between patients with non-suicidal self-injuries and those with SA but not MiL, which underlies the continuum of self-harm
Pérez Rodriguez et al., 2017b [52]	Cross-sectional	12–60 yr old	348	Various (mainly eating disorder)	PIL-10	−	↓	−	Lower levels of MiL and higher levels of hopelessness, borderline symptoms, and non-suicidal self-injuries were associated with SA in the previous year
Lamis et al., 2018 [53]	Cross-sectional	19–65 yr old	112	Bipolar disorder	SWBS (EWB + RWB)	↓	−	−	Existential MiL but not religious well-being acted as a protective factor against SI among bipolar disorder patients and those who experienced childhood sexual abuse
Florez et al., 2018 [54]	Longitudinal prospective	Disadvantaged African American female survivors of a recent SA	113	PTSD	SWBS (EWB + RWB)	↓	−	−	Mediation model: existential MiL, but not religious well-being, mediated the relationship between PTSD severity and both hopelessness and SI level

Note: MiL = Meaning in Life; SB = suicidal behavior; SI = suicidal ideation; SA = suicide attempt; PIL = Purpose in Life test; LRI = Life Regard Index; GSIS = Geriatric Suicide Ideation Scale; n.sp. = not specified; MLQ = Meaning in Life Questionnaire; 3-item MLQ = 3-item shortened version of the MLQ; EMIL = Experienced Meaning in Life instrument; PIL-10 = 10-item shortened version of the PIL; MLM = Meaningful Life Measure; yr = years; NS = not significant; SWBS = Spiritual Well-Being Scale; EWB = Existential Well-Being subscale; RWB = Religious Well-Being subscale.