Evidence based assessment/Schizophrenia (disorder portfolio)
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|Steps 1-2: Preparation phase|
|Steps 3-5: Prediction phase|
|Steps 6-9: Prescription phase|
|Steps 10-12: Process/progress/outcome phase|
For background information on what assessment portfolios are, click the link in the heading above.
Diagnostic Criteria for Schizophrenia
ICD-10 Diagnostic Criteria For schizophrenia, ICD-10 defines the criteria as:
General criteria for paranoid, hebephrenic, catatonic, and undifferentiated schizophrenia
Either at least one of the syndromes, symptoms, and signs listed under (1) below, or at least two of the symptoms and signs listed under (2) should be present for most of the time during an episode of psychotic illness lasting for at least 1 month (or at some time during most of the days).
(1) At least one of the following must be present: (a) thought echo, thought insertion or withdrawal, or thought broadcasting; (b) delusions of control, influence, of passivity, clearly referred to body or limb movements or specific thoughts, actions, or sensations; delusional perception; (c) hallucinatory voices giving a running commentary on the patient's behaviour, or discussing the patient among themselves, or other types of hallucinatory voices coming from some part of the body; (d) persistent delusions of other kinds that are culturally inappropriate and completely impossible (e.g. being able to control the weather, or being in communication with aliens from another world).
(2) Or at least two of the following: (a)persistent hallucinations in any modality, when occurring every day for at least 1 month, when accompanied by delusions (which may be fleeting or half-formed) without clear affective content, or when accompanied by persistent over-valued ideas (b)neologisms, breaks, or interpolations in the train of thought, resulting in incoherence or irrelevant speech; (c) catatonic behaviour, such as excitement posturing or waxy flexibility, negativism, mutism, and stupor; (d) "negative" symptoms, such as marked apathy, [paucity of speech, and blunting or incongruity of emotional responses (it must be clear that these are not due to depression or to neuroleptic medication).
Changes in DSM-5 The diagnostic criteria for depressive disorders changed slightly from DSM-IV to DSM-5. A summary is available here.
Base rates of schizophrenia in different populations and clinical settings
This section describes the demographic setting of the population(s) sampled, base rates of diagnosis, country/region sampled and the diagnostic method that was used. Using this information, clinicians will be able to anchor the rate of schizophrenia they are likely to see in their clinical practice.
- To find prevalence rates across multiple disorders, click here.
|Setting||Base Rate||Demography||Diagnostic Method||Best Recommended For|
|Non-institutionalized civilians||0.5%||48 contiguous US states||CIDI, SCID|
|Community sample||1.3%||Urban settings in 5 states (MD, NC, CN, CA, MO)||DIS|
|Inmates with severe mental disorders||23.5% incarcerated†, 69.7% hospitalized involuntarily†||All Federal Penitentiaries in Quebec-incarcerated and inmates currently hospitalized involuntarily||SCID|
|Patients presenting for inpatient and ambulatory services||
|General population (community, inpatient, and outpatient)||0.7%||Global – 44 countries||Clinical interview|
|General population||0.87%||Finland||CIDI, SCID|
|County Mental Health Service Users||54% - homeless individuals||San Diego County||Chart Diagnosis|
|Insurance claimants in 2002||Medicaid – 1.66%, Uninsured – 1.02%, Medicare – 0.83%, Privately insured – 0.13%, Veterans (through VA) – 1.41%||USA (Note: Medicaid rate was calculated using California Medi-Cal rates as a proxy)||Physician diagnosis|
†Rates reflect schizophrenia spectrum disorders. Note: DIS = Diagnostic Interview Schedule, CIDI = Composite International Diagnostic Interview, SCID = Structured Diagnostic Interview for DSM, BASIC-32 = Behavior and Symptoms Identification Scale
Search terms: [Schizophrenia] AND [prevalence OR incidence], [Schizophrenia] AND [Prevalence] AND [Outpatient OR inpatient] in PsycINFO, Medline, and PubMed
Screening instruments for schizophrenia
The following section contains a list of screening and diagnostic instruments for schizophrenia. The section includes administration information, psychometric data, and PDFs or links to the screenings. Screenings are used as part of the prediction phase of assessment; for more information on interpretation of this data, or how screenings fit in to the assessment process, click here.
Recommended screening instruments
|Screening Instrument||Format||Population||Administration Time||Resources|
|Psychiatric Diagnostic Screening Questionnaire (PDSQ)||Self-report, yes-or-no items||Ages 18+||15-20 minutes||-Available from Western Psychological Services|
|Structured Interview for Psychosis-Risk Syndrome (SIPS) ||Structured interview by a clinician or experienced rater||Pre-clinical adolescents and adults||2-3 hours||-Available from PRIME clinic at Yale University, contact Dr. Barbara Walsh at 203-974-7052|
|Bonn Scale for the Assessment of Basic Symptoms (BSABS)||Semi-structured interview by a clinician or experienced rater||Pre-clinical, residual, and at-risk adolescents and adults||2-3 hours||-Available from Amazon
-Available from publisher Shaker Verlag
Likelihood ratios and AUCs of screening measures for schizophrenia
- For a list of the likelihood ratios for more broadly reaching screening instruments, click here.
|Screening Measure (Primary Reference)||AUC||LR+ (Score)||LR- (Score)||Citation||Clinical generalizability||Download Link|
|Psychiatric Diagnostic Screening Questionnaire – PDSQ (Zimmerman & Mattia, 2001a)‡||.92 (N = 799)||2.7 (Subscale cutoff score = 1)||.33 (Subscale cutoff score = 1)||(Zimmerman & Sheeran, 2004)||Low – can distinguish psychotic disorders from non-psychotic disorders but cannot distinguish schizophrenia from other psychotic disorders (ex: MDD with psychosis)||Not free|
|Structured Interview for Prodromal Syndromes – SIPS (Miller et al., 1999)||Not given (N = 34)||3.5 (not given)||0 (not given)||(Miller et al., 2003)||Moderate – has some predictive validity (46% of those identified as prodromal by the SIPS developed schizophrenia psychosis within 6 mo.)||SIPS|
|Bonn Scale for the Assessment of basic Symptoms – BSABS (Gross, 1989)•
||(N = 160)
||Overall = 2.4 (>=1)
||Overall = 0.03 (>=1)
||(Klosterkotter, Hellmich, Steinmeyer, Schultze-Lutter, 2001)||Moderate – has some predictive validity for individuals who are in the prodromal period or suspected to be in the prodromal period of schizophrenia overall, cluster 1 has best predictive accuracy and may be most useful||Not found|
|Symptom Severity Scale of the DSM5||0.85 (N=314)||3.53||0.35||Ritsner, Mar, Arbitman, & Grinshpoon (2013)||Medium: Schizophrenia versus all other psychotic disorders, but has not been studied in a variety of populations with schizophrenia as it is a relatively new measure.||DSM 5 Scale|
|Positive and Negative Syndrome Scale (PANSS)
(Stanley, Flszbein, & Opfer, 1987)
|0.91 (N=314)||N/A||N/A||Ritsner, Mar, Arbitman, & Grinshpoon (2013)||Note: 45 minute clinical interview. Requires training. Attached to appendix.||Not free|
|NIMH: Diagnostic Interview Schedule – Psychotic Symptoms Scale
(Robins et al., 1981).
|N/A||4.4||1.7||Eaton et al. (1991)||Note: Quick self-report interview that screens for psychotic symptoms. Should be followed up with more indepth diagnostic assessments.||Not found|
|Royal Park Multi- Diagnostic Instrument for Psychosis (RPMIP) (McGorry, Copolov, & Singh (1990).||0.78 (N=200)||0.8||1.625||McGorry, McKenzie, & Jackson (2000)||Note: Interview that requires training.||Not found|
|Schizotypal Personality Questionnaire (SPQ) and Survey of Attitudes and Experiences (SAE)||0.74 (N=339)||1.76||0.59||Venables & Raine (2015)||Note: Samples included young, predominantly female samples of nonclinical controls.
Self-report measure, likelihood ratios are composite scores for three factors
(SAE not found)
|UCSD performance-based skills assessment (UPSA) in predicting independence||0.74 (N=434)||2.03||0.47||Mausbach et al. (2008)||Note: Two cut-off scores were suggested for predicting independent living in this population. These data are based on the cut-off score of 75 (greater sensitivity)||Not found|
Note: ‡ Used the SCID administered by trained raters. • Used Present State Examination 9 and psychiatrist diagnosis. (*) Cutoff score for all clusters was 15% of symptoms in that cluster present (for cluster 1= 5/35 symptoms)
- “LR+” refers to the change in likelihood ratio associated with a positive test score, and “LR-” is the likelihood ratio for a low score. Likelihood ratios of 1 indicate that the test result did not change impressions at all. LRs larger than 10 or smaller than .10 are frequently clinically decisive; 5 or .20 are helpful, and between 2.0 and .5 are small enough that they rarely result in clinically meaningful changes of formulation (Sackett et al., 2000).
Search terms: [schizophrenia] AND [sensitivity OR specificity] AND [differential diagnosis] AND [prodrome] in MedLine and PsycINFO
Interpreting schizophrenia screening measure scores
- For information on interpreting screening measure scores, click here.
Gold standard diagnostic interviews
For a list of broad reaching diagnostic interviews sortable by disorder with PDFs (if applicable), click here.
Recommended diagnostic interviews for schizophrenia
|Diagnostic Interview||Format||Population||Administration Time||Resources|
|Structured Clinical Interview for DSM-V (SCID)||Semi-structured interview to be administered by a clinician or an experienced rater||Adults
|Varies||-Available for purchase from APA Publishing (Note: Not free)
-Modified  (not most recent version, SCID-I)
-Located on Penn Lab, See Appendix 1 for schizophrenia modules
The following section contains a list of process and outcome measures for schizophrenia. The section includes benchmarks based on published norms and on mood samples for several outcome and severity measures, as well as information about commonly used process measures. Process and outcome measures are used as part of the process phase of assessment. For more information of differences between process and outcome measures, see the page on the process phase of assessment.
Severity and outcome
Clinically significant change benchmarks with common instruments for schizophrenia
|Measure||Scale||Cut Scores*|| Critical Change |
|Benchmarks Based on Published Norms for Samples with Schizophrenia|
| Positive and Negative Syndrome Scale
|PANSS Positive Scale||6||n/a||n/a||8.8||7.4||4.5|
|PANSS Negative Scale
|PANSS General Psychopathology Scale
| Scale for the Assessment of Positive Symptoms (SAPS) and Negative Symptoms (SANS)
| Satisfaction with Life Scale (SWLS)
| Cogtest Battery Composite Score
|Beck Depression Inventory||4||22||15||9||8||4.8|
|Overall Functioning: Global Assessment of Functioning (GAF)||26.8||81.6||54.8||8.3||7.0||4.2|
|Social Skills (Social Functioning Scale)||90.9||268.7||102.1||7.2||6.0||3.6|
Note: “A” = Away from the clinical range, “B” = Back into the nonclinical range, “C” = Closer to the nonclinical than clinical mean.
Note: Clinical significance may be limited for use in schizophrenia as the disorder is currently incurable and the extent to which a return to normal functioning may be less common. For this reason, some investigators have used methods other than those proposed by Jacobson and Truax (1991) to develop cut-off points (Jacobson et al. 1999).
- Example: Positive and Negative Syndrome Scale (PANSS) cut-off scores of 40, 45 and 50 have been mentioned for clinically significant change for schizophrenia patients in hospital settings (Schennach et al. 2015).
Search terms: [schizophrenia] AND [clinical significance OR outcomes OR change] AND [PANSS OR SWLS] in MedLine and PsycINFO
Cognitive behavioral therapy to routine care has shown limited evidence of an average effect size on psychosis symptoms. However, individual CBT is not widely available in the US, and group CBT is likely more cost-efficient. Other general treatment information can be found here.
- ICD-11 diagnostic criteria
- Find-a-Therapist (a curated list of find-a-therapist websites where you can find a provider)
- NIMH (information about schizophrenia)
- OMIM (Online Mendelian Inheritance in Man)
Online Support Group for Family Members & Individuals with Schizophrenia
Chatrooms for Individuals with Schizophrenia:
|Click here for references|