Table 4 Fit indices and model comparisons of the non-social traits of autism (Adult Routines Inventory, Sensory Perception Quotient short, Autism Spectrum Quotient short)

Non-social model

1

Four-factor DSM-5 model

0.031

0.994

0.989

37.943**

2

One-factor non-social model

0.139

0.858

0.786

238.902**

3

Two-factor RMS and IS model A (restricted interests loading onto RMS factor)

0.090

0.944

0.910

100.910**

4

Two-factor RMS and IS model B (restricted interests loading onto IS factor)

0.107

0.921

0.872

137.767**

5

Three-factor model RMS, IS and restricted interests (RI) loading onto a separate factor

0.077

0.965

0.934

65.610**