A recent study has raised significant questions regarding the reliability of diagnostic interviews used in the assessment of mental health conditions. These interviews, often regarded as the ‘gold standard’ for diagnosing disorders such as anxiety, depression, and substance use issues, vary considerably in their effectiveness across different conditions, according to research published in Jama Network Open.
Variability in Diagnostic Reliability
Laura Duncan, a psychiatry professor at McMaster University in Ontario, Canada, who co-authored the study, observed that while diagnostic interviews are widely trusted in both clinical practice and research, they frequently do not provide a robust benchmark for validity and consistency. Despite the longstanding mixed evidence surrounding their reliability, these interviews remain the preferred method, likely due to the absence of superior alternatives.
The study synthesised findings from various research papers focusing on the “test-retest reliability” of diagnostic interviews conducted between February 2024 and September 2025. By employing Cohen’s kappa coefficient, the researchers aimed to quantify the reliability of these interviews across different mental health disorders. The results indicated that the average reliability was generally higher for substance use disorders, with opioid use disorder achieving the highest reliability overall. Duncan attributed this trend to the behavioural criteria used to diagnose substance-related issues, which are often more straightforward to quantify than emotional or psychological symptoms.
Call for Specificity in Diagnostic Tools
Dr Michael First, a psychiatrist at Columbia University and author of the Structured Clinical Interview for DSM-5 (SCID), expressed frustration with the study’s limited scope. While he acknowledged that diagnostic interviews can indeed vary in reliability and frequently misdiagnose patients, he emphasised the need for more detailed information on which specific instruments perform best. “It would be beneficial to identify which tools are most reliable based on this research,” he said. “However, there’s simply not enough detailed information here.”
Duncan noted that the constraints of available literature during the study period limited their ability to provide a more comprehensive analysis. The review encompassed various diagnostic tools, including the SCID and the Mini International Neuropsychiatric Interview (Mini), which assess multiple mental health conditions, as well as more focused instruments like the Clinically Administered PTSD Scale (CAPS).
Distinguishing Interview Types
One of First’s key criticisms concerned the study’s approach to categorising interviews. He pointed out that fully structured interviews, which adhere strictly to a pre-determined script, tend to yield more consistent diagnoses than semi-structured interviews, where clinicians can adapt their questioning based on patient responses. “If a patient provides contradictory information, the interviewer is not permitted to highlight that,” First explained. “This rigidity makes structured interviews more suitable for large-scale epidemiological studies.”
In contrast, semi-structured interviews allow trained clinicians the flexibility to probe deeper into vague or contradictory answers, potentially leading to more accurate diagnoses. However, this adaptability can also result in variability in patient responses across different sessions, complicating the reliability of the diagnosis.
A Need for Enhanced Rigor
Both Duncan and First agree on the necessity for more rigorous methods in psychiatric diagnosis. Duncan acknowledged the limitations in her study regarding the clarity of interview formats, stating that much of the relevant information was either unclear or underreported in the existing literature. This reinforces the argument for greater integrity and precision in the development of diagnostic tools.
Despite his involvement in creating structured interviews, First admitted they are not ideal. “For decades, we’ve been hoping for more objective laboratory tests to emerge for mental health conditions,” he said, reflecting on the ongoing search for improved diagnostic methods.
Duncan suggested a future direction where clinicians might shift away from strictly defined diagnostic categories. Instead, she advocates for understanding mental health symptoms on a continuum, recognising the complexity of human emotions and experiences.
Why it Matters
The implications of this study are profound, highlighting a critical need for reform in mental health diagnostics. As the mental health landscape evolves, ensuring the reliability and validity of diagnostic tools is paramount for accurate treatment and patient care. Moving towards a more nuanced understanding of mental health—one that embraces the spectrum of human experience—could lead to better outcomes for individuals seeking help. This shift is not just necessary; it is essential for the advancement of mental health care in an increasingly complex world.
