Table 3.

Extremes analysis

		Cut-off Level
	>85%	>90%	>95%
Paranoia
Co-twin means
MZ	.48 (N=561)	.44 (N=367)	.42 (N=178)
DZ	.27 (N=495)	.22 (N=312)	.22 (N=156)
Proband Concordances
MZ	.44	.32	.26
DZ	.30	.23	.18
Tetrachoric correlations
MZ	.56 (.47-.63)	.47 (.36-.56)	.53 (.39-.65)
DZ	.34 (.24-.43)	.33 (.20-.47)	.38 (.21-.54)
DF Extremes
hg2	.42 (.24-.60)	.43 (.24-.61)	.41 (.20-.62)
cg2	.05 (−.09-.20)	.01 (−.13-.16)	.01 (−.16-.18)
LT estimates
h2	.44 (.19-.63)	.27 (.00-.55)	.27 (.00-.63)
c2	.12 (.00-.33)	.20 (.00-.45)	.25 (.00-.54)
e2	.45 (.37-.53)	.53 (.44-.64)	.48 (.36-.62)
Hallucinations
Co-twin means
MZ	.45 (N=546)	.40 (N=383)	.38 (N=188)
DZ	.31 (N=493)	.27 (N=325)	.28 (N=167)
Proband Concordances
MZ	.41	.32	.26
DZ	.33	.27	.20
Tetrachoric correlations
MZ	.52 (.44-.60)	.47 (.36-.56)	.50 (.35-.62)
DZ	.39 (.29-.48)	.38 (.29-.49)	.41 (.25-.56)
DF Extremes
hg2	.21 (.07-.40)	.22 (.04-.39)	.19 (−.03-.40)
cg2	.17 (−.25-.40)	.15 (−.21-.37)	.17 (−.24-.42)
LT estimates
h2	.27 (.02-.52)	.15 (.00-.45)	.15 (.00-.55)
c2	.25 (.04-.46)	.32 (.06-.50)	.35 (.01-.55)
e2	.48 (.40-.56)	.54 (.44-.64)	.51 (.38-.63)
Cognitive
Disorganisation
Co-Twin means
MZ	.43 (N=681)	.34 (N=455)	.26 (N=258)
DZ	.33 (N=670)	.27 (N=431)	.18 (N=251)
Proband Concordances
MZ	.43	.34	.23
DZ	.33	.27	.18
Tetrachoric correlations
MZ	.46 (.39-.54)	.44 (.34-.53)	.37 (.24-.50)
DZ	.24 (.14-.33)	.30 (.19-.41)	.26 (.12-.41)
DF Extremes
hg2	.33 (.18-.49)	.30 (.13-.46)	.33 (.14-.52)
cg2	.10 (−.02-.22)	.13 (−.00-.26)	.06 (−.10-.21)
LT estimates
h2	.45 (.23-.54)	.29 (.01-.53)	.22 (.00-.51)
c2	.00 (.00-.20)	.15 (.00-.38)	.16 (.00-.40)
e2	.53 (.46-.55)	.55 (.47-.65)	.62 (.50-.76)
Grandiosity
Co-twin means
MZ	.50 (N=571)	.49 (N=346)	.48 (N=214)
DZ	.25 (N=483)	.26 (N=377)	.27 (N=182)
Proband Concordances
MZ	.48	.39	.32
DZ	.29	.25	.18
Tetrachoric correlations
MZ	.62 (.55-.69)	.60 (.51-.68)	.57 (.45-.67)
DZ	.30 (.20-.42)	.32 (.21-.43)	.34 (.18-.49)
DF Extremes
hg2	.51 (.33-.68)	.46 (.28-.65)	.41 (.21-.61)
cg2	−.01 (−.15-.13)	.07 (−.11-.17)	.08 (−.10-.22)
LT estimates
h2	.62 (.37-.68)	.58 (.29-.68)	.44 (.05-.67)
c2	.00 (.00-.21)	.02 (.00-.25)	.13 (.00-.45)
e2	.38 (.32-.46)	.40 (.32-.49)	.44 (.33-.56
Anhedonia
Co-twin means
MZ	.50 (N=514)	.49 (N=295)	.46 (N=202)
DZ	.29 (N=546)	.29 (N=277)	.30 (N=192)
Proband Concordances
MZ	.42	.49	.27
DZ	.32	.26	.18
Tetrachoric correlations
MZ	.54 (.45-.61)	.51 (.40-.61)	.48 (.34-.60)
DZ	.29 (.16-.42)	.29 (.16-.42)	.28 (.11-.44)
DF Extremes
hg2	.41 (.24-.57)	.36 (.17-.55)	.32 (.11-.54)
cg2	.09 (−.04-.23)	.11 (.00-.26)	.13 (−.04-.30)
LT estimates
h2	.51 (.25-.62)	.42 (.08-.61)	.41 (.00-.60)
c2	.04 (.00-.25)	.08 (.00-.61)	.07 (.00-.42)
e2	.46 (.38-.54)	.49 (.39-.61)	.52 (.40-.66)
Negative symptoms
Co-twin means
MZ	.80 (N=578)	.81 (N=433)	.77 (N=199)
DZ	.50 (N=525)	.44 (N=327)	.41 (N=175)
Proband Concordances
MZ	.73	.73	.61
DZ	.51	.39	.30
Tetrachoric correlations
MZ	.91 (.88-.94)	.91 (.88-.94)	.86 (.80-.91)
DZ	.60 (.51-.69)	.60 (.51-.69)	.57 (.44-.69)
DF Extremes
hg2	.62 (.43-.81)	.74 (.55-.94)	.71 (.49-.93)
cg2	.19 (.03-.35)	.07 (−.09-.23)	.06 (−.12-.23)
LT estimates
h2	.44 (.30-.60)	.59 (.41-.79)	.58 (.33-.87)
c2	.45 (.31-.58)	.32 (.13-.49)	.28 (.01-.51)
e2	.11 (.08-.14)	.09 (.06-.12)	.14 (.09-.20)

Note. MZ=monozygotic, DZ=dizygotic, DF=DeFries-Faulker, hg²=group heritability, cg²=group shared environmental influences, LT=Liability threshold, h²=heritability estimate, c²=shared environmental estimate, e²=non-shared environmental estimate