Vanheule, Stijn. The Subject of Psychosis: A Lacanian Perspective. Palgrave Macmillan, 2011.
A delusion is primarily a speech event which is why he studies delusions in terms of ruptures in the conventinal use of speech. 98
… at the basis of psychotic outbreak a dramatic mental decomposition can be found and a delusion is an adaptive reaction to this problem of disintegration. … Delusions defend the subject against radical breakdown. … [but] delusions do not inherently provide stability. Only to the extent that a delusion creates an anchor, based on which the process of signification is stablized, can it be thought to be a stabilizing factor in mental life. 99-100