Table.

Summary of studies included in review

Source	Sample	Symptoms included	Analysis	Main results
Dimensional studies of psychosis
Allardyce et al. [23]	n = 464 psychosis 1st episode	28 OPCRIT items	PFA	5 factors: mania, disorganization/bizarre, depression, nonbizarre/nonmood congruent delusions, auditory hallucinations
Bassett et al. [17]	n = 72 members (5 families) with broad-spectrum psychopathology	8 PANSS items and 1 item created—inappropriate affect	PCA	3 factors: (1) negative; (2) delusions/hallucinations, thought disorder, and inappropriate affect; (3) suspiciousness and stereotyped thinking
Bell et al. [38]	n = 146 SZ & SZA	30 PANSS items	PCA then CFA of present and Kay et al. [59] samples	PCA: 5 factors: negative, positive, cognitive, emotional discomfort, hostility CFA: Poor fit between 2 samples; although similar dimensions
Brekke et al. [37]	n = 193 SZ & SZA	11 BPRS items, 2 CAF items, 4 QLS items	CFA—goodness of fit assessed for 6 models	3-factor model best fit: positive, negative, disorganized
Bunk et al. [36]	n = 44 SZ, SZA, schizophreniform, affective illness	30 PANSS items at onset of illness then 42 y later	PCA at onset and follow-up	Onset: 5 factors: cognitive, social withdrawal, antisocial behavior, excitement, reality distortion Follow-up: 5 factors: excitement, cognitive/motor-restriction/rigidity, positive, negative, anxiety/depression
Cardno et al. [39]	n = 109 SZ or SZA sibling pairs	7 SANS/SAPS items 22 OPCRIT items	PCA	SANS/SAPS: 3 factors: disorganization, negative, positive OPCRIT: 4 factors: positive, disorganization, negative, 1st-rank delusions
Cardno et al. [24]	n = 224 psychosis twin pairs	18 OPCRIT items analyzed then 16 OPCRIT items	PCA of 18 items PCA of 16 items	18 items (psychotic symptoms): 6 factors: disorganized, negative, 1st-rank delusions, paranoid, other hallucinations, 1st-rank hallucinations 16 items (psychotic + affective symptoms): 3 factors: manic, general psychotic, depressive
Cuesta et al. [21]	n = 660 psychosis	64 AMDP items	PCA	10 factors: pure paranoid, mania, negative catatonia, depression, dysphoria, disorganization, Schneiderian, insight, psychomotor poverty, positive catatonia (hierarchical representation of factors)
Cuesta et al. [22]	n = 94 psychosis 1st episode	70 AMDP items	PCA	Hierarchical system with up to 10 factors: mania, disorganization/dysphoria, insight, depression, anxiety/guilt, psychomotor poverty, Schneiderian hallucinations, depersonalization/ derealization, other disorders of ego integrity, paranoid
Daneluzzo et al. [41]	n = 234 BP & SZ	3 PANSS scales 6 PANSS cluster scores	PCA of PANSS scales + clusters	PCA: SZ: 3 factors: positive, negative, depressive PCA: BP: 3 factors: positive, negative, mixed
Demjaha et al. [29]	n = 536 psychosis 1st episode	28 SCAN items	PAF	5 factors: mania, reality distortion, negative, depression, disorganization
Dikeos et al. [30]	n = 191 psychosis	51 OPCRIT items	PCA	5 factors: mania, reality distortion, depression, disorganization, negative
Ehmann et al. [33]	n = 165 psychosis	21 RAPP items	PCA	5 factors: aggression, positive, negative, organic/disorganization, anxiety/somatization
Kitamura et al. [26]	n = 584 psychosis	Semistructured interview	Factor analysis	5 factors: (1) manic, (2) depressive, (3) negative symptoms and formal thought disorder, (4) positive, (5) catatonic
McClellan et al. [42]	n = 69 SZ, BP, psychosis NOS (early-onset)	7 BPRS-C items 4 SAPS items 5 SANS items	PCA	4 factors: negative, positive, behavioral problems, dysphoria
McGorry et al. [52]	n = 509 psychosis 1st episode	92 RPMIP items	PAF	4 factors: mania, depression, Bleulerian (negative-disorganization), Schneiderian (positive)
McGrath et al. [31]	n = 1043 SZ, SZA	44 items from Diagnostic Checklist for DSM-IV	LCFA	5 factors: positive, affective, disorganized, negative, early onset/developmental
McIntosh et al. [54]	n = 204 psychosis	33 OPCRIT items	PCA performed separately at 4 consecutive inpatient admissions	4 factors: manic, depressive, disorganization, reality distortion (stable over time)
Minas et al. [16]	n = 114 psychosis	35 SAPS/SANS items	PCA	3 factors: negative, thought disorder, delusions/hallucinations
Peralta et al. [28]	n = 314 psychosis	11 AMDP items 8 SANS/SAPS global ratings	PCA AMDP PCA SANS/SAPS CFA SANS/SAPS	AMDP items: 3 factors: catatonic, manic, depressive SANS/SAPS: 3 factors: psychosis (positive), disorganization, negative CFA results support PCA results
Peralta et al. [20]	n = 660 psychosis	50 SAPS/SANS items	PCA 1st order then 2nd order	11 1st-order factors: poverty of affect/speech, thought disorder/inappropriate affect, bizarre delusions, social dysfunction, other delusions, paranoid delusions, bizarre behavior, non-auditory hallucinations, auditory hallucinations, manic thought disorder, attention 3 2nd-order factors: psychosis, disorganization, negative
Rapado-Castro et al. [43]	n = 99 psychosis 1st episode, early onset	30 PANSS items baseline, 4 wk, 6 mo	PCA at each time point	5 factors: positive, negative, depression, cognitive, hostility Dimensions stable over time but predominance differed: negative predominant baseline/4 wk; depression predominant at 6 mo
Ratakonda et al. [35]	n = 412 SZ & non-SZ	9 SAPS/SANS global ratings	PCA performed separately for SZ and non-SZ	3 factors similar for both SZ and non-SZ: positive, negative, disorganization
Rosenman et al. [25]	n = 978 psychosis	64 SCAN items	PFA	5 factors: dysphoria, positive, negative/incoherence, mania, substance abuse
Salvatore et al. [51]	n = 377 psychosis 1st episode	78 AMDP items 34 BSABS items	PCA	4 factors: pure mania with psychosis, depressive-excited mixed state, excited-hallucinatory-delusional state, disorganized-catatonic-autistic state
Serretti et al. [49]	n = 1004 SZ spectrum & mood disorder	38 OPCRIT items	PCA on half of sample CFA on other half	4 factors: excitement, depression, disorganization, delusion CFA showed good fit of model
Serretti et al. [50]	n = 2241 psychosis	46 OPCRIT items	PCA	4 factors: excitement, psychotic, depression, disorganization
Serretti et al. [27]	n = 1294 SZ, BP, delusional disorder	29 OPCRIT items	CFA of 6 factor models	5 factor best fit: positive, negative, depressive, manic, disorganized
Toomey et al. [19]	n = 630 psychoses global-level PCA n = 549 psychoses item-level PCA	9 SAPS/SANS global ratings 50 SAPS/SANS items	PCA on global ratings FA on global ratings then again separately on individual items	PCA: replicated 3 factors found in other studies: positive, negative, disorganization FA global ratings: 2 factors: positive (SAPS), negative (SANS) FA individual items: 5 factors: diminished expression, disorganization, disordered relating, bizarre delusions, auditory hallucinations
Toomey et al. [34]	n = 369 SZ, MDD, BP	9 SAPS/SANS global ratings	PCA performed separately for each diagnosis	SZ: 3 factors: negative, disorganization, positive MDD: 4 factors: diminished expression, diminished instrumental behavior, positive, disorganization BP: 2 factors: negative, positive MDD + BP: negative, positive, disorganization Psychotic (SZ + MDD + BP): 3 factors: negative, disorganization, positive Nonpsychotic (MDD + BP): 3 factors: (1) affective flattening/alogia/attention; (2) apathy/anhedonia/thought disorder; (3) disorganization
van Os et al. [18]	n = 166 psychosis recent onset	20 OCCPI items	PCA	7 factors: inappropriate-catatonia, delusions-hallucinations, mania, insidious-blunting, depression, lack of insight, paranoid delusions
van Os et al. [32]	n = 706 psychosis	65 CPRS items 46 OPCRIT items	PCA on CPRS then OPCRIT items	CPRS 4 factors: depressive, manic, negative, positive OPCRIT 5 factors: manic, depressive, negative, positive, disorganization
Ventura et al. [40]	n = 141 SZ, SZA, bipolar manic	18 BPRS items 24 BPRS items	PCA on 18 items then 24 items	18 item: 4 factors: negative, depression-anxiety, hostile-uncooperativeness, positive 24 item: 4 factors: manic-excitement, negative, positive, depression-anxiety
Wickham et al. [48]	n = 155 SZ, SZA, psychosis NOS (61 families)	53 OPCRIT items	PCA	5 factors: depressive, manic, reality distortion, disorganization, psychomotor poverty
Categorical studies of psychosis
Boks et al. [44]	n = 1056 psychosis (after examination, some proved not to be psychotic but left in analysis)	52 CASH items	EFA then CFA LCA of factor scores	5 factors: disorganization, negative, positive, depression, mania 6 classes: bipolar-schizomania, schizodepressive, hebephrenia, classic schizophrenia, non-psychotic, major depression
Derks et al. [46]	n = 4286 psychosis (SZ, SZA, BPI, BPII, BP NOS, MDD, healthy, other)	79 CASH items	EFA LCA of factor scores	EFA 5 factors: disorganization, negative, mania, positive, depression LCA 7 classes: schizophrenia, affective psychosis, manic-depression, deficit non-psychosis, depression, healthy, no symptoms
Kendler et al. [45]	n = 256 siblings w/ SZ n = 457 siblings with nonaffective psychoses	11 MSSS items + 2 additional variables: age at onset, sex	Factor analysis 11 MSSS items LCA of factor scores using 11 MSSS items, age at onset, and gender	3 factors SZ pairs: negative, positive, affective/manic 3 factors nonaffective pairs: negative, positive, affective/good prognosis LCA 5 classes: (1) SZA, (2) negative symptom SZ, (3) prominent delusions, flat affect, thought disorder SZ, (4) paranoid SZ, (5) remitting/relapsing catatonic SZ
Kendler et al. [63]	n = 343 SZ and affective disorders	21 items: 19 from OPCRIT, 2 items from MSSS	LCA	6 classes: classic schizophrenia, major depression, schizophreniform, bipolar-schizomania, schizodepression, hebephrenia
Peralta et al. [64]	n = 660 psychosis	16 MAS items	LCA	5 classes index episode: schizophrenia, psychosis, schizomania, schizodepression, cycloid 5 classes lifetime: schizophrenia, atypical schizophrenia, psychosis, schizobipolar, schizodepression
Studies comparing categorical vs. dimensional classification
Murray et al. [53]	n = 387 psychosis	62 OPCRIT items	PCA LCA	PCA: 4 factors: mania, reality distortion, depression, disorganization LCA: 4 classes: depression, disorganization, bipolar, reality distortion/depression
Peralta et al. [47]	n = 110 psychosis	12 subscale global ratings and inappropriate affect from CASH 3 time frames: index, lifetime, interepisode	LCA then factor analysis for each time frame	Index 4 classes: psychotic, mixed positive-negative, schizomanic, schizodepressive Lifetime 4 classes: mixed psychotic, psychotic, schizobipolar, schizodepressive Interepisode 3 classes: remitting psychosis, chronic psychosis, defect psychosis Index 4 factors: depression-motor poverty, negative, disorganization, psychosis Lifetime 4 factors: negative, mania, depression, psychosis Interepisode 3 factors: negative-disorganization, psychosis, depression-motor poverty

SZ, schizophrenia; SZA, schizoaffective; BPRS, Brief Psychiatric Rating Scale; CAF, Community Adjustment Form; QLS, Quality of Life Scale; AMDP, Manual for the Assessment and Documentation of Psychopathology; BP, bipolar; SCAN, Schedules for Clinical Assessment in Neuropsychiatry; PAF, principal axis factoring; RAPP, Routine Assessment of Patient Progress; RPMIP, Royal Park Multidiagnostic Instrument for Psychosis; PFA, principal factor analysis; LCFA, latent class factor analysis; BSABS, Bonn Scale for Assessment of Basic Symptoms; FA, factor analysis; MDD, major depressive disorder; CPRS, Comprehensive Psychopathological Rating Scale; CASH, Comprehensive Assessment of Symptoms and History; BPI, bipolar I; BPII, bipolar II; BP NOS, bipolar not otherwise specified; RMSEA, root mean square error of approximation; MSSS, Major Symptoms of Schizophrenia Scale; MAS, Manual for the Assessment of Schizophrenia.