Psychosis prediction: 12-month follow up of a high-risk ("prodromal") group

Intervention in the prodromal phase of schizophrenia and related psychoses may result in attenuation, delay or even prevention of the onset of psychosis in some individuals. However, a "prodrome" is difficult to recognise prospectively because of its nonspecific symptoms.This study set out to recruit and follow up subjects at high risk of transition to psychosis with the aim of examining the predictive power for psychosis onset of certain mental state and illness variables.Symptomatic individuals with either a family history of psychotic disorder, schizotypal personality disorder, subthreshold psychotic symptoms or brief transient psychotic symptoms were assessed and followed up monthly for 12 months or until psychosis onset.Twenty of 49 subjects (40.8%) developed a psychotic disorder within 12 months. Some highly significant predictors of psychosis were found: long duration of prodromal symptoms, poor functioning at intake, low-grade psychotic symptoms, depression and disorganization. Combining some predictive variables yielded a strategy for psychosis prediction with good sensitivity (86%), specificity (91%) positive predictive value (80%) and negative predictive value (94%) within 6 months.This study illustrates that it is possible to recruit and follow up individuals at ultra high risk of developing psychosis within a relatively brief follow-up period. Despite low numbers some highly significant predictors of psychosis were found. The findings support the development of more specific preventive strategies targeting the prodromal phase for some individuals at ultra high risk of schizophrenia.     

Transition to psychosis: 6-month follow-up of a Chinese high-risk group in Hong Kong

OBJECTIVES: The identification of individuals at high risk of becoming psychotic within the near future creates opportunities for early intervention before the onset of psychosis. This study sets out to identify a group of symptomatic young people in a Chinese population with the high likelihood of transition to psychosis within a follow-up period of 6 months, and to determine the rate of transition to psychosis in this group. METHOD: Symptomatic individuals with a family history of psychotic disorder, sub-threshold psychotic symptoms or brief transient psychotic symptoms were identified using the operationalized criteria of an 'At Risk Mental State'. The individuals were prospectively assessed monthly on a measure of psychopathology for 6 months. RESULTS: Eighteen out of 62 individuals (29%) made the transition to frank psychosis within a 6 month follow-up period, with the majority occurring within 3 months. In addition, significant differences were found in the intake Positive and Negative Syndrome Scale, Comprehensive Assessment of 'At Risk Mental State' and Global Assessment of Functioning scores between the group that ultimately became psychotic and the group that did not. CONCLUSION: The period of the highest risk of transition to psychosis was within the 3 months after the study began. Thus, distressed youths in our outpatient clinic, who meet the high-risk criteria should be monitored most closely in the initial 3 months, particularly those individuals with high levels of psychopathology and functional decline.     

Obstetric complications and transition to psychosis in an "ultra" high risk sample

OBJECTIVE: An association between birth and pregnancy complications and the later development of schizophrenia has been described for decades and obstetric complications (OCs) have been proposed as a vulnerability marker for psychosis in line with the neurodevelopmental hypothesis of psychotic disorders. Previous studies of OCs have focused on established schizophrenia. In this study, the association between OCs and the development of psychotic disorder was studied in a group of 74 young people identified as being at very high risk for the first onset of psychosis. METHOD: The "ultra" high risk (UHR) cohort was identified by the presence of subthreshold psychotic symptoms, or a combination of first-degree relative with a psychotic disorder and recent functional decline. Thirty-eight per cent of the cohort developed an acute psychotic episode over the 12-month period after recruitment. As a component of a larger research study, the level of OCs experienced by the UHR cohort was assessed at intake. RESULTS: Obstetric complications were not associated with the later development of psychosis in the UHR group included in this study. CONCLUSIONS: This study does not support a role for OCs as a risk factor for the later development of psychosis; however, we cannot conclude that they should be completely ignored as a candidate risk factor for onset of psychosis. A number of weaknesses of the study suggest that it may be premature to dismiss OCs as a risk factor for the development of psychosis and further research is urged in this area.     

Cannabis use is not associated with the development of psychosis in an 'ultra' high-risk group

BACKGROUND: The association between cannabis use and the development of a first psychotic episode was studied in a group of 100 young people identified as being at very high risk for the onset of psychosis. METHOD: The 'ultra' high risk cohort was identified by the presence of subthreshold psychotic symptoms, or a combination of first-degree relative with a psychotic disorder and recent functional decline. Thirty-two per cent of the cohort developed an acute psychotic episode over the 12-month period after recruitment. As a component of a larger research study, the level of cannabis use by participants in the year prior to enrollment in the study was assessed at intake. RESULTS: Cannabis use or dependence in the year prior to recruitment to this study was not associated with a heightened risk of developing psychosis over the following 12-month period and therefore did not appear to contribute to the onset of a psychotic disorder. CONCLUSION: The results of this study suggest that cannabis use may not play an integral role in the development of psychosis in a high-risk group. While this study does not support a role for cannabis in the development of first-episode psychosis, we cannot conclude that cannabis use should be completely ignored as a candidate risk factor for onset of psychosis. A number of weaknesses of the study (the low level of cannabis use in the current sample, the lack of monitoring of cannabis use after intake) suggest that it may be premature to dismiss cannabis use as a risk factor for the development of psychosis and further research is urged in this area.     

Testing the Ultra High Risk (prodromal) criteria for the prediction of psychosis in a clinical sample of young people

Criteria for identifying individuals at imminent risk for onset of a psychotic disorder, that is "prodromal" for psychosis, have recently been described. The current study set out to test the predictive validity of these criteria in a sample of help-seeking young people aged 15-24 years who were referred to, but not necessarily treated at, a psychiatric service. Ultra High Risk (UHR) status was determined at baseline and psychosis status was assessed at 6 month follow up. Baseline psychosocial functioning was also assessed as a possible predictor of psychosis. In the sample of 292 individuals, 119 (40.7%) met UHR criteria. Of these UHR+ people, 12 became psychotic within 6 months and 107 did not. Only one person not meeting UHR criteria developed psychosis in the follow up period. Sensitivity, specificity, positive predictive value and negative predictive value of UHR+ status for prediction of psychosis were, respectively, 0.923 (95% CI 0.621, 1), 0.616 (95% CI 0.556, 0.673), 0.101 (95% CI 0.056, 0.173) and 0.994 (95% CI 0.963, 1). UHR+ individuals were significantly more likely to become psychotic than UHR- individuals (Odds Ratio 19.3, 95% CI 2.5, 150.5). Low functioning at baseline was associated with psychosis onset in the whole sample and in the UHR group. The transition to psychosis rate was much lower than in previous samples. This may be a due to the sample being a more general one, not identified as possibly "prodromal". Other potential causes of this reduction in transition are also explored.     

Generalized and specific neurocognitive deficits in prodromal schizophrenia.

BACKGROUND: Neurocognitive deficits are considered to be central to the pathophysiology of schizophrenia, and the neurodevelopmental model suggests that such deficits precede full-blown psychosis. The present study examined performance on a broad neuropsychological battery of young subjects considered to be at clinical high risk for schizophrenia, who were subsequently followed to determine clinical outcome. METHODS: Subjects were 38 clinical high-risk patients (58% male patients; mean age = 16.5) and 39 sex- and age-matched healthy control subjects. At baseline, all high-risk patients had attenuated (subpsychotic) schizophrenialike positive symptoms. Clinical follow-up data of at least 6 months duration was available on 33 patients, of whom 12 developed nonaffective psychotic disorders. RESULTS: At baseline, clinical high-risk patients had significantly impaired global cognitive performance relative to control subjects and to estimates of their own prior intellectual functioning. Measures of verbal memory and executive functioning/working memory showed significantly greater impairments; visuospatial functioning was relatively spared. Prodromal patients who later developed psychosis had significantly lower verbal memory scores at baseline compared with patients who remained nonpsychotic. CONCLUSIONS: Verbal memory deficits may be an important risk marker for the development of schizophrenia-spectrum psychotic disorders, possibly indicating the presence of a prefrontal-hippocampal neurodevelopmental abnormality. Generalized neurocognitive impairment may be a nonspecific vulnerability marker.     

Obsessive-compulsive and panic symptoms in patients with first-admission psychosis

OBJECTIVE: The occurrence, persistence and specificity of the association between comorbid obsessive-compulsive and panic symptoms and three psychotic disorders--schizophrenia/schizoaffective disorder, bipolar disorder with psychosis, and major depression with psychosis--were examined in a first-admission, epidemiologically defined group of patients with psychotic symptoms. METHOD: The Structured Clinical Interview for DSM-III-R obsessive-compulsive and panic modules were administered at baseline and 24-month follow-up to patients with schizophrenia/schizoaffective disorder (N=225), bipolar disorder with psychosis (N=138), and major depression with psychosis (N=87) participating in the Suffolk County (N.Y.) Mental Health Project. The rates of subsyndromal symptoms and disorder criteria met were compared across the three psychosis groups. Recognition and treatment of anxiety symptoms at initial discharge and impact of the baseline presence of anxiety symptoms on 24-month clinical status were also examined. RESULTS: Obsessive-compulsive and panic symptoms were present at baseline in 10%-20% of all three groups. There was no specific association between obsessive-compulsive symptoms and any specific psychosis diagnosis; however, women with major depression with psychosis had a significantly higher rate of panic symptoms than the other two groups, and schizophrenia/schizoaffective disorder patients with baseline panic symptoms were significantly more likely to exhibit positive symptoms of psychosis after 24 months. CONCLUSIONS: The authors found no specific association between obsessive-compulsive symptoms and diagnosis early in the illness course, but the finding of an association between panic symptoms and psychotic depression among female patients and between baseline panic and positive psychotic symptoms in schizophrenia/schizoaffective disorder patients at 24 months suggests the need for further study.     

What factors are related to delayed treatment in individuals at high risk for psychosis?

Background: Previous studies have shown that the individuals at high risk for psychosis suffer from depression, anxiety, and deficits in social functioning. The present report describes help-seeking behaviours, baseline psychopathology, and duration of attenuated psychotic symptoms (DUAPS) and their associations with other variables. Methods: Using the Comprehensive Assessment of At-Risk Mental States (CAARMS), we conducted systematic evaluations of individuals at high risk for psychosis. Help-seeking behaviours, current Axis I diagnoses, DUAPS, and baseline psychopathology were investigated. Demographic and clinical characteristics of short and long DUAPS groups were compared. Results: Thirty-eight subjects were recruited from nine centres. Participants seldom sought psychiatric services at their first help-seeking contact, and the mean DUAPS was 22.00 ± 28.59 months. Most participants had current Axis I diagnoses, and depressive disorder NOS was the most common of these. Higher levels of depression, anxiety, obsessive-compulsive symptoms, and functional impairment were also identified. We found no significant differences between short and long DUAPS groups in baseline psychopathology. However, we observed significantly lesser distressing intensity of thought contents and significantly greater social impairment in the long-DUAPS group. Conclusion: These findings suggest that high-risk subjects frequently received delayed treatment despite symptomatic distress and functional impairment. No direct evidence supporting the delayed effect of the DUAPS on baseline psychopathology was found.     

Gender differences in symptoms, functioning and social support in patients at ultra-high risk for developing a psychotic disorder

Gender differences have been widely observed in the clinical presentation, psychosocial functioning and course of illness in first-episode and chronic patients suffering from schizophrenia. However, little is known about gender differences in the psychosis prodrome. This study investigated gender differences in symptoms, functioning and social support in individuals at ultra-high-risk for developing a psychotic disorder. Sixty-eight ultra-high-risk patients were assessed at baseline, and twenty-seven returned for follow-up assessments approximately 6 and 12 months later. Clinical symptoms and functioning were assessed by clinical interview; social support was measured using a self-report questionnaire. There were no gender differences in demographic variables, symptoms or functioning at baseline. Males were found to have significantly higher levels of negative symptoms and marginally lower levels of functioning when baseline and follow-up time points were considered collectively. Additionally, females reported higher levels of social support at baseline. Differences in negative symptoms were found to mediate differences in functioning between male and female patients. This study suggests that gender based differences in symptom presentation and functional outcome may predate conversion to psychosis. Follow-up studies should examine the relationship between symptoms, functioning and social support in this population.     

Prediction of conversion to psychosis: review and future directions

This article reviews recent findings on predictors of conversion to psychosis among youth deemed at ultra high risk (UHR) based on the presence of subpsychotic-intensity symptoms or genetic risk for psychosis and a recent decline in functioning. Although transition rates differ between studies, the most well powered studies have observed rates of conversion to full psychosis in the 30-40% range over 2-3 years of follow-up. Across studies, severity of subthreshold positive symptoms, poorer social functioning, and genetic risk for schizophrenia appear to be consistent predictors of conversion to psychosis, with algorithms combining these indicators achieving positive predictive power > 80%. Nevertheless, a substantial fraction of UHR cases do not convert to psychosis. Recent work indicates that UHR cases who present with lower levels of negative symptoms and higher levels of social functioning are more likely to recover symptomatically and no longer meet criteria for an at-risk mental state. In general, it appears that about 1/3 of UHR cases convert to psychosis, about 1/3 do not convert but remain symptomatic and functionally impaired, and about 1/3 recover symptomatically and functionally. Continued efforts to detect early risk for psychosis are critical for informing early intervention and provide increasing promise of delaying or even preventing the onset of psychosis.     

Non-reduction in hippocampal volume is associated with higher risk of psychosis

Previous research using MRI scans has shown reduced hippocampal volumes in chronic schizophrenia and first-episode psychosis compared to well subjects. There are few MRI volumetric studies of high-risk cohorts and no studies that have compared structural measures between high-risk subjects who later developed a psychotic illness and those who did not. Therefore, the question of whether structural changes to the hippocampi precede the onset of an acute psychotic episode has not been answered.Hippocampal and whole brain volumes of 60 people at ultra high-risk (UHR) of developing a psychotic episode (identified through state and trait criteria) were obtained through MRI scan and compared with subjects with first episode psychosis (FEP: n=32), and no mental illness (n=139). Thirty-three percent (n=20) of the UHR cohort developed a psychotic disorder during the 12-month period following the MRI scan.The UHR group as a whole, like the FEP group, had significantly smaller left and right hippocampal volumes than the normal comparison group. Contrary to our initial hypothesis, the left hippocampal volume of the UHR subjects who developed a psychotic disorder was larger than the UHR-non-psychotic subgroup and the FEP group, but no differences were found between the UHR-psychotic and normal groups. The right hippocampus of the UHR-non-psychotic group was significantly smaller than the Normal group but not different to the FEP group. Furthermore, a larger left hippocampal volume of the UHR cohort at intake was associated with the subsequent development of acute psychosis rather than smaller volumes.These results contradicted the expected outcomes, which had been influenced by the neurodevelopmental model of the development of psychosis and an earlier study comparing hippocampal volumes of first episode, chronic schizophrenia and normal populations. One implication of these results is that a process of dynamic central nervous system change may occur during the onset phase of schizophrenia and related disorders, rather than earlier in life as suggested by the neurodevelopmental model. Alternatively, selection factors associated with the UHR cohort may have created a bias in the results. Replication of these results is required in other high-risk cohorts.     

Early-onset psychotic disorders: course and outcome over a 2-year period

OBJECTIVE: To examine the course and outcome of early-onset psychotic disorders. METHOD: These are data from a longitudinal, prospective study of youths with psychotic disorders. Standardized diagnostic and symptom rating measures were used. RESULTS: Fifty-five subjects with the following disorders have been recruited: schizophrenia (n = 18), bipolar disorder (n = 15), psychosis not otherwise specified (n = 15), schizoaffective disorder (n = 6), and organic psychosis (n = 1). Follow-up assessments were obtained on 42 subjects at year 1 and 31 subjects at year 2. Youths with schizophrenia had more chronic global dysfunction, whereas subjects with bipolar disorder overall had better functioning, with a cyclical course of illness. However, according to results of a regression model, premorbid functioning and ratings of negative symptoms, but not diagnosis, significantly predicted the highest level of functioning over years 1 and 2. CONCLUSIONS: Course and level of functioning differentiated bipolar disorder from schizophrenia. However, premorbid functioning and ratings of negative symptoms were the best predictors of functioning over the follow-up period. These findings are consistent with the adult literature, and they further support that psychotic illnesses in young people are continuous with the adult-onset forms.     

Diagnostic stability 2 years after treatment initiation in the early psychosis intervention programme in Singapore

OBJECTIVE: To evaluate the diagnostic stability of psychotic disorders over a 2 year period in patients presenting with first-episode psychosis. METHODS: One hundred and fifty-four patients were recruited from an early psychosis intervention programme (EPIP). They were diagnosed by the attending psychiatrist using the Structured Clinical Interview for DSM-IV Axis I at first contact (baseline) and after 24 months. The diagnoses were classified into the following categories: schizophrenia spectrum disorders (schizophrenia, schizophreniform disorder and schizoaffective disorder), affective psychosis (bipolar and major depressive disorders with psychotic symptoms), and other non-affective psychosis (delusional disorder, psychosis not otherwise specified and brief psychotic disorder). Two measures of stability, the prospective and the retrospective consistency were determined for each diagnosis. RESULTS: The diagnoses with the best prospective consistency were schizophrenia (87.0%) and affective psychosis (54.5%). The shift into schizophrenia spectrum disorder was the most frequent diagnostic change. Duration of untreated psychosis was found to be the only significant predictor of shift. CONCLUSION: It is difficult to make a definitive diagnosis at first contact. The clinical need to review the diagnosis throughout the period of follow up is emphasized.     

Impairment of olfactory identification ability in individuals at ultra-high risk for psychosis who later develop schizophrenia

OBJECTIVE: Previous investigation has revealed stable olfactory identification deficits in neuroleptic-naive patients experiencing a first episode of psychosis, but it is unknown if these deficits predate illness onset. METHOD: The olfactory identification ability of 81 patients at ultra-high risk for psychosis was examined in relation to that of 31 healthy comparison subjects. Twenty-two of the ultra-high-risk patients (27.2%) later became psychotic, and 12 of these were diagnosed with a schizophrenia spectrum disorder. RESULTS: There was a significant impairment in olfactory identification ability in the ultra-high-risk group that later developed a schizophrenia spectrum disorder but not in any other group. CONCLUSIONS: These findings suggest that impairment of olfactory identification is a premorbid marker of transition to schizophrenia, but it is not predictive of psychotic illness more generally.     

Psychosis in a pediatric mood and anxiety disorders clinic: phenomenology and correlates

OBJECTIVES: To examine the demographics and phenomenology of psychosis in a sample of children and adolescents referred to a mood and anxiety disorders clinic. METHOD: Patients (N = 2,031) were assessed with the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present Episode version and classified as definite, probable, or nonpsychotic. Clinical and demographic characteristics of the groups were compared,and symptoms of psychosis were analyzed using factor analysis. RESULTS: Definite psychotic symptoms were seen in approximately 90 (4.5%) patients: 80% of these reported hallucinations (mainly auditory), 22% delusions, and 3.3% thought disorder. Of the patients with definite psychotic symptoms, 24% had bipolar disorder, 41% had major depression, 21% had subsyndromal depression, and 14% had schizophrenia spectrum disorders (schizophrenia and schizoaffective disorders). Factor analysis of the definite psychotic symptoms yielded 4 factors: hallucinations, thought disorder, delusions, and manic thought disorder. Psychotic patients had a higher frequency of comorbid disorders and suicidal ideation than nonpsychotic patients. CONCLUSIONS: Outpatient youngsters with mood disorders frequently present with psychotic symptoms, in particular auditory hallucinations. These patients commonly have comorbid psychiatric disorders and suicidal ideation.     

Risk factors for transition to first episode psychosis among individuals with 'at-risk mental states'

Recently developed criteria have been successful at identifying individuals at imminent risk of developing a psychotic disorder, but these criteria lead to 50-60% false positives. This study investigated whether measures of family history, peri-natal complications, premorbid social functioning, premorbid personality, recent life events and current symptoms would be able to improve predictions of psychosis in a group of young, help-seeking individuals who had been identified as being at risk. Individuals (N=74) were followed up at least 1 year after initial assessment. Half the sample went on to develop a psychotic disorder. The most reliable scale-based predictor was the degree of presence of schizotypal personality characteristics. However, individual items assessing odd beliefs/magical thinking, marked impairment in role functioning, blunted or inappropriate affect, anhedonia/asociality and auditory hallucinations were also highly predictive of transition, yielding good sensitivity (84%) and specificity (86%). These predictors are consistent with a picture of poor premorbid functioning that further declines in the period up to transition.     

Premorbid functioning in early-onset psychotic disorders

OBJECTIVE: To examine the premorbid characteristics of youths with early-onset psychotic disorders. METHOD: Subjects with early-onset psychotic disorders received an extensive diagnostic evaluation upon entry into the study, including a historic review of premorbid functioning using the Premorbid Adjustment Scale. RESULTS: Youths with schizophrenia (n = 27), bipolar disorder (n = 22), and psychosis not otherwise specified (NOS) (n = 20) were included. High rates of premorbid behavioral problems and academic difficulties were noted across all subjects. Youths with schizophrenia had higher rates of premorbid social withdrawal and global impairment. They also tended to have fewer friends. The psychosis NOS group had significantly higher rates of abuse histories and posttraumatic stress disorder. CONCLUSIONS: Premorbid abnormalities are common features of early-onset psychotic disorders. The social withdrawal and peer problems specific to youths with schizophrenia likely represent early manifestations of negative symptoms. The abuse histories in the psychosis NOS group may explain the atypical nature of their reported psychotic symptoms, which in many cases are likely posttraumatic phenomena.     

Investigating the association between neurocognition and psychosis in bipolar disorder: further evidence for the overlap with schizophrenia

Objectives: In schizophrenia, a distinction is made between psychosis with developmental and cognitive impairment on the one hand and psychosis without developmental impairment and positive symptoms on the other. In this study, we investigated whether this model can be extended to bipolar disorder by testing the hypothesis that neurocognitive functioning is inversely related to positive psychotic symptoms in bipolar disorder. Methods: Neurocognitive functioning and psychopathology were assessed in (i) 76 patients with bipolar disorder, (ii) 39 of their healthy first‐degree relatives, and (iii) 61 healthy controls. Cognitive performance of bipolar patients and their first‐degree relatives was investigated, taking into account the possible moderating effect of the level of expression of psychosis in patients and relatives. Results: Bipolar patients showed impaired cognitive performance on multiple cognitive domains, whereas performance of their relatives was comparable to that of controls. A history of psychotic symptoms in patients was suggestive of less likelihood of cognitive alterations in relatives, and the presence of subclinical psychotic symptoms within the group of relatives predicted better cognitive performance. Conclusions: The finding of similar psychosis‐cognition associations in bipolar disorder as implied by the two pathways leading to nonaffective psychotic disorders suggests that this model might be extended to the continuum spanning affective and nonaffective psychosis. This is in line with the idea of a partially overlapping vulnerability to bipolar disorder and schizophrenia and provides an explanation for the apparent differences in cognitive alterations in those at risk for the two disorders.     

Emotion recognition in individuals at clinical high-risk for schizophrenia

Problems in the perception of emotional material, in particular deficits in the recognition of negative stimuli, have been demonstrated in schizophrenia including in first-episode samples. However, it is largely unknown if emotion recognition impairment is present in people with subthreshold psychotic symptoms. Here, we examined the capacity to recognize facially expressed emotion and affective prosody in 79 individuals at ultra high-risk for psychosis, 30 clinically stable individuals with first-episode schizophrenia assessed as outpatients during the early recovery phase of illness, and 30 unaffected healthy control subjects. We compared (1) scores for a combined fear-sadness aggregate index across face and voice modalities, (2) summary scores of specific emotions across modalities, and (3) scores for specific emotions for each sensory modality. Findings supported deficits in recognition of fear and sadness across both modalities for the clinical groups (the ultra high-risk and first-episode group) as compared with the healthy controls. Furthermore, planned contrasts indicated that compared with the healthy control subjects, both clinical groups had a significant deficit for fear and sadness recognition in faces and for anger recognition in voices. Specific impairments in emotion recognition may be apparent in people at clinical high-risk for schizophrenia before the full expression of psychotic illness. The results suggest a trait deficit and an involvement of the amygdala in the pathology of ultra high-risk states.     

Psychotic symptoms and paranoid ideation in a population-based sample of 95-year-olds.

OBJECTIVE: To examine the 1-year prevalence of psychotic symptoms and schizophrenia in nondemented 95-year-olds, and to examine the relation between psychotic symptoms and other psychiatric symptoms, sensory impairments, and cognitive functioning. PARTICIPANTS: The representative sample was 95-year-olds living in G?teborg, Sweden (N = 338). Individuals with dementia were excluded (N = 175), leaving 163 subjects for this study. DESIGN: This was a cross-sectional population study, including psychiatric and physical examinations, cognitive tests, and interviews with close informants. MEASUREMENTS: Diagnosis of schizophrenia, psychotic symptoms, paranoid ideation and dementia according to Diagnostic and Statistical Manual of Mental Disorders, Third Revision (DSM-III) were measured. Cognitive function was tested with the Mini-Mental State Exam. Other psychiatric symptoms were measured by the Comprehensive Psychopathological Rating Scale. RESULTS: The one-year prevalence of any psychotic symptom was 7.4% (95% confidence interval [CI] 3.8-12.5); including hallucinations 6.7% (95% CI 3.4-11.8) and delusions 0.6% (95% CI 0.0-3.4). Four (2.4%) individuals fulfilled DSM-III-R criteria for schizophrenia. Individuals with psychotic symptoms or paranoid ideation did not differ regarding cognitive functioning compared with individuals without these symptoms. Individuals with hallucinations and paranoid ideation had an increased frequency of previous paranoid personality traits compared with individuals without psychotic symptoms and paranoid ideation. No individuals with psychotic symptoms had a formal thought disorder, incoherence of speech, or flat affect. CONCLUSION: The authors found a high prevalence of psychotic symptoms, paranoid ideation, and schizophrenia in the very old. Most of the symptoms were elucidated by information from key informants, illustrating the importance of including relatives in the evaluation of elderly persons.