Individual-Level Risk and Resilience Factors Associated with Mental Health in Siblings of Individuals with Neurodevelopmental Conditions: A Network Analysis

Figures & data

Table 1. Demographics of participants.

Variable	Category	NDC n (%)	Control n (%)	Total N (%)	p-value	Effect Size
Sample		235	480	715
Age	Mean (SD)	22.07 (10.03)	22.56 (8.40)	22.40 (8.96)	0.52	0.05
	Range (years)	8–65	13–60	8–65
	8–13 years	46 (19.57)	29 (6.04)	75 (10.49)
	14–18 years	64 (27.23)	123 (25.63)	187 (26.15)
	19–24 years	41 (17.45)	150 (31.25)	191 (26.71)
	25–29 years	42 (17.87)	109 (22.71)	151 (21.12)
	30–39 years	26 (11.06)	29 (6.04)	55 (7.69)
	40+ years	16 (6.81)	20 (4.17)	36 (5.03)
Gender	Female	166 (70.64)	379 (78.96)	545 (76.22)	<.001	0.06
	Male	55 (23.40)	90 (18.75)	145 (20.28)
	Non-conforming	2 (0.85)	5 (1.04)	7 (0.98)
	Prefer not to say	0	1 (0.21)	1 (0.14)
	Prefer to self describe	8 (3.40)	3 (0.63)	11 (1.54)
	Trans-female	0	1 (0.21)	1 (0.14)
	Trans-male	2 (0.85)	1 (0.21)	3 (0.42)
No. siblings	1	105 (44.68)	263 (55.0)	368 (51.47)	0.02	0.06
	2	63 (26.81)	135 (28.13)	198 (27.69)
	3+	67 (28.51)	82 (17.08)	149 (20.84)
NDC sibling age	Mean (SD)	20.19 (9.02) [8–60]	19.97 (7.48) [8–69]	20.04 (8.03)	0.75	0.03
NDC sibling gender	Female	194 (43.89)	382 (48.29)	576 (54.70)	0.71	0.03
	Male	242 (54.75)	390 (49.30)	632 (60.02)
	Other	6 (2.29)	19 (2.40)	25 (2.37)
Country of origin*	Australia	171 (72.77)	426 (88.75)	597 (83.50)	<0.001	0.19
	Outside Australia (Europe, USA, Asia, Canada, New Zealand)	64 (27.23)	54 (11.25)	118 (16.50)
Parental ethnicity	White (Australian, European, New Zealand, American)	192 (81.70)	336 (70)	528 (73.85)	<0.001	0.08
	Southern, Eastern Asian	13 (5.53)	103 (21.46)	116 (16.22)
	Indigenous Australian (Aboriginal and/or Torres Strait Islander)	12 (5.11)	5 (1.04)	17 (2.28)
	Middle Eastern	4 (1.70)	11 (2.29)	15 (2.10)
	Black African	0	7 (1.46)	7 (0.98)
	Hispanic or Latino	3 (1.28)	4 (0.83)	7 (0.98)
	Central Asian	2 (0.85)	4 (0.83)	6 (0.84)
	Indigenous (First) people of another country (not in Australia)	5 (2.13)	1 (0.21)	6 (0.84)
	North Asian	0	6 (1.25)	6 (0.84)
	Other	3 (1.28)	1 (0.21)	4 (0.56)
	Pacific Islander	0	2 (0.42)	2 (0.28)
Household income yearly	$0–$25k	29 (12.34)	51 (10.63)	80 (11.19)	0.10	0.05
(AUS$)	$26k-$50k	20 (8.51)	31 (6.46)	51 (7.13)
	$51k-$75k	18 (7.66)	52 (10.83)	70 (9.79)
	$76k-$100k	12 (5.11)	48 (10)	60 (8.39)
	$101k-$200k	47 (20)	100 (20.83)	147 (20.56)
	$201k+	13 (5.53)	32 (6.67)	45 (6.29)
	Unsure	40 (17.02)	109 (22.71)	149 (20.84)
	Not comfortable answering	19 (8.09)	32 (6.67)	51 (7.13)
Parent NDC status	Neither parent with an NDC	177 (75.32)	431 (89.79)	608 (85.03)	<0.001	0.14
	One parent with an NDC	52 (22.13)	46 (9.58)	98 (13.71)
	Both parents with an NDC	6 (2.55)	3 (0.63)	9 (1.26)
Age parent 1	Mean (SD)	50.83 (10.48)	52.37 (10.11)	51.87 (10.29)	0.07	0.15
Age parent 2	Mean (SD)	52.85 (10.38)	55.04 (10.59)	54.33 (10.49)	0.01	0.21
Parental divorce
	Parents are divorced or separated	79 (33.62)	115 (23.96)	194 (27.27)
# siblings with an NDC	No NDC		480	480 (67.13)
	1 sibling diagnosed	209 (88.94)
	2+ siblings diagnosed	26 (11.06)
Single NDC prevalence**	ADHD	69 (29.36)
	Intellectual Disability	63 (26.81)
	Autism	57 (24.26)
	Epilepsy	32 (13.62)
	Fetal Alcohol Spectrum Disorder	24 (10.21)
	Cerebral Palsy	21 (8.94)
	Rett Syndrome	20 (8.51)
	22q11.2 Deletion Syndrome	10 (4.26)
	MECP2 Duplication Disorder	10 (4.26)
# siblings with chronic illness	No sibling with a chronic illness	153 (65.10)	456 (95)	609 (85.17)	<.001	0.39
	At least one sibling with a chronic illness	82 (34.90)	24 (5)	106 (14.83)

Note: Effect sizes are in Cramer’s V for all variables except age, which is in Hedge’s g.

Total N of participants’ siblings in the NDC group includes all siblings which were reported on, including those without an NDC (i.e., n = 442 for the NDC group, 791 for the control group). Percentages for NDC type is relative to the sample size of 262, being participants’ siblings who were reported on and who had an NDC.

* Outside of Australia, country of origin included: Canada (17), China (7), Denmark (7), Fiji (2), Greece (1), Indonesia (6), Ireland (2), Italy (1), Myanmar (1), Netherlands (1), New Zealand (7), Norway (4), Singapore (6), Sweden (2), Taiwan (2), United Kingdom (16), United States (24), Vietnam (2).

** Single NDC prevalence indicates the percentage of participants’ siblings with a particular NDC, irrespective of co-occurring NDCs (i.e., there is some overlap in these estimates). Only those with frequencies over 10 are listed. The percentage is occurrence amongst all participants’ siblings in the NDC group. For specific clinical presentations, please refer to the rows above this section which list the NDCs and their co-occurrences.

Figure 1. The GGM estimated for the subsamples, on the left (A) is the control group and on the right (B) is the NDC sibling group.

Note: Key: GAD: generalised anxiety disorder; PHQ: depression; SWL: life satisfaction; YEBS-H: hyperactivity/externalising behaviour; YEBS-A: attention difficulties; AQ: autistic traits; FLE: cognitive inflexibility; PAQ: alexithymia; PERS-P: positive emotion reactivity; PERS-N: negative emotion reactivity; ERQ-C: cognitive reappraisal emotion regulation; ERQ-E: expressive suppression emotion regulation; IUS: intolerance of uncertainty; CDR: trait resilience; RSE: self-esteem; AME cognitive empathy; PAC: parent-child communication quality.

Figure 2. Measures of centrality for the GGMs estimated for the subsamples, on the left (A) is the control group and on the right (B) is the NDC sibling group.

Note. The x-axis depicts z-scores, rather than raw centrality indices.

Figure 3. Network tree estimated for demographic predictor variables.

Data availability statement

The analytic code and participant data necessary to reproduce the analyses presented are available on the first author’s OSF page: https://osf.io/6w7ar/