. Author manuscript; available in PMC: 2010 Mar 24.

Published in final edited form as: Psychol Assess. 2008 Sep;20(3):206–216. doi: 10.1037/a0012764

Table 5. DSM–IV Generalized Anxiety Disorder Item-by-Item Tests for Effects of Study on Thresholds.

Model	−2LnL	Δχ²	Δdf	AIC	Study effect
Study on latent mean (baseline)	14,244.44			−14,569.56
Item free
Did your muscles often feel tense, sore or achy?	14,235.31	9.12^**	1	−14,576.69	.20
Did you often tire easily?	14,239.15	5.29^*	1	−14,572.85	−.16
Were you so nervous you had trouble concentrating?	14,225.04	19.40^***	1	−14,586.96	−.31
Did you often have trouble falling asleep?	14,238.60	5.84^*	1	−14,573.40	−.17
Were you often irritable or especially impatient?	14,213.21	31.22^***	1	−14,598.79	.40
Did you feel restless or keyed up and on edge?	14,235.86	8.57^**	1	−14,576.14	.28

Note. N = 6,426. The most parsimonious model is shown in boldface. DSM–IV = Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; AIC = Akaike information criterion.

p < .05.

^**

p < .01.

^***

p < .001.