background Little is known about non-affective non-organic psychoses of higher ages. Few prospective studies have been carried out during the last 10 years to fill in existing gaps of knowledge.
aim The psite study is an ongoing crosssectional and longitudinal study that aims at a better understanding of the aetiology, phenomenology and prognosis of the psychoses of higher ages.
methods Forty patients with onset after age 45 years (late onset psychosis, lop, n=18) or age 65 years (very late onset psychosis, vlop, n=22) underwent extensive clinical and neuropsychological testing. Demographics and symptomatology for lifetime and present state symptoms were assessed and comparisons were made between lop and vlop. 
results Thirteen patients (34%) had a first episode. Of the remainder, 9 (36%) patients had a single episode with partial or full remission, 6 (24%) patients had multiple episodes and in 10 (40%) patients the course was chronic. Paranoid delusions dominated the clinical picture and were seen in 39 (98%) of patients. Auditory hallucinations were present in 27 patients (65%), with 9 (23%) patients reporting visual hallucinations and 10 (25%) reporting olfactory hallucinations. lop more often displayed delusions of grandiosity (33% versus 0%, p = .003), delusions of passivity (27% versus 5%, p = .041), religious delusions (33% versus 5%, p = .017) and tactile hallucinations (27% versus 5%, p = .041) than patients with vlop. In addition, delusions of the former more often were of a bizarre content (50% versus 9%, p = .004). No differences were seen regarding negative symptoms (50% versus 43%, p = .666) or global functioning (GAF-score 54 versus 57, p = .500).
conclusion Both lop and vlop are dominated by paranoid delusions and auditory hallucinations. The delusions of the old are however more intelligible and non-bizarre. In contrast to previous reports, negative symptoms were found to be quite common.