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. Author manuscript; available in PMC: 2024 Jun 11.
Published in final edited form as: Personal Disord. 2023 Jul 27;15(1):34–45. doi: 10.1037/per0000635

Table 2.

Univariate Parameter Estimates and Fit Statistics for Loneliness and the AMPD Traits

Variable MZ pairs DZ pairs MZ ICC DZ ICC A [95% Cl] D [95% Cl] C [95% Cl] E [95% Cl] AIC
Loneliness 419 258 0.37 0.16 0.24 [−0.22–0.69] 0.14 [−0.32–0.63] — 0.62 [0.54–0.71] 3.778.2
0.38 [0.28–0.47] — — 0.62 [0.55–0.71] 3,776.5
Negative affect 415 254 0.36 0.22 0.27 [0.00–0.56] — 0.08 [−0.16–0.32] 0.64 [0.56–0.73] 3.727.4
0.37 [0.28–0.46] — — 0.63 [0.56–0.71] 3,725.9
 Anxiousness 415 254 0.41 0.24 0.28 [0.00–0.57] — 0.12 [−0.14–0.36] 0.60 [0.53–0.68] 3.713.0
0.41 [0.32–0.49] — — 0.59 [0.52–0.67] 3,711.9
 Emotional lability 415 254 0.26 0.18 0.20 [−0.09–0.49] — 0.07 [−0.18–0.31] 0.73 [0.64–0.83] 3.760.0
0.28 [0.19–0.37] — — 0.72 [0.64–0.81] 3,758.3
 Hostility 415 254 0.34 0.10 0.09 [−0.43–0.60] 0.24 [−0.28–0.79] — 0.67 [0.59–0.76] 3.754.2
0.32 [0.23–0.41] — — 0.68 [0.60–0.77] 3,753.0
 Perseveration 415 254 0.34 0.20 0.31 [0.04–0.61] — 0.04 [−0.21–0.27] 0.65 [0.57–0.75] 3.744.1
0.35 [0.26–0.45] — — 0.65 [0.57–0.73] 3,742.2
 Restricted affectivity 415 254 0.33 0.14 0.21 [−0.28–0.68] 0.13 [−0.36–0.64] — 0.66 [0.58–0.76] 3.753.1
0.33 [0.24–0.42] — — 0.67 [0.59–0.76] 3,751.4
 Separation anxiety 415 254 0.22 0.12 0.17 [−0.13–0.49] — 0.04 [−0.23–0.30] 0.79 [0.69–0.89] 3.772.7
0.22 [0.13–0.30] — — 0.78 [0.69–0.88] 3,770.8
 Submissiveness 415 254 0.38 0.16 0.23 [−0.26–0.69] 0.16 [−0.32–0.67] — 0.62 [0.54–0.71] 3.735.2
0.37 [0.28–0.47] — — 0.63 [0.55–0.71] 3,733.6
Detachment 415 254 0.38 0.21 0.31 [0.04–0.61] — 0.06 [−0.20–0.30] 0.63 [0.55–0.71] 3.728.7
0.38 [0.29–0.47] — — 0.62 [0.55–0.70] 3,726.9
 Anhedonia 415 254 0.35 0.14 0.29 [−0.24–0.79] 0.04 [−0.47–0.59] — 0.67 [0.58–0.75] 3.744.8
0.33 [0.24–0.42] — — 0.67 [0.59–0.75] 3,742.8
 Depressivity 415 254 0.21 0.14 0.14 [−0.16–0.44] — 0.07 [−0.20–0.32] 0.79 [0.69–0.89] 3.762.3
0.21 [0.12–0.30] — — 0.79 [0.69–0.87] 3,760.5
 Intimacy avoidance 415 254 0.25 0.17 0.15 [−0.14–0.45] — 0.10 [−0.16–0.35] 0.75 [0.66–0.85] 3.764.8
0.26 [0.17–0.35] — — 0.74 [0.65–0.83] 3,763.4
 Suspiciousness 415 254 0.24 0.14 0.25 [−0.21–0.71] 0.00 [−0.48–0.50] — 0.75 [0.65–0.85] 3.772.3
0.25 [0.16–0.35] — — 0.75 [0.66–0.84] 3,770.3
 Withdrawal 415 254 0.42 0.18 0.28 [−0.19–0.74] 0.14 [−0.32–0.64] — 0.57 [0.50–0.66] 3.717.0
0.42 [0.33–0.52] — — 0.58 [0.51–0.66] 3,715.3
Antagonism 415 254 0.35 0.09 0.00 [ 0.49–0.46] 0.36 [ 0.13–0.87] — 0.65 [0.56–0.73] 3,733.6
0.33 [0.24–0.43] — — 0.67 [0.58–0.75] 3.733.7
 Attention seeking 415 254 0.36 0.11 0.14 [−0.38–0.64] 0.21 [−0.31–0.75] — 0.65 [0.57–0.74] 3.739.7
0.34 [0.25–0.43] — — 0.66 [0.58–0.74] 3,738.3
 Callousnessa 415 254 0.23 −0.08 −0.57 [−1.08–0.06] — 0.79 [0.26–1.34] 0.77 [0.68–0.87] 3.772.6
0.18 [0.09–0.27] — — 0.82 [0.72–0.92] 3,779.2
 Deceitfulness 414 254 0.23 0.04 −0.09 [−0.59–0.39] 0.32 [−0.19–0.85] — 0.77 [0.67–0.87] 3.771.0
0.21 [0.12–0.30] — — 0.79 [0.69–0.89] 3,770.5
 Grandiositya 415 254 0.29 0.03 −0.19 [−0.68–0.28] — 0.49 [−0.01–1.00] 0.61 [0.70–0.80] 3.761.0
0.26 [0.17–0.36] — — 0.74 [0.64–0.83] 3,762.7
 Manipulativeness 415 254 0.31 0.06 −0.05 [−0.55–0.43] 0.35 [−0.15–0.88] — 0.70 [0.61–0.79] 3.750.0
0.28 [0.19–0.37] — — 0.72 [0.63–0.80] 3,749.8
Disinhibition 415 254 0.40 0.23 0.36 [0.10–0.64] — 0.04 [−0.20–0.27] 0.59 [0.52–0.68] 3.713.5
0.41 [0.32–0.50] — — 0.59 [0.52–0.67] 3,711.7
 Distractibility 415 254 0.39 0.20 0.36 [0.08–0.66] — 0.02 [−0.24–0.26] 0.62 [0.54–0.70] 3.729.1
0.38 [0.30–0.48] — — 0.62 [0.54–0.70] 3,727.2
 Impulsivity 415 254 0.26 0.17 0.21 [−0.08–0.50] — 0.06 [−0.18–0.30] 0.73 [0.64–0.83] 3.761.4
0.28 [0.19–0.37] — — 0.72 [0.64–0.81] 3,759.7
 Irresponsibility 415 254 0.22 0.06 −0.01 [−0.47–0.44] 0.25 [−0.23–0.75] — 0.76 [0.66–0.87] 3.781.2
0.22 [0.13–0.32] — — 0.78 [0.69–0.89] 3,780.2
 Rigid perfectionism 415 254 0.42 0.12 0.08 [−0.43–0.56] 0.34 [−0.15–0.87] — 0.59 [0.51–0.67] 3.723.7
0.40 [0.31–0.49] — — 0.60 [0.53–0.68] 3,723.5
 Risk taking 415 254 0.28 0.07 −0.01 [−0.52–0.48] 0.29 [−0.23–0.82] — 0.72 [0.63–0.81] 3.754.9
0.26 [0.17–0.35] — — 0.74 [0.64–0.82] 3,754.1
Psychoticism 415 254 0.28 0.14 0.26 [−0.23–0.74] 0.02 [−0.47–0.54] — 0.72 [0.63–0.82] 3.765.7
0.28 [0.19–0.37] — — 0.72 [0.64–0.81] 3,763.7
 Eccentricity 415 254 0.28 0.17 0.29 [0.01–0.59] — 0.00 [−0.24–0.23] 0.70 [0.61–0.80] 3.763.5
0.30 [0.21–0.40] — — 0.70 [0.62–0.80] 3,761.5
 Perceptual dysregulation 415 254 0.24 0.10 0.14 [−0.34–0.61] 0.11 [−0.38–0.62] — 0.75 [0.65–0.85] 3.767.5
0.24 [0.15–0.34] — — 0.76 [0.66–0.85] 3,765.7
 Unusual beliefs and experiences 415 254 0.16 0.03 −0.01 [−0.56–0.54] — 0.15 [−0.41–0.73] 0.85 [0.75–0.96] 3.791.8
0.14 [0.05–0.25] — — 0.86 [0.76–0.97] 3,790.0

Note. AMPD = alternative model for personality disorder; MZ pairs = number of monozygotic twin pairs; DZ pairs = number of dizygotic twin pairs; MZ ICC = monozygotic intraclass correlation, or the correlation on a given trait across MZ twin pairs; DZ ICC = dizygotic intraclass correlation; AIC = Akaike information criteria; A = additive genetic; D = dominant genetic; C = common environment; E = unique environment; CI = confidence intervals. Maximum likelihood 95% confidence intervals are displayed in brackets. Full ACE or ADE models are in the first row for each variable, followed by AE models. The bolded row is considered the best-fitting model, indicated by the lowest AIC.

a

AE model interpreted (and bolded) despite higher AIC because ADE model provided nonsensical parameters (i.e., negative variance components), perhaps due to lower than expected DZ ICCs. Models are estimated using direct symmetric approach, which does not place lower bound of 0 on variance components estimates to avoid upward bias in estimates, at the potential risk of decreasing interpretability (Verhulst et al., 2019).