Theories of Delusional Disorders

Abstract

Delusional syndromes can occur in a number of psychiatric, neurological or other disorders. They can also be caused by neurotoxic agents (e.g., heavy metals) as well as substance addiction. There are several hypotheses on the underlying cognitive or emotional processes associated with organic factors of delusional disorders, depending on the patient groups examined and the methods used. The aim of this paper is to provide a comprehensive review and critical assessment of the various, rather heterogeneous theories in this field.

Neuropsychological Research in Delusional Disorder: A Comprehensive Review

“…DD is characterized by false beliefs that are held with firm conviction despite counterevidence and are typically accompanied by strong affect and exaggerated vigilance [14]. These delusional beliefs are usually monothematic and encapsulated and lack the bizarreness of delusions found in schizophrenia [28].…”

“…For instance, lesions in the limbic system and the subcortical structures, predominantly on the left side, have been traditionally associated with delusions [47,48]. However, not all patients with injury in these regions develop delusions, so there must be some further predisposing factors [14]. Alternatively, associations between right-hemisphere impairment and delusional belief have also been frequently discussed [50,51].…”

“…Interestingly, other authors have proposed that intact cognitive functions are necessary for elaborated delusional processing [14]. In other words, it is hypothesized that neuropsychological impairment in DD must be minor, because otherwise complex delusions could not develop.…”

“…They all studied patients diagnosed with schizophrenia. To date, neuropsychological data on delusions in patients without schizophrenia are scarce, and neuropsychological correlates of delusions remain to be identified [14], especially in view of the methodological problems just mentioned.…”

“…Even though a number of reviews focusing on delusions have been published previously [4,11,12,13,14,15], the present review seeks to provide an update and, at the same time, to incorporate a brand new perspective, pointing to the importance of neuropsychological research in understanding delusions. Moreover, we recognize that previous reviews have mainly focused on persecutory delusions, given that this is by far the most prevalent amongst the delusional types.…”