Delusional disorders: boundaries of a concept

Area of Science:

• Psychiatry
• Clinical Psychology
• History of Medicine

Background:

• The term "delusional disorder" was formally introduced in the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III) in 1987.
• This concept has historical roots, with significant early delineation by Kraepelin and further development in France during the early 20th century.

Purpose of the Study:

• To examine the historical evolution of thinking regarding delusional syndromes, particularly in France.
• To critically assess the current diagnostic distinctions between delusional disorder and schizophrenia.
• To evaluate whether current classifications adequately support research into the underlying mechanisms of delusional disorders.

Main Methods:

• Historical analysis of psychiatric literature and diagnostic criteria evolution.
• Comparative review of French and contemporary conceptualizations of delusional syndromes.
• Conceptual critique of diagnostic distinctions based on descriptive convenience versus etiological understanding.

Main Results:

• The modern concept of delusional disorder builds upon historical frameworks but its current definition primarily relies on descriptive features.
• Historical French contributions highlight a nuanced understanding of delusional syndromes that may be obscured in current classifications.
• Current distinctions between delusional disorder and schizophrenia appear based on convenience rather than a deep understanding of potential underlying mechanisms.

Conclusions:

• The current diagnostic approach to delusional disorder may not be sufficiently grounded in mechanistic understanding.
• Relying on descriptive convenience for diagnostic distinctions could be a barrier to advancing research on the etiology and phenomenology of delusional disorders.
• A re-evaluation of diagnostic frameworks is needed to better facilitate research into the phenotypic variations observed in delusional syndromes.