Table 1.

Characteristics of included studies.

First author, year of publication, country	Study design [study period]	Study populationa	Study participants [number with psychiatric illness]	Age, yearsb(SD)	Sex (% female)	Type and ascertainment of psychiatric illness	OHCA outcomes and characteristics reported	NOS score
Empana, 2006, USA23	Nested Case-control [1980–1994]	Adults aged ≥ 18 years with OHCA identified from ambulatory medical records; controls matched by age and sex	2,228 Cases/4,164 Controls [300 /327]	Cases: 66.3 (10.2); Controls: 66.2 (9.9)	30.0	Clinical depression, primary care records and antidepressant medication prescriptions	Incidence proportion, sex, comorbidities	5
Wissenberg, 2014, Denmark 29	Retrospective cohort [2001–2010]	People aged ≥ 12 with OHCA with attempted resuscitation (The Danish Cardiac Arrest Registry).	19,372 [2,674]	Median 72; IQR (62–80)	32.6	Psychiatric illness, hospital admission records	Sex	6
Ko, 2016, Canada 27	Retrospective cohort [2005–2010]	Adults aged ≥ 20 years with complete information on OHCA characteristics (RescuNET cardiac arrest Registry)	9,882 [389]	68.8 (16.1)	36.1	Depression, linkage to hospital admission and primary care records	Age and rhythm	6
Rajan, 2016, Denmark28	Retrospective cohort [2005–2012]	People aged ≥ 18 (The Danish Cardiac Arrest Registry)	13,860 [2,146]	Range 58–82	32.1	Psychiatric illness, hospital admission records	Rhythm conversion	6
Ishida, 2019, Japan26	Retrospective cohort [2010–2017]	People aged ≥ 18 with complete information on medical history who had ROSC and transported to Tokyo metropolitan Bokutoh Hospital	649 [49]	Range 18–103	23.8	Psychiatric illness, hospital admission records	Location of arrest and comorbidities	4
Allan, 2018, Canada24	Retrospective cohort [2009–2012]	People aged 2–45, (RescuNET cardiac arrest database)	608 [117]	35.4 (8.9)	23.7	Mood disorder, psychosis, other psychiatric historyc and any psychiatric history, history of psychiatric disease diagnosis or antidepressant or antipsychotic prescription, hospital admission records and prescriptions records	Age and sex	5
Barcella, 2019, Denmark6	Retrospective cohort [2001–2015]	People aged ≥ 18 (The Danish Cardiac Arrest Registry)	27,523 [4,772]	Median 71; IQR (62–81)	31.0	Any psychiatric illness except dementia and mental organic disorder, patients who used antipsychotics and/or lithium and patients who used only antidepressants, medical diagnosis and prescriptions history multisource recordsd	Survival, rhythm, location of arrest, witness status, bCPR, comorbidities and income	8
Ishida, 2020, Japan7	Retrospective cohort [2011–2017]	People aged ≥ 18 with a complete information on medical history who were transported to Tokyo metropolitan Bokutoh Hospital	2,631 [157]	Range 18–108	31.6	Diagnosis of schizophrenia or mood disorders, hospital admission records	Survival, age, sex and rhythm	6
Hulleman, 2020, Netherlands25	Retrospective cohort [2009–2012]	OHCA patients with a complete information on medical history, ARREST registry	1,404 [120]	67.9 (14.5)	20.1	Depression, ascertained through primary care records	Rhythm and location of arrest	4
Barcella, 2021, Denmark 30	Nested Case-control [2001–2015]	People aged 18–100 (The Danish Cardiac Arrest Registry); controls matched by age and sex	35,017 Cases/175,085 Controls [802 /4,009]	Cases: Median 72; IQR (62–81); Controls: Median 72; IQR (62–81)	66.9	Schizophrenia and bipolar disorder, medical diagnosis and prescriptions history multisource recordsd	Incidence proportion and comorbidities	8

bCPR: Bystander Cardiopulmonary Resuscitation; CIHI: Canadian Institute for Health Information; EMS: Emergency Medical Services; IQR: interquartile range; NOS: Newcastle-Ottawa Scale (0–9) OHCA: Out-of-hospital cardiac arrest; ROSC: Return of Spontaneous Circulation; SD: Standard deviation.

^aAll studies excluded OHCAs from presumed non-cardiac causes such as traumas, burns, drowning and electrocution.

^bAge is in mean years (SD) unless otherwise stated.

^cIncludes one diagnosis of obsessive–compulsive disorder, borderline personality disorder, or suicide attempt.

^dDanish Psychiatric Central Research Register, the Danish National Patient Register and the National Prescription Register.