CLINICAL HANDBOOK OF SCHIZOPHRENIA

118 II. ASSESSMENT AND DIAGNOSISpositive symptoms are hallucinations (primarily hearing, but also tactile feelings, seeing,tasting, or smelling in the absence of environmental stimuli), delusions (false or patentlyabsurd beliefs that are not shared by others in the person’s environment), and disorganizationof thought and behavior (disconnected thoughts and strange or apparently purposelessbehavior). Some positive symptoms are considered highly specific, such as firstranksymptoms (e.g., delusions of thought insertion and auditory hallucinations with arunning commentary), and perhaps even pathognomonic (i.e., inappropriate affect). Formany people with schizophrenia, positive symptoms fluctuate in their intensity over timeand are episodic in nature, with approximately 20–40% experiencing persistent positivesymptoms (Curson, Patel, Liddle, & Barnes, 1988). Of note is that the term psychosisusually addresses delusions and hallucinations (Rudnick, 1997).Negative symptoms are the opposite of positive symptoms, in that they are definedby the absence of behaviors, cognitions, and emotions ordinarily present in persons withoutpsychiatric disorders. Common examples of negative symptoms include flat affect,avolition (lack of motivation to perform tasks), and alogia (diminished amount or contentof speech). All of these negative symptoms are relatively common in schizophrenia,and they tend to be stable over time. Furthermore, negative symptoms have a particularlydisruptive impact on the ability of people with schizophrenia to engage and to functionsocially, and to sustain independent living.The diagnosis of schizophrenia, according to DSM-IV-TR (American Psychiatric Association,2000), which is the most current diagnostic system in psychiatry, requires thefollowing criteria: (a) two or more characteristic symptoms, each present for a significantportion of time during a 1-month period (or less if successfully treated); (b) social/occupationaldysfunction; (c) persistence of the disturbance for at least 6 months, of which atleast 1 month must fully meet criterion a (active-phase symptoms). The other criteria excludeother psychiatric disorders, particularly schizoaffective disorder, mood disorders,substance use disorders, general medical condition, and pervasive developmental disorders(unless delusions and hallucinations exist, in which case schizophrenia can be diagnosedin conjunction with pervasive developmental disorders). There are various subtypesof schizophrenia (i.e., paranoid, disorganized, catatonic, undifferentiated, andresidual [American Psychiatric Association, 2000]), but their validity is not well established,and a patient can present with more than one of them over time.INTERVIEWING STRATEGIESThe current most widely accepted approach for diagnostic interviewing in psychiatric assessmentis the use of structured interviews. The main advantage of structured interviewsis that they provide a standardized approach for gathering information, which increasesthe (interrater) reliability of the assessment. Another advantage is that they provideguidelines for determining whether a specific symptom exists or not. On the downside, tobenefit fully from the advantages of structured interviews, a fair amount of training, aswell as ongoing fidelity evaluation, is required. A comprehensive assessment interviewshould commence with evaluation of basic characteristics of the disorder, followed by frequentlyassociated features and common comorbid diagnoses. In the following section wefocus on interviewing strategies for assessing characteristic symptoms of schizophrenia,recognizing that various assessment instruments can support a given interviewing strategy.A wide range of assessment instruments, divided primarily into self-report and interview-basedinstruments, have been developed to evaluate the existence and severity of