classifications

Question 1

✅ Diagnosis had high reliability when using the same diagnostic instrument.

Answer 1

• Osorio et al. (2019) evaluated the diagnosis of schizophrenia using the DSM-5 and showed excellent inter-rater reliability, with a kappa score of 0.97.
• This demonstrates that when psychiatrists apply standardized diagnostic criteria consistently, such as the DSM-5, they can reliably identify schizophrenia across different cases. High reliability is essential because accurate and consistent diagnosis ensures patients receive appropriate treatment, which can improve prognosis and quality of life.
• However, while reliability is high with the DSM-5, it does not guarantee validity; psychiatrists may agree on a diagnosis that still fails to accurately reflect the underlying condition.
• This highlights the need for continued research into the biological and psychological markers of schizophrenia. Nevertheless, the findings suggest that the application of standardized tools like the DSM-5 play a critical role in improving diagnostic consistency in clinical practice.

Question 2

❌ Diagnosis of schizophrenia has low validity:

Answer 2

• Cheniaux et al. (2009) had two psychiatrists independently diagnosed 100 patients using both the ICD and DSM criteria. The first psychiatrist diagnosed 26 patients with schizophrenia using DSM and 44 using ICD, while the second psychiatrist diagnosed only 13 with DSM and 24 with ICD.
• This demonstrates that there is inconsistency between psychiatrists and diagnostic systems, meaning the diagnosis of schizophrenia is not reliable. As a result, the diagnosis and treatment of schizophrenia may depend more on the psychiatrist consulted rather than the actual symptoms presented.
• This limits the validity and reliability of the diagnostic process, leading to potential misdiagnosis, incorrect prognosis, and inappropriate treatment plans.

Question 3

❌ Situational factors can effect the validity of a schizophrenia diagnosis:

Answer 3

• Rosenhan (1973) conducted a study in which 8 confederates (pseudopatients) visited 12 hospitals, claiming to hear voices before admission but behaving normally once admitted. Despite their normal behaviour, staff diagnosed 11 with schizophrenia and one with manic depression, and the average hospital stay was 19 days. 35 genuine patients identified the pseudopatients as sane, but staff misinterpreted normal behaviour as evidence of mental illness.
• This demonstrates that psychiatric staff may struggle to distinguish between sanity and insanity, highlighting the potential for diagnostic methods like the DSM to lack validity.
• However, it could be argued that overdiagnosis is a protective measure, ensuring genuine cases are not overlooked. Additionally, Rosenhan’s study is over 40 years old, and advancements in diagnostic tools, such as revisions to the DSM, may reduce its relevance today.
• Despite these arguments, Rosenhan’s findings suggest that situational factors, like the clinical environment, continue to influence diagnosis, thereby challenging the validity and reliability of psychiatric diagnostic practices.

Question 4

❌ High co-morbidity limits the validity of the diagnosis:

Answer 4

• Buckley et al. (2009) found that around 50% of patients with schizophrenia also experience depression, 47% have substance abuse issues, 29% suffer from PTSD, and 23% present with OCD.
• This demonstrates that schizophrenia frequently occurs alongside other mental illnesses, creating challenges in distinguishing between disorders. If two conditions consistently co-occur, it raises the question of whether they are distinct disorders or part of a single condition. The high rates of co-morbidity result in a confusing clinical picture, reducing confidence in the validity of schizophrenia as a standalone diagnosis.
• Consequently, this lack of clarity can have implications for the application of the diagnosis, and it may hinder appropriate treatment and prognosis, as clinicians may struggle to identify which disorder to prioritize. Therefore, the overlap between schizophrenia and other mental illnesses undermines the accuracy and usefulness of current diagnostic systems.