In chapter 2 we described and quantified the prevalence and characteristics of RDs, and the co-occurrence of RDs with other delusions, using a semi structured diagnostic interview in older adults diagnosed with either affective or nonaffective psychotic disorders. Results showed that RDs were fairly common in both diagnostic groups, psychotic depression and schizophrenia. RDs were markedly higher among patients with psychotic depression compared to younger samples. RDs with delusions of grandeur, Cotard and Schneider appear to be related to non-affective psychosis (schizophrenia). The delusional characteristic bizarreness and the presence of more psychotic symptoms are significantly more common in this combination of delusions. In psychotic depression, RDs with delusions of guilt occurred predominantly with more symptoms of distress compared to patients without this combination of delusions. In chapter 3 we explored the prevalence and content of religious hallucinations (RHs), how they relate to the diagnosis, and how RDs and RHs related to patients’ denominational background and other aspects of religiousness. Results showed that the prevalence of RHs amounted to 18.7%, no statistically significant difference between the prevalence in schizophrenia (17.5%) and in psychotic depression (9.4%). Moreover, the contents of the RHs about the Devil or Satan were quite common, and more prevalent in patients with psychotic depression. RDs and RHs were significantly more prevalent in psychotic depressed patients who were raised as or were currently affiliated as strict Protestants. Religion is likely to act as a symptom-formation factor for psychotic symptoms in strict Protestant older adults. In chapter 4 we aimed to obtain more insight into the course of RDs over time. Results showed that, although RDs in older adults decline in the clinical course of psychotic depression, the course is unfavorable compared to psychotic depression without RDs with regards to depressive symptom severity. In schizophrenia the most ...