Clinical high-risk criteria of psychosis in 8–17-year-old community subjects and inpatients not suspected of developing psychosis

Table 1 Clinical high-risk criteria: (1) Ultra-high risk criteria in the definition of the criteria of psychosis-risk syndromes of the structured interview for Psychosis-Risk Syndromes, Structured Interview for Psychosis-Risk Syndromes[43] and (2) the basic symptom criteria in the definition of the Schizophrenia Proneness Instrument, Child and Youth version[44]

(1) Ultra-high risk criteria
Brief intermittent psychotic symptom (BIPS) syndrome
At least 1 of the following SIPS positive items scored 6 "severe and psychotic"
P1 Unusual thought content/delusional ideas
P2 Suspiciousness/persecutory ideas
P3 Grandiose ideas
P4 Perceptual abnormalities/hallucinations
P5 Disorganized communication
Symptoms reached a psychotic level of intensity in the past 3 mo
Present for at least several minutes per day at a frequency of at least once per month but less than required for rating of a conversion to psychosis, i.e., less than at least 1 h per day at an average frequency of 4 d/wk over 1 mo
Attenuated positive symptom (APS) syndrome
At least 1 of the 5 SIPS positive items (see above) scored 3 “moderate” to 5 “severe but not psychotic”
Symptoms have begun within the past year or currently rate one or more scale points higher compared to 12 mo ago
Symptoms have occurred at an average frequency of at least once per week in the past month
Genetic risk and functional deterioration syndrome
Patient meets criteria for schizotypal personality disorder according to SIPS
Patient has first-degree relative with a psychotic disorder
Patient has experienced at least 30% drop in the Global Assessment of Functioning score over the last month compared to 12 mo ago
[1 and 3] or [2 and 3] or all are met
(2) Basic symptom criteria
A general requirement for basic symptoms is that they deviate from what is considered the ‘normal’ self and, thus, have not always been present in the same severity
Cognitive–perceptive basic symptoms (COPER)
At least 1 of the following basic symptoms scored 3 “weekly occurrences” to 6 “daily occurrences” within the past 3 mo: thought interference; thought perseveration; thought pressure; thought blockages1; disturbance of receptive speech; decreased ability to discriminate between ideas and perception, fantasy and true memories; unstable ideas of reference; derealization; visual perception disturbances (excl. hypersensitivity to light or blurred vision); acoustic perception disturbances (excl. hypersensitivity to sounds); first occurrence ≥ 12 mo ago
Cognitive disturbances (COGDIS)
At least 2 of the following basic symptoms scored 3 “weekly occurrences” to 6 “daily occurrences” within the past 3 mo: inability to divide attention; thought interference; thought pressure; thought blockages1; disturbance of receptive speech; disturbance of expressive speech; unstable ideas of reference; disturbances of abstract thinking1; captivation of attention by details of the visual field

¹ Assessable only from age of 13 yr onwards.

Table 2 Sociodemographic and clinical characteristics of the sample (n = 539)

	Inpatients (n = 306)	Community subjects (n = 233)	Statistics; effect size
Age: mean ± SD (Median)	14.4 ± 2.5 (14.9)	13.0 ± 2.9 (12.9)	U = 26032.5, cP < 0.001: r = 0.231
Sex: n (%) male	133 (43.5)	102 (43.8)	χ² (1) = 0.013, P = 0.908; V = 0.005
Migration background1: n (%)	52 (17.0)	64 (27.5)	χ² (1) = 8.593, bP = 0.003; V = 0.126
Graduated from school: n (%)	28 (9.2)	15 (6.4)	χ² (1) = 1.326, P = 0.250; V = 0.050
Current school class (n = 491): mean ± SD	7.5 ± 2.5 (8)	6.2 ± 2.6 (6)	U = 20894.5, cP < 0.001; r = 0.253
Family history of psychotic disorder: n (%)	4 (1.3)	1 (0.4)	χ² (1) = 1.105, Pexact = 0.396, V = 0.045
Any lifetime nonpsychotic axis-I disorder2: n (%)	306 (100)	22 (9.4)	χ² (1) = 455.368, cP < 0.001; V = 0.919
Any present nonpsychotic axis-I disorder2: n (%)	306 (100)	13 (5.6)	χ² (1) = 488.187, cP < 0.001; V = 0.952
Number present axis-I disorders2: mean ± SD (Median)	1.5 ± 0.7 (1)	0.1 ± 0.3 (0)	U = 1499.5, cP < 0.001; r = 0.883
Any present depressive disorder: n (%)	55 (18.0)	0	χ² (1) = 46.638, cP < 0.001; V = 0.294
Any present manic episode3: n (%)	0	1 (0.4)	χ² (1) = 1.316, P = 0.251; V = 0.049
Any present anxiety disorder2: n (%)	68 (22.2)	2 (0.9)	χ² (1) = 53.426, cP < 0.001; V = 0.315
Any present obsessive–compulsive disorder: n (%)	35 (11.4)	1 (0.4)	χ² (1) = 25.720, cP < 0.001; V = 0.218
Any present adjustment disorder: n (%)	3 (1.0)	0	χ² (1) = 2.297, P = 0.262; V = 0.065
Any present eating disorder: n (%)	98 (32.0)	0	χ² (1) = 91.203, cP < 0.001; V = 0.411
Any present somatoform disorder: n (%)	4 (1.3)	0	χ² (1) = 3.069, P = 0.137; V = 0.075
Any present substance use disorder: n (%)	4 (1.3)	2 (0.9)	χ² (1) = 0.242, P = 0.623; V = 0.021
Any present tic disorder: n (%)	9 (2.9)	0	χ² (1) = 6.969, bP = 0.008; V = 0.114
Any present attention deficit hyperactivity disorder: n (%)	103 (33.7)	7 (3.0)	χ² (1) = 76.532, cP < 0.001; V = 0.377
Any present conduct disorder: n (%)	18 (5.9)	2 (0.9)	χ² (1) = 9.345, bP = 0.002; V = 0.132
Any present developmental disorder: n (%)	31 (10.1)	0	χ² (1) = 25.045, cP < 0.001; V = 0.216
Global Assessment of Functioning score (0-100): mean ± SD (Median)	52.3 ± 8.8 (53)	81.0 ± 10.0 (85)	U = 1516.0, cP < 0.001; r = 0.819
SOFAS (0-100): mean ± SD (Median)	60.0 ± 11.0 (60)	84.3 ± 7.9 (88)	U = 3001.5, cP < 0.001; r = 0.786

¹defined by first or second nationality other than the country of residence;

²does not include simple specific phobias of objects with little functional relevance but includes severe specific phobias such as school phobia;

³no participant met criteria of a bipolar disorder at baseline. SOFAS: Social and Occupational Functioning Assessment Scale[42]. V: Cramer’s V; r: Rosenthal’s r: 0.1 = weak effect; 0.3 = moderate effect; 0.5 = strong effect.

Table 3 Frequency of clinical high-risk criteria in the two groups (n = 539)

	Inpatients (n = 306)	Community subjects (n = 233)	χ² test; Cramer’s V
BIPS syndrome: n (%)	0	0	--
APS syndrome: n (%)	7 (2.3)	5 (2.1)	χ² (1) = 0.012; P = 0.912, V = 0.005
Genetic risk and functional decline syndrome: n (%)	2 (0.6)	0	χ² (1) = 1.529; Pexact = 0.508, V = 0.053
COGDIS: n (%)	10 (3.3)	4 (1.7)	χ² (1) = 1.258; P = 0.262, V = 0.048
COPER: n (%)	21 (6.9)	10 (4.3)	χ² (1) = 1.613; P = 0.204, V = 0.055
Any 1 of 5 CHR criteria: n (%)	29 (9.5)	17 (7.3)	χ² (1) = 0.806; P = 0.369, V = 0.039
Any 1 of 3 EPA criteria: n (%)	15 (4.9)	9 (3.9)	χ² (1) = 0.336; P = 0.562, V = 0.025
No CHR criterion: n (%)	277 (90.5)	216 (92.7)	χ² (7) = 5.676; P = 0.578, V = 0.103
Only genetic risk and functional decline: n (%)	2 (0.7)	0
Only COPER: n (%)	12 (3.9)	8 (3.4)
Only COGDIS: n (%)	2 (0.7)	2 (0.9)
COPER and COGDIS: n (%)	6 (2.0)	2 (0.9)
Only APS: n (%)	4 (1.3)	5 (2.1)
APS and COPER: n (%)	1 (0.3)	0
APS, COPER and COGDIS: n (%)	2 (0.7)	0

BIPS: Brief intermittent psychotic symptoms; APS: Attenuated psychotic symptoms; COGDIS: Cognitive Disturbances; COPER: Cognitive–Perceptive Basic Symptoms; EPA: European Psychiatric Association. V: Cramer’s V: 0.1 = weak effect; 0.3 = moderate effect; 0.5 = strong effect.

Table 4 Frequency of clinical high-risk criteria in the four diagnostic subsamples and the community sample (n = 539)

	ED (n = 97)	ADHD (n = 86)	AnxD and OCD (n = 94)	ASS (n = 29)	Community subjects (n = 233)	χ² test; Cramer’s V
APS syndrome: n (%)	4 (4.1)	0	3 (3.2)	0	5 (2.1)	χ² (4) = 4.632; P = 0.327, V = 0.093
Genetic risk and functional decline syndrome: n (%)	0	1 (1.2)	1 (1.1)	0	0	χ² (4) = 4.016; P = 0.404, V = 0.086
COGDIS: n (%)	4 (4.1)	2 (2.3)	4 (4.3)	0	4 (1.7)	χ² (4) = 3.427; P = 0.489, V = 0.080
COPER: n (%)	9 (9.3)	3 (3.5)	8 (8.5)	1 (3.4)	10 (4.3)	χ² (4) = 5.558; P = 0.235, V = 0.102
Any 1 of 5 CHR criteria: n (%)	11 (11.3)	5 (5.8)	12 (12.8)	1 (3.4)	17 (7.3)	χ² (4) = 5.369; P = 0.252, V = 0.100
Any 1 of 3 EPA criteria: n (%)	7 (7.2)	2 (2.3)	6 (6.4)	0	9 (3.9)	χ² (4) = 5.022; P = 0.285, V = 0.097
No CHR criterion: n (%)	86 (88.7)	81 (94.2)1	82 (87.2)	28 (96.6)	216 (92.7)	χ² (28) = 20.675; P = 0.839, V = 0.098
Only genetic risk and functional decline: n (%)	0	1 (1.2)	1 (1.1)	0	0
Only COPER: n (%)	4 (4.1)	2 (2.3)	5 (5.3)	1 (3.4)	8 (3.4) 1
Only COGDIS: n (%)	0	1 (1.2) 1	1 (1.1)	0	2 (0.9)
COPER and COGDIS: n (%)	3 (3.1)	1 (1.2)	2 (2.1)	0	2 (0.9)
Only APS: n (%)	2 (2.1)	0	2 (2.1)	0	5 (2.1)
APS and COPER: n (%)	1 (1.0)	0	0	0	0
APS, COPER and COGDIS: n (%)	1 (1.0)	0	1 (1.1)1	0	0

¹Indicates that 1 subject of this category converted to psychosis within 2 years. No brief intermittent psychotic symptoms (BIPS) criteria met. ED: Eating disorder; ADHD: attention-deficit hyperactivity disorder; AnxD and OCD: anxiety disorder, including obsessive-compulsive disorder; ASS: Asperger’s syndrome; APS: attenuated psychotic symptoms; COGDIS: Cognitive Disturbances; COPER: Cognitive-Perceptive Basic Symptoms: EPA: European Psychiatric Association; CHR: Clinical high-risk. V: Cramer’s V: 0.1 = weak effect; 0.3 = moderate effect; 0.5 = strong effect.

Table 5 Frequency of criteria-relevant basic symptoms in the four diagnostic subsamples and the community sample (n = 539)

	ED (n = 97)	ADHD (n = 86)	AnxD and OCD (n = 94)	ASS (n = 29)	Community subjects (n = 233)	χ² test; Cramer’s V
Inability to divide attention: n (%)	1 (1.0)	0	2 (2.1)	0	0	χ² (4) = 6.534; P = 0.163, V = 0.101
Captivation of attention: n (%)	0	0	1 (1.1)	2 (6.9)	4 (1.7)	χ² (4) = 9.855; aP = 0.043, V = 0.135
Disturbance of abstract thinking1: n (%)	0	0	0	0	2 (1.3)	χ² (4) = 3.129; P = 0.536, V = 0.088
Disturbance of expressive speech: n (%)	5 (5.2)	3 (3.5)	5 (5.3)	2 (6.9)	15 (5.6)	χ² (4) = 0.752; P = 0.945, V = 0.037
Disturbance of receptive speech: n (%)	1 (1.0)	1 (1.2)	3 (3.2)	0	1 (0.4)	χ² (4) = 5.013; P = 0.286, V = 0.096
Thought interference: n (%)	2 (2.0)	1 (1.2)	3 (3.2)	3 (10.3)	5 (2.1)	χ² (4) = 8.009; P = 0.091, V = 0.122
Thought blockages1: n (%)	9 (10.0)	5 (11.1)	8 (9.2)	2 (9.1)	13 (8.3)	χ² (4) = 0.403; P = 0.982, V = 0.032
Thought pressure: n (%)	8 (8.2)	4 (4.7)	11 (11.7)	3 (10.3)	7 (3.0)	χ² (4) = 11.019; aP = 0.026, V = 0.143
Unstable ideas of reference: n (%)	3 (3.1)	0	1 (1.1)	0	1 (0.4)	χ² (4) = 6.673; P = 0.154, V = 0.111
Thought perseveration: n (%)	0	2 (2.3)	3 (3.2)	1 (3.4)	3 (1.3)	χ² (4) = 3.964; P = 0.411, V = 0.086
Impaired discrimination between true memories and phantasy: n (%)	1 (1.0)	1 (1.2)	6 (6.4)	0	7 (3.0)	χ² (4) = 7.310; P = 0.120, V = 0.116
Derealization: n (%)	17 (17.5)	2 (2.3)	14 (14.9)	2 (6.9)	6 (2.6)	χ² (4) = 32.380; cP < 0.001, V = 0.245
Visual perception disturbances: n (%)	13 (13.4)	7 (8.1)	10 (10.6)	5 (17.2)	11 (4.7)	χ² (4) = 10.652; aP = 0.031, V = 0.141
Acoustic perception disturbances: n (%)	12 (12.4)	6 (7.1)	10 (10.6)	2 (6.9)	17 (7.3)	χ² (4) = 3.063; P = 0.547, V = 0.075

¹Assessable only from age of 13 years onwards, thus only calculated on n = 404. ED: Eating disorder; ADHD: Attention-deficit hyperactivity disorder; AnxD and OCD: anxiety disorder, including obsessive-compulsive disorder; ASS: Asperger’s syndrome. In bold, cells with standardized residuals ≥ |1.96|. This equals significant deviation from the expected cell frequency. V: Cramer’s V: 0.1 = weak effect; 0.3 = moderate effect; 0.5 = strong effect.

Table 6 Frequency of brief intermittent and attenuated psychotic symptoms in the four diagnostic subsamples and the community sample (n = 539)

	ED (n = 97)	ADHD (n = 86)	AnxD and OCD (n = 94)	ASS (n = 29)	Community subjects (n = 233)	χ² test; Cramer’s V
P1: Unusual thought content/delusional ideas: n(%)	6 (6.2)	4 (4.7)	14 (14.9)1	4 (13.8)	13 (5.6)	χ² (4) = 11.391; aP = 0.023, V = 0.145
P2: Suspiciousness/persecutory ideas: n(%)	2 (2.1)	1 (1.2)	4 (4.3)	3 (10.3)2	4 (1.7)	χ² (4) = 9.425; P = 0.051, V = 0.132
P3: Grandiose ideas: n(%)	0	0	0	0	1 (0.4)	χ² (4) = 1.316; P = 0.859, V = 0.049
P4: Perceptual abnormalities/hallucinations: n(%)	14 (14.2)	20 (23.3)	22 (23.4)	8 (27.6)	54 (23.2)	χ² (4) = 4.150; P = 0.368, V = 0.088
P5: Disorganized communication: n(%)	0	0	0	0	1 (0.4)	χ² (4) = 1.316; P = 0.859, V = 0.049

¹most frequent in AnxD and OCD: thought insertion and broadcasting; unusual, somatic and nihilistic idea;

²most frequent in ASS: ideas of being redlined or observed (common rating). In bold, cells with standard residuals ≥ |1.96|. This equals a significant deviation (less or more) from the expected cell frequency. ED: Eating disorder; ADHD: Attention-deficit hyperactivity disorder; AnxD and OCD: Anxiety disorder, including obsessive-compulsive disorder; ASS: Asperger’s syndrome. V: Cramer’s V: 0.1 = weak effect; 0.3 = moderate effect; 0.5 = strong effect.

Table 7 Severity of clinical high-risk criteria and symptoms (mean SD, median) in inpatients and the community sample (n = 539)

	Inpatients (n = 306)	Community subjects (n = 233)	Mann–Whitney U; Rosenthal’s r
Sum score of SIPS positive items	2.5 ± 2.5, 2	2.1 ± 2.3, 1	Z = -1.852, P = 0.064; r = 0.080
Sum score of 9 basic symptoms of COGDIS	0.8 ± 2.5, 0	0.4 ± 1.2, 0	Z = -1.125, P = 0.260, r = 0.048
Sum score of 10 basic symptoms of COPER	1.6 ± 3.6, 0	0.6 ± 1.7, 0	Z = -3.852, cP < 0.001; r = 0.166
P1: Unusual thought content / delusional ideas	0.9 ± 1.0, 1	0.8 ± 0.9, 1	Z = -1.341, P = 0.180; r = 0.058
P2: Suspiciousness / persecutory ideas	0.4 ± 0.8, 0	0.2 ± 0.6, 0	Z = -4.281, cP < 0.001; r = 0.184
P3: Grandiose ideas	0.1 ± 0.3, 0	0.1 ± 0.4, 0	Z = -0.426, P = 0.670; r = 0.018
P4: Perceptual abnormalities / hallucinations	1.0 ± 1.4, 0	1.0 ± 1.2, 0	Z = -1.119, P = 0.263; r = 0.048
P5: Disorganized communication	0.1 ± 0.3, 0	0.1 ± 0.3, 0	Z = -0.397, P = 0.691; r = 0.017
Inability to divide attention	0.1 ± 0.5, 0	0	Z = -1.514, P = 0.130; r = 0.065
Captivation of attention	0.0 ± 0.2, 0	0.0 ± 0.3, 0	Z = -0.757, P = 0.449; r = 0.033
Disturbance of expressive speech	0.2 ± 0.8, 0	0.1 ± 0.4, 0	Z = -0.268, P = 0.789; r = 0.012
Disturbance of abstract thinking1	0	0.0 ± 0.1, 0	Z = -1.622, P = 0.105; r = 0.070
Thought interference	0.1 ± 0.6, 0	0.1 ± 0.4, 0	Z = -0.591, P = 0.555; r = 0.025
Thought blockages1	0.2 ± 0.8, 0	0.1 ± 0.6, 0	Z = -1.044, P = 0.297; r = 0.045
Thought pressure	0.2 ± 0.9, 0	0.1 ± 0.5, 0	Z = -2.639, bP = 0.008; r = 0.114
Disturbance of receptive speech	0.0 ± 0.3, 0	0.0 ± 0.1, 0	Z = -1.324, P = 0.185; r = 0.057
Unstable ideas of reference	0.0 ± 0.2, 0	0.0 ± 0.2, 0	Z = -1.046, P = 0.296; r = 0.045
Impaired discrimination between ideas/true memories and phantasy	0.1 ± 0.6, 0	0.0 ± 0.3, 0	Z = -0.230, P = 0.818; r = 0.010
Thought perseveration	0.0 ± 0.3, 0	0.0 ± 0.2, 0	Z = -0.607, P = 0.544; r = 0.026
Derealization	0.4 ± 1,1, 0	0.0 ± 0.2, 0	Z = -3.924, cP < 0.001.; r = 0.169
Visual perception disturbances	0.3 ± 1.1, 0	0.1 ± 0.4, 0	Z = -2.822, bP = 0.005; r = 0.122
Acoustic perception disturbances	0.2 ± 0.9, 0	0.2 ± 0.8, 0	Z = -1.014, P = 0.311; r = 0.044

¹Assessable only from age of 13 years onwards, thus only calculated on n = 404.

r: Rosenthal’s r: 0.1 = weak effect; 0.3 = moderate effect; 0.5 = strong effect.

Table 8 Severity of clinical high-risk criteria and symptoms (mean ± SD, median) in the four diagnostic subsamples and the community sample (N = 539)

	ED (n = 97)	ADHD (n = 86)	AnxD and OCD (n = 94)	ASS (n = 29)	Community subjects (n = 233)	Kruskal–Wallis (results of posthoc Mann–Whitney tests)
Sum score of SIPS positive items	2.1 ± 2.4, 1	2.0 ± 2.1, 1	3.1 ± 2.6, 2	3.3 ± 3.3, 2	2.1 ± 2.3, 1	χ² (4) = 18.866, cP = 0.001 (AnxD and OCD>ED = ADHD = GPS)
Sum score of COGDIS	0.8 ± 2.1, 0	0.5 ± 1.7, 0	1.2 ± 3.5, 0	0.7 ± 1.7, 0	0.4 ± 1.2, 0	χ² (4) = 7.692, P = 0.104
Sum score of COPER	1.8 ± 3.6, 0	1.1 ± 3.3, 0	2.2 ± 4.2, 0	1.1 ± 1.7, 0	0.6 ± 1.7, 0	χ² (4) = 26.988, cP < 0.001 (ED = AnxD and OCD = ASS > GPS; AnxD and OCD = ED > ADHD)
P1: Unusual thought content	0.8 ± 0.9, 1	0.7 ± 0.9, 1	1.2 ± 1.1, 1	1.2 ± 1.3, 1	0.8 ± 0.9, 1	χ² (4) = 12.397, aP = 0.015 (AnxD and OCD > ED = ADHD = GPS)
P2: Suspicious-ness/persecutory ideas	0.4 ± 0.8, 0	0.2 ± 0.6, 0	0.5 ± 0.9, 0	0.7 ± 1.1, 0	0.2 ± 0.6, 0	χ² (4) = 30.502, cP < 0.001 (ASS = AnxD and OCD = ED > GPS; AnxD and OCD = ASS > ADHD)
P3: Grandiose ideas	0.1 ± 0.3, 0	0.1 ± 0.2, 0	0.2 ± 0.5, 0	0.1 ± 0.3, 0	0.1 ± 0.4, 0	χ² (4) = 4.029, P = 0.402
P4: Perceptual abnormalities	0.8 ± 1.3, 0	1.0 ± 1.5, 0	1.2 ± 1.4, 1	1.3 ± 1.6, 1	1.0 ± 1.2, 0	χ² (4) = 6.391, P = 0.172
P5: Disorganized communication	0.0 ± 0.2, 0	0.0 ± 0.2, 0	0.1 ± 0.4, 0	0.1 ± 0.3, 0	0.1 ± 0.3, 0	χ² (4) = 3.129, P = 0.539
Inability to divide attention	0.0 ± 0.4, 0	0	0.1 ± 0.9, 0	0	0	χ² (4) = 6.537, P = 0.163
Captivation of attention	0	0	0.0 ± 0.2, 0	0.1 ± 0.4, 0	0.0 ± 0.3, 0	χ² (4) = 9.749, aP = 0.045 (ASS > ED = ADHD)
Disturbance of expressive speech	0.2 ± 0.9, 0	0.1 ± 0.6, 0	0.2 ± 1.0, 0	0.1 ± 0.4, 0	0.1 ± 0.4, 0	χ² (4) = 0.675, P = 0.954
Disturbance of abstract thinking1	0	0	0	0	0.0 ± 0.1, 0	χ² (4) = 2.632, P = 0.621
Thought interference	0.1 ± 0.5, 0	0.1 ± 0.5, 0	0.1 ± 0.6, 0	0.3 ± 1.0, 0	0.1 ± 0.4, 0	χ² (4) = 7.912, P = 0.095
Thought blockages1	0.2 ± 0.8, 0	0.2 ± 0.9, 0	0.3 ± 1.0, 0	0.1 ± 0.4, 0	0.1 ± 0.6, 0	χ² (4) = 2.048, P = 0.727
Thought pressure	0.3 ± 0.9, 0	0.1 ± 0.6, 0	0.4 ± 1.2, 0	0.1 ± 0.4, 0	0.1 ± 0.5, 0	χ² (4) = 10.944, aP = 0.027 (ED = AnxD and OCD > GPS)
Disturbance of receptive speech	0.0 ± 0.1, 0	0.0 ± 0.2, 0	0.1 ± 0.5, 0	0	0.0 ± 0.07, 0	χ² (4) = 5.047, P = 0. 283
Unstable ideas of reference	0.1 ± 0.3, 0	0	0.0 ± 0.1, 0	0	0.0 ± 0.2, 0	χ² (4) = 6.643, P = 0.156
Impaired discrimination between	0.0 ± 0.3, 0	0.1 ± 0.7, 0	0.2 ± 0.7, 0	0	0.0 ± 0.3, 0	χ² (4) = 7.344, P = 0.119
Thought perseveration	0	0.1 ± 0.4, 0	0.1 ± 0.4, 0	0.0 ± 0.1, 0	0.0 ± 0.2, 0	χ² (4) = 3.954, P = 0.412
Derealization	0.4 ± 1.1, 0	0.1 ± 0.7, 0	0.6 ± 1.5, 0	0.2 ± 0.7, 0	0.0 ± 0.2, 0	χ² (4) = 32.930, cP < 0.001 (ED = AnxD and OCD > ADHD = GPS)
Visual perception disturbances	0.4 ± 1.2, 0	0.3 ± 1.2, 0	0.3 ± 1.0, 0	0.3 ± 0.7, 0	0.1 ± 0.4, 0	χ² (4) = 10.764, aP = 0.029 (ED = AnxD and OCD = ASS > GPS)
Acoustic perception disturbances	0.3 ± 1.0, 0	0.2 ± 0.7, 0	0.3 ± 1.0, 0	0.1 ± 0.3, 0	0.2 ± 0.8, 0	χ² (4) = 3.227, P = 0.521

¹assessable only from age of 13 years onwards, thus only calculated on n = 404. ED: Eating disorder; ADHD: Attention-deficit hyperactivity disorder; AnxD and OCD: Anxiety disorder, including obsessive-compulsive disorder; ASS: Asperger’s syndrome; GPS: community subjects.