Assessment Instruments For The Diagnosis Of Schizophrenia

Traditional psychological tests continue to be routinely applied in psychiatric settings to assess patients with a potential diagnosis of schizophrenia. The most widely used include questionnaires such as the Minnesota Multi-phasic Personality Inventory and projective tests such as the Rorschach test and the Thematic Apperception Test (TAT). The value of traditional tests in diagnosing schizophrenia in the absence of clinical findings has been questioned [108].

A considerable number of instruments have been constructed for the assessment of patients with schizophrenia or other psychotic disorders.

The ninth version of the Present State Examination [109] was used in the International Pilot Study of Schizophrenia or IPSS [20]. The PSE includes a considerable number of items for the assessment of psychotic signs and symptoms and provides detailed definitions for each item.

For close to 50 years the most popular and universally used psychiatric rating scale in the field of schizophrenia has been the Brief Psychiatric Rating Scale or BPRS [110], which continues to be used widely, although often under an expanded, or otherwise modified form.

A number of standardized, semi-structured as well as fully structured instruments have been developed to facilitate the collection of data on the basis of which it will be decided whether a patient meets the requirements specified in the criteria for a specified disorder. Over the years, the various instruments have been revised, and adapted to fit the criteria and algorithms of the latest versions of ICD-10 and DSM-IV.

Prominent among structured instruments are the Diagnostic Interview Schedule or DIS [111,112] and the Composite International Diagnostic Interview or CIDI [113,114]. Both the DIS and the CIDI are fully structured diagnostic interviews, which can be used by lay interviewers after proper training. They are intended for use in epidemiological studies in general populations. There are computer programs for the CIDI and the DIS that enable users to enter, clean, and score the interview. Both the DIS and the CIDI have a section which contains relevant questions to assess the presence or absence of each single criterion required for a diagnosis of schizophrenia in ICD-10 and DSM-IV. The inter-rater reliability of the instruments is quite high, also for those questions that are listed in the schizophrenia section. The concordance of CIDI and DIS positive or negative diagnoses made independently by clinicians is, however, far less perfect.

Prominent among semi-structured interviews are the SADS [99], the Structured Clinical Interview for DSM (III, III-R, IV) or SCID [115,116], the Schedules for Clinical Assessment in Neuropsychiatry or SCAN [117,118] and the International Personality Disorder Examination or IPDE [119,120]. All of these instruments have been field tested and were found to be reliable and applicable in different cultures.

The SADS was developed to facilitate the application of the Research Diagnostic Criteria or RDC. It exists in three different forms: SADS regular for the assessment of the present episode; SADS-L for the assessment of lifetime diagnoses; and SADS-C for the assessment of change.

The SCID is an instrument that was developed for the assessment of pathology and collection of data required for making diagnoses according to DSM criteria. It was first published for use with DSM-III, then revised for DSM-III-R, and finally for DSM-IV.

The SCAN is a set of instruments aimed at assessing, measuring and classifying the psychopathology and behaviour associated with the major psychiatric disorders of adult life, including schizophrenia and other psychotic disorders. It contains, in particular, the tenth version of the Present State Examination (PSE-10) and is accompanied by a comprehensive glossary. The SCAN yields diagnoses according to both ICD-10 and DSM-IV.

The IPDE assesses phenomenology relevant to the diagnosis of personality disorder according to ICD-10 and DSM-IV. It includes, in particular, items for the assessment of paranoid, schizoid and schizotypal personality disorder.

Various scales have been developed for rating specific individual aspects of schizophrenic symptomatology. For example, Andreasen [31] developed a scale for evaluating the presence of flattening of affect and inappropriate affect, and Chapman et al [25] have proposed an instrument for evaluating social as well as physical anhedonia.

Different scales have been proposed for the assessment of positive and negative symptoms in schizophrenia. The most prominent are the SANS [53,54], the SAPS [55] and the Positive and Negative Syndrome Scale or PANSS [121,122].

The SANS is a 25-item scale for the assessment of negative symptoms. The items may also be scored (from 0 to 5) on a summary sheet on which they are presented under five headings: affective flattening, alogia, avolition-apathy, anhedonia-asociality, and attentional impairment.

The SAPS is a 34-item scale for the assessment of positive symptoms. The items may also be scored (from 0 to 5) on a summary sheet on which they are presented under four headings: hallucinations, delusions, bizarre behaviour and positive formal thought disorder.

The PANSS is a 30-item instrument for assessing the prevalence of positive and negative syndromes in schizophrenia. It provides specific interview guidelines and assessment criteria, and includes two additional scales that consider positive and negative syndromes relative to one another and relative to general severity of psychopathology. Each item and each level of symptom severity are defined. The ratings provide summary scores on a seven-item positive score, seven-item negative scale, 16-item general psychopathology scale, and a composite (positive minus negative) index.

Unraveling Alzheimers Disease

Unraveling Alzheimers Disease

I leave absolutely nothing out! Everything that I learned about Alzheimer’s I share with you. This is the most comprehensive report on Alzheimer’s you will ever read. No stone is left unturned in this comprehensive report.

Get My Free Ebook

Post a comment