Table 1.

Summary of twenty-eight studies included in this review

Study ID and Authors	Country & Setting	Study Design	Caregiving domains measured	t-test, p and Cohen’s d derived from M(SD) of SSD and BD comparisons	Key Findings
1. Blanthorn-Hazell et al. [52]	Germany, Spain & UK, community mental health	Cross-sectional	Burden	t(240) = 0.30, p = .764, d = 0.04	- Caring for those with either SCZ or BD with agitation confers substantial and similar burden.
2. Chadda et al. [53]	India, psychiatric outpatient clinic	Prospective cohort	Burden	t(198) = 0.78, p = .437, d = 0.11	- Both caregiver groups experienced similar levels of burden, with no significant differences between caregiving groups.
3. Chakrabarti and Gill [54]	India, psychiatric hospital	Cross-sectional	Burden	t(56) = 3.42, p < .01, d = 0.88	- Total burden scores were significantly greater for caregivers of those with SCZ than BD.
4. Chakrabarti et al. [55]	India	Cross-sectional/ psychometric validation	Distress	Information not available	- There were no differences in distress between caregivers of those with SCZ and BD.
5. Chang et al. [56]	Taiwan, four hospitals	Cross-sectional	Burden, Depression, Anxiety	No total burden score available Depression Total Score t(298) = 0.98, p = .326, d = 0.12 Anxiety Total Score t(298) = 0.72, p = .470, d = 0.09	- There were no significant differences in burden experienced between both caregiver groups. - No significant differences between groups on measures of depression and anxiety.
6. Chien et al. [57]	Hong Kong & China, two psychiatric outpatient clinics	Cross-sectional/ psychometric validation	Burden	t(128) = 0.40, p = .690, d = 0.11	- Level of family burden was not statistically significant between caregiver groups.
7. Fekih-Romdhane et al. [58]	Tunisia, psychiatric hospital	Cross-sectional	Burden	t(43) = 1.99, p = .053, d = 0.61	- No significant differences in burden experienced between caregivers based on diagnosis.
8. Grover et al. [59]	India, tertiary-care teaching hospital	Cross-sectional	Burden, Distress	Total Burden score t(138) = 2.92, p < .01, d = 0.49 Distress comparison data not available	- Overall negative caregiving experience was higher in SCZ group compared to BD. - Positive personal caregiver experience was significantly higher in caregivers of those with SCZ compared to BD. - No significant differences between caregivers on measure of psychological distress.
9. Grover et al. [60]	India, psychiatry outpatient clinic	Cross-sectional	Burden	Information not available	- Caregivers of those with SCZ had significantly higher moderate to severe objective burden compared to caregivers of those with BD. - Caregivers of those with BD has significantly higher subjective burden compared to caregivers of those with SCZ.
10. Grover et al. [61]	India, psychiatry hospital	Cross-sectional	Burden	Objective Burden Score t(98) = 1.63, p = .107, d = 0.33 Subjective Burden Score t(98) = 3.67, p < .001, d = 0.74	- Caregivers in SCZ group had significantly higher objective burden, subjective burden, and disruption to routines.
11. Grover et al. [62]	India, 14 national mental health centres	Cross-sectional	Distress	t(1049) = 1.28, p = .200, d = 0.09	- Caregivers of those with SCZ had significantly higher distress compared to caregivers of individuals with BD.
12. Ak et al. [63]	Turkey, inpatient psychiatric unit	Cross-sectional	Burden	Information not available	- Caregiving burden was high across both groups, but no statistical difference was found.
13. Nehra et al. [64]	India, hospital	Cross-sectional	Burden	Total Objective Burden Score t(98) = 0.97, p = .334, d = 0.19	- All differences were non-significant between the two groups.
14. Ramírez et al. [65]	Colombia, Mood Disorders and Psychosis Clinic	Randomized-controlled trial	Burden	Information not available	- When comparing scores between the BD and schizophrenia groups, no statistically significant differences were found.
15. Rodrigo et al. [66]	Sri Lanka, psychiatric hospital unit	Prospective cohort and cross-sectional	Burden, Depression	Information not available	- No significant differences between groups based on individual diagnosis were found on measures of burden and depression.
16. Roychaudhuri et al. [67]	Nigeria, psychiatric teaching hospital	Cross-sectional	Burden	Total Objective Burden Score t(52) = 0.73, p = .467, d = 0.20 Subjective Positive Appraisal t(52) = 1.65, p = .104, d = 0.45 Subjective Negative Appraisal t(52) = 2.23, p < .05, d = 0.62	- Statistically significant differences between caregivers of those with SSD and BD were only observed in subjective negative burden domain.
17. Sharma et al. [68]	Nepal, psychiatric inpatient unit	Cross-sectional	Burden, Depression, Anxiety	Burden Total Score t(98) = 0.48, p = .632, d = 0.09 Depression Total Score t(98) = 0.57, p = .572, d = 0.11 Anxiety Total Score t(52) = 0.67, p = .504, d = 0.13	- There were no statistically significant differences on burden, depression and anxiety based on individual diagnosis alone. - Spouses of individuals with SCZ had significantly higher stress levels than spouses of individuals with BD.
18. Singh and Prajapati [69]	Nepal, transit home	Cross-sectional	Burden	Information not available	- Moderate caregiving burden was statistically higher in caregivers of those with SCZ compared to caregivers of those with BD.
19. Vasudeva et al. [70]	India, tertiary care hospital	Cross-sectional	Burden	t(101) = 2.15, p < .05, d = 0.42	- Both caregiver groups experience considerable burden, but global burden in caregivers of those with SCZ was significantly higher than in BD group.
20. Webb et al. [71]	USA, hospital inpatient and outpatient programs	Cross-sectional	Burden, Psychological wellbeing	Total Burden Score t(82) = 1.45, p = .151, d = 0.33 Total Wellbeing Score t(82) = 1.97, p = .052, d = 0.17	- No significant differences related to diagnosis of individual were found.
21. Zendjidjian et al. [72]	France, psychiatric hospital unit	Cross-sectional	Mental Health	Mental Health Composite Score t(359) = 2.23, p < .05, d = 0.24	- Caregivers of individuals with SCZ reported significantly lower mental health outcome scores compared to caregivers of those with BD.
22. Zhou et al. [73]	China, nine psychiatric units	Cross-sectional	Burden, Depression, Anxiety	Information not available	- Caregivers of those with BD reported greater burden, regarding violent and suicidal behaviours from individuals, compared to caregivers of those with SCZ.
23. Abdeta and Desalegn [74]	Ethiopia, university hospital	Cross-sectional	Presence of common mental disorders	Information not available	- No significant differences were noted in the percentage of caregivers presenting with common mental disorders (anxiety and depression).
24. Cohen et al. [75]	Brazil, outpatient teaching hospital	Cross-sectional	Mental health, Depression, Psychological outcomes	Mental Health Composite score t(123) = 0.97, p = 0.332, d = 0.17 Psychological Outcomes score t(123) = 1.02, p = 0.311, d = 0.18 Total Depression score t(123) = 2.92, p < 0.01, d = 0.52	- Caregivers of individuals with SCZ had significantly higher depressive symptoms compared to caregivers of those BD. - No significant differences were observed on the mental health and psychological outcome scores between caregiver groups.
25. Ukpong and Ibigbami [76]	Nigeria, outpatient psychiatric clinics	Cross-sectional	Burden, Depression, Anxiety, Psychological outcomes	Total Burden score t(198) = 5.19, p > 0.001, d = 0.73 Total Anxiety score t(198) = − 0.17, p = 0.867, d = 0.02 Total Depression score t(198) = 3.25, p < 0.001, d = 0.46 Total Psychological outcomes score t(198) = 2.62, p < 0.01, d = 0.37	- Burden was significantly higher in caregivers of individuals with SCZ compared to caregivers of those with BD. - Caregivers did not significantly differ in anxiety experienced. - Caregivers of those with BD reported significantly higher depression scores than caregivers of those with SCZ. - Caregivers of those with SCZ reported significantly lower psychological outcome scores compared to caregivers of those with BD.
26. Udoh et al. [77]	Nigeria, neuropsychiatric hospital	Cross-sectional	Burden, Psychological Distress	Burden Total Score t(128) = 2.39, p < 0.05, d = 0.45 Psychological Distress Total Score t(128) = 0.48, p = 0.63, d = 0.08	- No significant differences in caregiver burden were reported between caregivers of individuals with SCZ or BD. - Caregivers of individuals with SCZ reported higher levels of psychological distress compared to caregivers of those with BD.
27. Asl et al. [78]	Iran, university psychiatric institute	Descriptive analytical	Burden, Depression, Anxiety, Psychological distress	Total Burden Score t(298) = 0.45, p = 0.65, d = 0.05 Depression, Anxiety and Stress Composite Score t(298) = 0.02, p = 0.99, d < 0.01	- No significant differences in caregiver burden were observed between caregivers of individuals with SCZ or BD. - No significant differences in depression, anxiety or distress were observed between caregivers of individuals with SCZ or BD.
28. Khatoon et al. [79]	India, psychiatric hospital	Cross-sectional	Burden	Total Objective Burden Score t(58) = 2.06, p < 0.05, d = 0.53	- Caregivers of those with SCZ presented with significantly higher caregiver burden on subscales of total objective burden, subjective burden, financial burden, disruption to family activities, disruption to family leisure and disruption to family interaction. - There were no significant differences in caregiver burden observed between caregivers of individuals with SCZ or BD on the clinician-rated objective burden subscale, and burden subscales on effects on physical and mental health.

SSD schizophrenia spectrum disorder, SCZ schizophrenia, BD bipolar disorder, M mean, SD standard deviation