Psychiatric diagnoses are not mental processes: Wittgenstein on conceptual confusion

Empirical explanation and treatment repeatedly fail for psychiatric diagnoses. Diagnosis is mired in conceptual confusion that is illuminated by Ludwig Wittgenstein's later critique of philosophy (Philosophical Investigations). This paper examines conceptual confusions in the foundation of psychiatric diagnosis from some of Wittgenstein's important critical viewpoints.

Diagnostic terms are words whose meanings are given by usages not definitions. Diagnoses, by Wittgenstein's analogy with 'games', have various and evolving usages that are connected by family relationships, and no essence or core phenomenon connects them. Their usages will change according to the demands and contexts in which they are employed. Diagnoses, like many psychological terms, such as 'reading' or 'understanding', are concepts that refer not to fixed behavioural or mental states but to complex apprehensions of the relationship of a variety of behavioural phenomena with the world. A diagnosis is a sort of concept that cannot be located in or explained by a mental process.

A diagnosis is an exercise in language and its usage changes according to the context and the needs it addresses. Diagnoses have important uses but they are irreducibly heterogeneous and cannot be identified with or connected to particular mental processes or even with a unity of phenomena that can be addressed empirically. This makes understandable not only the repeated failure of empirical science to replicate or illuminate genetic, neurophysiologic, psychic or social processes underlying diagnoses but also the emptiness of a succession of explanatory theories and treatment effects that cannot be repeated or stubbornly regress to the mean. Attempts to fix the meanings of diagnoses to allow empirical explanation will and should fail as there is no foundation on which a fixed meaning can be built and it can only be done at the cost of the relevance and usefulness of diagnosis.