Schizophrenia Research

Issues in diagnosis and classification: Good reliability:

• Good inter-rater reliability and good test-retest reliability

• Osorio et al. => report excellent reliability for the diagnosis of SZ in 180 individuals using the DSM-5

• Pairs of interviewers achieved inter-rater reliability of +97 and test-retest of +92

Issues in diagnosis and classification: Low reliability

• Low inter-rater reliability

• Santelmann et al. => conducted a meta-analysis of 25 studies with patients diagnosed by different raters and found that reliability of SZ diagnosis had consistently lower inter-rater reliability than the diagnosis of major depressive disorder and bi-polar disorder

Issues in diagnosis and classification: Low validity

• Low criterion validity

• Cheniaux et al. => had 2 psychiatrists independently assess the same 100 clients using ICD-10 and DSM criteria and found that 68 were diagnosed with SZ under the ICD system and 39 under DSM

• Suggests that schizophrenia is either over-or underdiagnosed according to the diagnostic system

• Suggests criterion validity is low

Issues in diagnosis and classification: Counterpoint to low validity (potentially good criterion validity)

• Osorio et al. => excellent agreement between clinicians when they used 2 measures to diagnose SZ both derived from the DSM system

• Means that criterion validity for diagnosing SZ is actually good provided it takes place within a single diagnostic system

Issues in diagnosis and classification: Co-morbidity

• Buckley et al. => found that with people with SZ, 50% were also diagnosed with depression

• Symptoms could actually reflect other conditions (e.g. depression)

• Challenges descriptive validity of SZ as it may not be a single, clearly defined condition

Issues in diagnosis and classification: Symptom overlap

• Newson et al. => conducted a meta-analysis

• Found significant symptom overlap across different DSM-5 disorder categories where criteria do not sufficiently distinguish between SZ symptoms and those of overlapping disorders like depression

Issues in diagnosis and classification: Gender bias

• Hambrecht et al.

• Found that males and females are equally at risk of developing SZ but it is underdiagnosed in women

• Means women may not be receiving treatment that might benefit them

Issues in diagnosis and classification: Culture bias

• Schwartz et al.

• Found evidence that African Americans are 2.4 times more likely to be diagnosed with SZ compared with non-African American individuals

• Can lead to stigma + discrimination