Table II. Classification of chronic delusional psychoses in the French school of psychiatry in the first half of the 20th century. Adapted from ref 5: Ey H, Bernard P, Brisset C. Manuel de psychiatrie. Paris, France: Masson; 1978:506-533. Copyright © Masson 1978.

Diagnostic categories	Subtypes	Authors	Key features
	Delusional claimants (litigators; discoverers; passionate idealists) Délires de revendication (quérulents processifs; inventeurs; idéalistes passionnés)	G. G. de Clérambault	A delusional state develops, as a delusional “sector” wedged into reality, on the basis of a paranoid predisposi-tion. The delusional system is organized around one initial delusional postulate. Reality testing is intact. Emotional exaltation, hypersthenia
Chronic systematized delusional disorders (paranoia) Délires chroniques systématisés (paranoïa)	Passionate delusions (erotomania; delusional jealousy) Délires passionnels (érotomanie, jalousie)
	Delusional sensitivity in inter-personal relationships Délire sensitif de relation	Related to Kretschmer's Beziehungswahn	Hyposthenia
	Delusional thinking Délire d'interprétation	Sérieux & Capgras. Concept related to Wahnwahrnehmung, and to Esquirol's intellectual monomany	Delusional reasoning, deductions or inductions. The patients interpret normal perceptions, according to a systematic delusional system that may develop as a “network.” No hallucinations, no querulancy; no evolution toward dementia
Chronic hallucinatory psychosis Psychose hallucinatoire chronique		G. Ballet. G. G. de Clérambault (automatisme mental)	Hallucinations (auditory, sensory, somatic)
Fantastic psychoses Psychoses fantastiques		Dupré. Concept related to Kraepelin's paraphrenias	“Imagination” is the main delusional mechanism