Papers by Peter M. A. J. Dingemans
0051 SCREENING SUBJECTS VULNERABLE TO PSYCHOSIS — RESULTS OF THE EPOS PROJECT IN TURKU CENTRE
Schizophrenia Research, 2006
Attitudes of patients concerning the first psychotic episode and the start of treatment
Schizophrenia Research, 2000
Neuropsychobiology, 2008
other first-episode studies. This discrepancy in findings may be related to differences in subjec... more other first-episode studies. This discrepancy in findings may be related to differences in subject characteristics and DTI methodology. Possible effects of age, gender, level of education and illicit substance use on DTI findings in schizophrenia are discussed.
WC3C PROBABLY PRODROMAL, BUT CERTAINLY ILL: QUALITY OF LIFE AND SOCIAL ADJUSTMENT IN PATIENTS AT RISK OF PSYCHOSIS. RESULTS OF THE EPOS STUDY
Schizophrenia Research, 2006
0180 PATTERNS OF DEPRESSION IN SUBJECTS PUTATIVELY AT RISK FOR PSYCHOSIS
Schizophrenia Research, 2006
0178 QUALITY OF LIFE AND RISK OF PSYCHOSIS. RESULTS OF THE EPOS PROJECT IN TURKU CENTRE
Schizophrenia Research, 2006
0539 DIFFERENTIATION BETWEEN DEPRESSIVE AND NEGATIVE SYMPTOMS IN PATIENTS AT ULTRA HIGH RISK FOR PSYCHOSIS
Schizophrenia Research, 2006
Schizophrenia Research, 2008
Background: The comparison of high-risk populations with different developmental pathways to psyc... more Background: The comparison of high-risk populations with different developmental pathways to psychosis may lend more insight into the heterogeneity of the manifestation of the psychotic syndrome, and possible differing etiological pathways. Aim: To compare high-risk traits and symptoms in two populations at risk for psychosis, i.e. (1) help-seeking adolescents presenting with prodromal symptoms meeting the criteria for At Risk Mental State (ARMS), and (2) adolescents with Multiple Complex Developmental Disorder (MCDD), a PDD-NOS subtype characterized by severe, early childhood-onset deficits in affect regulation, anxieties, disturbed social relationships, and thought disorder. Method: 80 ARMS-and 32 MCDD-adolescents (12-18 years) were compared on prodromal symptoms (Structured Interview of Prodromal Symptoms, and Bonn Scale for the Assessment of Basic Symptoms-Prediction list), and autism traits (Social Communication Questionnaire). In addition, both high-risk groups were compared with 82 healthy controls on schizotypal traits (Schizotypal Personality Questionnaire-Revised). Results: Although the high-risk groups clearly differed in early developmental and treatment histories as well as autism traits, they did not differ with regard to schizotypal traits and basic symptoms, as well as disorganized and general prodromal symptoms. There were, however, group differences in positive and negative prodromal symptoms. Interestingly, 78% of the adolescents with MCDD met criteria for ARMS. Conclusion: These findings suggest that children diagnosed with MCDD are at high risk for developing psychosis later in life, and support the notion that there are different developmental pathways to psychosis. Follow-up research is needed to compare the rates of transition to psychosis in both high-risk groups.
FC10D THE AMSTERDAM CRITICAL PERIOD INTERVENTION IN THE EARLY PHASE OF SCHIZOPHRENIA-LIKE PSYCHOSES
Schizophrenia Research, 2006
0138 NEUROBIOLOGICAL ABNORMALITIES BEFORE AND AFTER THE ONSET OF PSYCHOSIS: A P300 EVENT-RELATED POTENTIAL STUDY
Schizophrenia Research, 2006
FC2F PREMORBID ADJUSTMENT AND SEVERITY OF PSYCHOPATHOLOGY AND FUNCTIONING IN PATIENTS AT RISK OF PSYCHOSIS
Schizophrenia Research, 2006
Schizophrenia Research, 2010
The chance of transition to psychosis in patients at Ultra High Risk for developing psychosis (UH... more The chance of transition to psychosis in patients at Ultra High Risk for developing psychosis (UHR) is 10-15%. The aim of present study was to investigate differences in baseline clinical symptomatology, general level of functioning (GAF-score) and genetic risk between UHR patients who did (UHR+T) or did not (UHR+NT) make a transition to psychosis. Sharpening UHR inclusion criteria may aid in improving prediction of transition to psychosis. The study sample was taken from 285 patients who were examined within the Dutch Prediction of Psychosis Study (DUPS) at the Academic Medical Center of the University of Amsterdam, the Netherlands. Out of 73 included UHR subjects, 18 made a transition to psychosis. Psychopathology was investigated with the Structured Interview for Prodromal Syndromes, Bonn Scale for the Assessment of Basic Symptoms and GAF-score. The follow-up period of the study was three years. The UHR+T group showed more social anhedonia and withdrawal, more bizarre thinking and a lower GAF score at baseline than the UHR+NT group. In agreement with the results of Cannon et al. [Cannon, T.D., Cadenhead, K., Cornblatt, B., Woods, S.W., Addington, J., Walker, E., Seidman, L.J., Perkins, D., Tsuang, M., McGlashan, T., Heinssen, R., 2008. Prediction of Psychosis in Youth at High Clinical Risk: A Multisite Longitudinal Study in North America. Arch. Gen. Psychiat. 65 (1) 28-37.], our study indicates that severity of specific symptoms at baseline is related to transition to psychosis in UHR subjects. These findings may contribute to a more accurate prediction of a first psychotic episode. Furthermore, symptoms that are increased at baseline in the UHR+T group could be a focus of cognitive behavioural therapy in the UHR period.
Schizophrenia Research, 2002
We investigated the relationship between the P300, neuropsychological test performance and sympto... more We investigated the relationship between the P300, neuropsychological test performance and symptomatology in recentonset schizophrenic patients (n 45) to gain insight into underlying mechanisms of abnormal P300 in schizophrenia. The P300 was recorded in two sessions with an intermission of ®ve minutes, at the midline frontal, central and parietal electrode site. P300 amplitude and latency were compared with those obtained in 25 controls. Twenty patients were treated with olanzapine and 19 patients with risperidone. P300 amplitude was smaller and latency longer in patients than in controls. In the patient group, parietal P300 amplitude reduction was related to poorer performance on neuropsychological tests of memory. Frontal P300 amplitude reduction was related to impaired selective attention. In patients with negative symptomatology, P300 amplitude was reduced in the second P300 session compared with the ®rst. Patients on risperidone demonstrated a smaller parietal P300 amplitude than patients using olanzapine. Reduced parietal P300 amplitude could signify a dysfunction in the continuous memory updating of current events. Negative symptomatology may be associated with a time dependent decrease in neuronal ®ring, as indicated by reduced P300 amplitude in the second P300 session. q
Schizophrenia Bulletin, 2002
Consecutively admitted patients with recent-onset schizophrenia disorders (n = 56) were interview... more Consecutively admitted patients with recent-onset schizophrenia disorders (n = 56) were interviewed about their awareness of mental disorder at first occurrence of psychotic symptoms, their views about the necessity of psychiatric treatment, their perception of the role of others in initiating psychiatric treatment, and suggestions they might have about getting treatment started at an earlier point in time. About 57 percent of the patients had at least some awareness of having a mental disorder at onset of psychotic symptoms, and 61 percent of the sample believed psychiatric help was unnecessary prior to the start of psychiatric treatment. A majority of the patients (91%) perceived others to be essential in initiating treatment. Most patients (82%) thought that no change is needed on the part of professional caregivers in order to facilitate early treatment. Some awareness of mental disorder at onset was related to a shorter duration of untreated psychosis (DUP). Delaying treatment until patients themselves become aware of the need for treatment may enlarge DUP. Keywords: First episode schizophrenia, illness onset, attitudes of patients, insight, duration of untreated psychosis. Schizophrenia Bulletin, 28(3):431-442,2002.
Psychopharmacology, 2002
Rationale: Subjective experience of antipsychotic drugs is relevant for medication compliance and... more Rationale: Subjective experience of antipsychotic drugs is relevant for medication compliance and quality of life. There is, however, sparse knowledge about the assessment of subjective experience. Objectives: To examine the internal consistency, test-retest reliability, sensitivity to medication change and concurrent validity of two test instruments: the Subjective Well-Being Under Neuroleptics (SWN) and the Subjective Deficit Syndrome Scale (SDSS). Methods: Both instruments were used at admission and after 6 weeks of medication stabilization in 105 consecutively admitted patients diagnosed with DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edn) diagnoses of recent-onset schizophrenia, schizophreniform disorder or schizoaffective disorder. Results: Almost all patients were capable of reproducing their subjective experience in a consistent way both before and after medication stabilization. The internal consistency of both instruments was high. The test-retest reliability was high if medication was not changed, especially for the SWN. The SWN was sensitive for changes in medication and dosage. The short form of the SWN (SWN-20 items) had comparable psychometric qualities to the original instrument (SWN-38 items). The concurrent validity of the SWN and the SDSS was good, indicating that both tests measure the same concept. Conclusions: The assessment of subjective experience with the SWN (both versions) may be used in evaluating differential effects of anti-psychotics and dose on subjective well-being.
Sexual dysfunction and hormonal changes in first episode psychosis patients on olanzapine or risperidone
Psychoneuroendocrinology, 2009
Atypical antipsychotics interfere with central and peripheral neurotransmitter systems and with h... more Atypical antipsychotics interfere with central and peripheral neurotransmitter systems and with hormonal production. In this study we compared the effect of olanzapine and risperidone on hormonal state and sexual function (by using the Questionnaire for Sexual Dysfunction, QSD) in 40 patients with a first episode psychosis. Results were compared to those of 34 healthy controls. Patients using risperidone had significant higher prolactin levels than patients using olanzapine. Patients using olanzapine had significantly higher 17beta-estradiol levels than patients using risperidone. Overall satisfaction with sexuality was less in patients compared to controls, but not different between patients using olanzapine and those using risperidone. Problems with sexual arousal were significantly higher in patients using olanzapine compared to patients using risperidone. A significantly higher frequency of problems with ejaculation and problems with insensibility of genitals were found in patients compared to healthy controls. We found no relation between medication, prolactin and 17beta-estradiol levels, frequency of sexual activity, overall satisfaction with sexuality and any of the 18 sexual dysfunctions we investigated. Our results suggests that sexual dysfunction in patients with first episode psychosis might occur despite normal prolactin levels. Also, sexual dysfunction is highly prevalent in healthy controls. Awareness should be raised of potential sexual problems in young adults.
Psychological Medicine, 2010
Background. Cognitive impairment is considered to be a core characteristic of schizophrenia. The ... more Background. Cognitive impairment is considered to be a core characteristic of schizophrenia. The relationship between psychosis and cognitive deterioration, however, remains unclear. This longitudinal study investigated the neuropsychological functioning of patients before and after their first psychotic episode. Cognitive functioning of participants who later developed a psychosis was compared to that of people at ultra-high risk (UHR) for psychosis who did not develop psychosis at follow-up and healthy controls.
Psychological Medicine, 2010
White matter connectivity and psychosis in ultra-high-risk subjects: A diffusion tensor fiber tracking study
Psychiatry Research: Neuroimaging, 2010
This study assessed with diffusion tensor imaging (DTI) whether ultra-high-risk subjects who late... more This study assessed with diffusion tensor imaging (DTI) whether ultra-high-risk subjects who later develop a psychotic disorder (UHR-P) show abnormalities in association white matter fiber tracts as compared to UHR subjects who do not convert to psychosis (UHR-NP) and healthy controls. Participants comprised 17 male UHR subjects and 10 male healthy controls, who received baseline DTI scans before clinical follow-up. The uncinate and arcuate fasciculi, anterior and dorsal cingulate, and subdivisions of the corpus callosum were calculated and visualized, and tract-specific measurements were performed. At 24-month follow-up seven UHR subjects had developed a first psychotic episode. Fractional anisotropy in baseline DTI scans, including left-right asymmetry measures, did not differ between the groups. Thus, DTI measures of these association white matter tracts were not biological markers of psychosis in our UHR sample. Abnormalities of these fiber tracts may develop around or after onset of psychosis. However, further DTI studies in UHR subjects are needed in larger samples.
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Papers by Peter M. A. J. Dingemans