Table 2 Extracted data from included studies on gender dysphoria and suicidality (including suicidal ideation, suicide attempts and behaviours, suicide risk)

Toomey et al. [39]

USA

Adolescents referred for GD (including AFAB, AMAB, nonbinary, questioning); Cisgender adolescents

120 617

AMAB n = 2020 (0.2%)

AFAB n = 175 (0.1%)

Nonbinary n = 344 (0.3%)

Questioning n = 1052(0.9%)

Female n = 60,973(50.6%)

Male n = 57,871(48%)

11–19 year old

x̄ = 14.7 ± 1.8

Suicide attempts, suicide behaviour

Descriptive statistics

χ²

χ² in R with

Post hoc comparisons

Bivariate level

Logistic regressions

Rates of attempted suicide

AFAB (50.8%)

Nonbinary (41.8%)

AMAB (29.9%)

Questioning (27.9%)

Female (17.6%)

Male (9.8%)

Association between suicide behaviour and gender identity (χ²df = 5] = 2279.2; p < 0.001))

Significant difference between groups except for AMAB and nonbinary (χ²[df = 1] = 0.08; p = 0.78), and AFAB and nonbinary (χ²[df = 1] = 3.66; p = 0.08)

Rates of suicide behaviours:

AFAB: (50.9% [95% CI = 45.51 to 58.17])

Nonbinary: (41.8% [95% CI = 36.57 to 47.22])

AMAB: (30.0% [95% CI = 24.06 to 36.59])

Questioning adolescents: (27.9% [95% CI = 25.27 to 30.69])

Female: (17.6% [95% CI = 17.31 to 17.91])

Male: (9.8% [95% CI = 9.59 to 10.08])

OR (95% CI) for:

Female 1.37% [1.34 to 1.39]

AMAB 1.27% [1.04 to 1.54]

AFAB 1.84% [1.52 to 2.24]

Nonbinary 1.38 [1.20 to 1.58]

Questioning 1.40 [1.28 to 1.52]

Heino et al. [29]

Finland

Adolescents reporting transgender identity (0.2%); other/nonbinary identity (2.9%); cisgender identity (96.9%)

1425

15–16 year old

x̄ = 15.59 ± 0.41

Severe suicidal ideation

Descriptive statistics

Logistic regression for associations between transgender identity and suicidal ideation

Transgender identity reporting severe suicidal ideation significantly more commonly than cisgender identity (14.3 vs. 1.6%, p < 0.001)

OR (95% CI):

Model 1 (controlling for age, sex, honesty of responding): Significant association between transgender status and severe suicide ideation Significantly higher severe suicidal ideation in people identifying themselves as transgender (OR [95% CI] = 10.8[4.0 to 28.9], p < 0.001)

Model 2 (controlling for socioeconomic factors):

Significant association between transgender identity and suicidal ideation = (OR [95% CI] = 9.9 [3.0 to 32.1], p < 0.001)

Model 3 (controlling for depression):

Significant association = (OR [95% CI] = 6.3 [1.6 to 24.9], p = 0.009);

Model 4 (controlling for peer rejection and victimization):

Significant association = (OR [95% CI] = 5.3 [1.3 to 22.1], p = 0.024)

Fisher et al. [17]

Italy

Age-matched GDs

and

NTs control group

92

GDs = 46

NRs = 46

GDs

x̄ = 16 ± 1.49

NRs

x̄ = 16.59 ± 1.11

Suicide risk

(ANCOVA)

Significant difference between GDs and NRs in:

“Attraction to death”: 2.98 ± 0.57 vs. 2.17 ± 0.58; F = 46.22, p < 0.0001 “Repulsion by life” scales: 3.04 ± 0.46 vs. 2.08 ± 0.56, F = 78.5, p < 0.0001 “Attraction to life” scales: 3.32 ± 0.55 vs. 4.05 ± 0.49, F = 44.14, p < 0.0001

Significant difference between GDs and NRs on the “Internalizing scale” (depression/anxiety): 62.43 ± 11.18 vs. 53.57 ± 11.64, F = 12.53 p = 0.001

Yüksel et al. [51]

Turkey

Transgender adolescents

141 diagnosed with transsexuality (DSM-IV)

x̄ = 27.5 ± 7.16

AFAB = 99

AMAB = 42

Suicide attempts, suicidal ideation

Descriptive statistics

χ²

for gender differences

Suicidal rates (%)

Current suicidal thoughts

9.2%

Lifetime suicidal thought

(n = 78) 55.3%

Suicide attempts

(n = 42) 29.8%

Before 21 yr of age:76.7%

After 21 yr of age: 23.3%

Not significant:

Current suicidal thoughts

AFAB-AMAB, χ² = 0.515

Lifetime suicidal thoughts

AFAB-AMAB, χ² = 0.515

Suicide attempts

AFAB-AMAB, χ² = 0.039

de Graaf et al. [24]

Canada, Netherlands, U.K

Adolescents referred for GD

2771

Toronto (n = 260)

Amsterdam (n = 266)

London (n = 2245)

Total sample

x̄ = 15.99 ± 1.20

Toronto

x̄ = 16.66 ± 1.75

Male N (%) 129 (49.6%)

Female N (%) 131 (50.4%)

Amsterdam

x̄ = 15.91 ± 1.42

Male N (%) 123 ± 46.2

Female N (%) 143 ± 53.8

London

x̄ = 15.93 ± 1.07

Male N (%) 685 (30.5%)

Female N (%) 1560 (69.5%)

Suicidality

Comparative analysis

Multiple linear regression analysis

Clinic-referred sample ranges for CBCL:

Item 91 (suicidal ideation) 17.9%—34.9%;

Item 18 (suicidal behaviour) 7.7%—31.1%

Non-referred sample ranges:

Item 91: 1.4%—2.7%;

Item 18: 0.6%—1.8%

Clinic-referred samples ranges for YSR:

Item 91 14.4–31.2.%;

Item 18: 7.5–24.3%

Non-referred sample ranges:

Item 91: 1.5%–7.7%;

Item 18: 2.2–3.9%

Birth assigned sex (predictor)

β = 0.105 (Toronto vs. Amsterdam)

Birth assigned sex β = 0.035 (Toronto vs. London)

Birth assigned sex β = 0.026 (Amsterdam vs. London)

Alizadeh Mohajer et al. [6]

Iran

Individuals diagnosed with GD

21

x̄ = 19

Suicidal ideation

Descriptive statistics

Linear regression analysis

Beck’s Scale for Suicide Ideation

No. (%)

Low Risk 4 (19.1%)

High Risk 15 (71.4%)

Very High Risk 2 (9.5%)

Mean of total score for Beck’s Scale for Suicide Ideation: CI 95%, 11.6 [8.7 to 15.6]