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Table 4 Twin-model fit statistics and parameter estimates

From: A longitudinal twin study of the association between childhood autistic traits and psychotic experiences in adolescence

 

Comparative fit with saturated model

Comparative fit with full ACE Cholesky

Model

−2LL

df

Par.

BIC

Δχ 2

Δdf

p

AIC

Δχ 2

Δdf

p

AIC

Autistic traits and anhedonia (five-variable decompositions)

Saturated

63,287.21

27,375

260

−158948.70

–

–

–

–

–

–

–

–

ACE sex diff.

63,489.32

27,535

100

−160045.50

202.11

160

<.05

−117.89

–

–

–

–

ACE const. a

63,619.71

27,580

55

−160280.40

332.50

205

<.001

−77.50

130.39

45

<.001

40.39

AE const.

63,784.42

27,595

40

−160237.50

497.20

220

<.001

57.20

164.71

15

<.001

134.71

CE const.

64,974.16

27,595

40

−159047.80

1686.94

220

<.001

1246.94

1345.45

15

<.001

1324.45

E const.

71,621.98

27,610

25

−152521.80

8334.77

235

<.001

7864.77

8002.27

30

<.001

7942.27

Autistic traits and parent-rated negative symptoms (five-variable decompositions)

Saturated

60,014.32

27,393

260

−162367.70

–

–

–

–

–

–

–

–

ACE sex diff.

60,189.54

27,553

100

−163491.40

175.22

160

.19

−144.78

–

–

–

–

ACE const. a

60,319.68

27,598

55

−163726.60

305.35

205

<.001

−104.65

130.13

45

<.001

40.13

AE

60,542.65

27,613

40

−163625.40

528.33

220

<.001

−7.02

222.98

15

<.001

192.98

CE

61,994.75

27,613

40

−162173.31

1980.42

220

<.001

1540.42

1675.07

15

<.001

1645.07

E

70,414.98

27,628

25

−153874.80

10400.66

235

<.001

9930.66

10095.31

30

<.001

10035.31

Parameter estimates from best-fitting decompositions

 

Autistic traits age 8

Autistic traits age 12

Autistic traits age 14

Autistic traits age 16

Variance specific to psychotic experiences

 

A1

C1

E1

A2

C2

E2

A3

C3

E3

A4

C4

E4

A5

C5

E5

Anhedonia

.02 (.00/.05)

.01 (.00/.05)

.00 (−.01/.01)

.00 (.00/.03)

.01 (.00/.04)

.00 (−.01/.01)

.02 (.00/.05)

.01 (.00/.04)

.00 (.00/.01)

.01 (.00/.05)

.00 (−.01/.03)

.02 (.00/.03)

.32 (.26/.36)

.00 (−.05/.06)

.58 (.55/.61)

Total

.03

.01

.03

.03

.90

Neg sym

.02 (.00/.04)

.10 (.04/.22)

.00 (.00/.01)

.01 (.00/.03)

.06 (.01/.17)

.00 (.00/.01)

.05 (.03/.10)

.00 (−.01/.01)

.01 (.00/.01)

.04 (.01/.07)

.00 (−.02/.02)

.02 (.01/.03)

.45 (.40/.50)

.10 (−.18/.18)

.14 (.13/.15)

Total

.12

.07

.06

.06

.69

  1. AE, CE, and E models are submodels within the ACE model that fit best. A1–A4, C1–C4, and E1–E4 are the paths shown in red in Fig. 1, and represent the influence of genetic and environmental causes of autistic traits on psychotic experiences, A5, C5, and E5 are residual pathways (shown in blue in Fig. 1), which represent the genetic and environmental influences on psychotic experiences that are independent of autistic traits
  2. Saturated saturated model of means and covariance, ACE sex diff. full ACE Cholesky decomposition, which included quantitative sex differences for all parameters, ACE const. constrained ACE Cholesky decomposition, with parameters fixed to be equal across sexes, −2LL fit statistic, df degrees of freedom, Par. parameters, AIC Akaike’s Information Criteria, BIC Bayesian Information Criteria, A additive genetic influences, C shared environmental influences, E nonshared environmental influences
  3. aIndicates best-fitting model
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Molecular Autism

ISSN: 2040-2392