Biomedical subjects

P M Dingemans

Publications and source records attributed to P M Dingemans.

At least 19 recordsLinked to original sources

PubMed2002

Clinical and neuropsychological correlates of the P300 in schizophrenia.

We investigated the relationship between the P300, neuropsychological test performance and symptomatology in recent-onset 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 five 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 first. 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 firing, as indicated by reduced P300 amplitude in the second P300 session.

Adult↗

PubMed2001

Significantly reduced docosahexaenoic and docosapentaenoic acid concentrations in erythrocyte membranes from schizophrenic patients compared with a carefully matched control group.

BACKGROUND: Fatty acid research in schizophrenia has demonstrated an altered cell membrane phospholipid metabolism. Erythrocyte membrane phospholipid composition closest reflects that of neuronal membranes. METHODS: (Poly)(un)saturated fatty acid concentrations were measured in the erythrocyte membranes of 19, consecutively admitted, medicated young schizophrenic patients and then compared with matched control subjects. Psychiatric symptomatology was rated with the Positive and Negative Symptom Scale and Montgomery-Asberg Depression Rating Scale. Because diet, hormones, and cannabis influence fatty acid metabolism, we included these factors in our study. RESULTS: The most distinctive findings concerned the omega-3 series: C22:5 omega-3, C22:6 omega-3 (docosahexaenoic acid), and the sum of omega-3 fatty acids were significantly decreased. Interestingly, C20:4 omega-6 (arachidonic acid) was not lowered. In the omega-9 series, higher levels of C22:1 omega-9 and lower levels its elongation product, C24:1 omega-9 (nervonic acid), were found. Interestingly, the other arm of the desaturation-elongation sequence of C18:1 omega-9, C20:3 omega-9, was lower in patients. The total omega-9 fatty acid levels were also lower in patients. CONCLUSIONS: Significant differences in erythrocyte fatty acid composition were found. The differences were not due to diet or hormonal status and could not be explained by the medication or cannabis use. No consistent pattern emerged from the different fatty acid abnormalities and the clinical symptom scores.

Adolescent↗

PubMed2001

Dopamine transporter density in young patients with schizophrenia assessed with [123]FP-CIT SPECT.

Disturbances in the dopamine (DA) system are thought to play a major role in schizophrenia. Amphetamine-induced release of endogenous DA is shown to be enhanced in schizophrenia, as is striatal [18F]FDOPA uptake in the striatum. It is not clear if the density of DA neurons is altered in schizophrenia. By studying the DA transporter with [123I]FP-CIT single photon emission computed tomography (SPECT), the density of nigrostriatal dopaminergic cells can be studied. Using [123I]FP-CIT SPECT, DA transporter density in the striatum was studied in 36 young patients with schizophrenia. Ten patients were antipsychotic (AP)-naive, 15 were treated with olanzapine, eight with risperidone and three were AP-free. A control group of 10 age-matched volunteers was included. Striatal [123I]FP-CIT binding was not significantly different between AP-naive patients (2.87), patients treated with olanzapine (2.76), patients treated with risperidone (2.76), AP-free patients (2.68) and controls (2.82) (F=0.07,p=0.98). Unexpectedly, striatal [123I]FP-CIT binding in females was significantly higher than in males (3.29 and 2.70, respectively; t=-2.56, p=0.014).Concluding, functional changes in the dopaminergic system in schizophrenia are not likely to be reflected in a change in DA transporter density. Moreover, DA transporter density does not seem to be altered by AP medication.

Adult↗

PubMed2001

Social functioning and the course of early-onset schizophrenia: five-year follow-up of a psychosocial intervention.

BACKGROUND: Schizophrenia implies severe social impairments. Since the treatment of patients with schizophrenia shifted from long-term hospital admissions to community services, research on social functioning has become increasingly important. AIMS: Follow-up assessment of social functioning in young patients with schizophrenia during a 5-year period after intervention. METHOD: During intervention, families were randomised into two conditions: standard intervention and standard plus family intervention. RESULTS: Although no differential treatment effect with regard to the course of the illness was found, patients from the standard plus family intervention condition stayed for fewer months in institutions for psychiatric patients than patients from the standard intervention condition. CONCLUSIONS: Family intervention has helped parents to support their children, thereby diminishing institutional care.

Activities of Daily Living↗

PubMed2000

Component structure of the positive and negative syndrome scale (PANSS) in patients with recent-onset schizophrenia and spectrum disorders.

RATIONALE: Earlier studies have examined the symptom dimensions of the PANSS (Positive And Negative Syndrome Scale) in patients with chronic schizophrenia. Results have suggested that three to eight component solutions best explain underlying symptom dimensions. OBJECTIVES: To examine the component structure of the PANSS and the MADRS (Montgomery Asberg Depression Rating Scale) in young patients with recent-onset schizophrenia and related disorders and the correlations between the components of both instruments. METHODS: Symptomatology was measured in 138 patients with recent-onset schizophrenia, by administering the PANSS and the MADRS. RESULTS: Principal component analysis of the PANSS revealed five components: a positive, negative, depression, agitation-excitement and disorganisation component. The MADRS only showed one component. A high correlation was found between the depression component of the PANSS and the overall score of the MADRS (p=0.87, P<0.001). A moderate correlation was found between the PANSS negative component and the overall score of the MADRS (p=0.51, P<0.001). CONCLUSIONS: The data suggest a five component structure of the PANSS. The depression component of the PANSS seems to be a valid way of assessing depression in patients with recent-onset schizophrenia.

Adolescent↗

PubMed2000

Subjective experience and striatal dopamine D(2) receptor occupancy in patients with schizophrenia stabilized by olanzapine or risperidone.

OBJECTIVE: The authors' goal was to study the relationship between subjective experience during treatment with olanzapine or risperidone and dopamine D(2) receptor occupancy in stabilized patients with schizophrenia. METHOD: Subjective experience, psychopathology, and extrapyramidal symptoms were assessed, and D(2) receptor occupancy was determined with [(123)I]iodobenzamide single photon emission computed tomography, in 22 patients whose schizophrenia was stabilized by olanzapine or risperidone. RESULTS: Subjective experience, depression, and negative symptoms were related to dopamine D(2) receptor occupancy, but extrapyramidal symptoms were not. CONCLUSIONS: These results provide preliminary evidence that negative subjective experience is related to high D(2) receptor occupancy. Longitudinal study is required because this relationship may have implications for dosing strategies.

Adolescent↗

PubMed1998

Early detection and intervention in schizophrenia.

During the course of schizophrenia, symptoms tend to increase at the highest rate during the first 5 years of the disease. Moreover, 10% of suicides by schizophrenic patients occur within the first 10 years of schizophrenia being diagnosed. These facts emphasize the importance of early intervention to improve the course of the disease before further deterioration. The use of psychosocial interventions and drug management programmes, in addition to maintenance antipsychotic medication, reduces the risk of psychotic relapse. Continuity of care from inpatient to outpatient treatment also significantly improves outcome, largely as a result of better drug compliance. It appears, however, that the addition of a behavioural family intervention alone to a standard programme offers little additional benefit. The benefits of intervention programmes last only as long as the programme, and patients should continue with such intensive treatment strategies for at least the duration of the critical phase. Under these circumstances, very mild psychotic complaints may be recognized at an early stage so that treatment can begin even earlier, further increasing the chance of an optimal long-term outcome. Further studies of early intervention and relapse prevention are required to support these findings.

Antipsychotic Agents↗

PubMed1997

A quantitative measure for expressed emotion.

The items of the Five Minute Speech Sample, an instrument to elicit relatives' expressed emotion, were investigated in a follow-up study of 120 parents of adolescents with recent-onset schizophrenia. A composite scale was constructed using Mokken scale analysis. From the 9 available items, 6 formed a unidimensional and cumulative scale. This scale was applicable for the total parent group, as well as for fathers and mothers separately. A second scale of 2 items did not meet the criteria for the Mokken model completely and was applicable for the parent group as a whole, but not for fathers and mothers as separate groups. The configuration of the subscales as found with the Mokken scale analysis was comparable with the results of principal component analysis. A quantitative measure may detect smaller differences in expressed emotion than the dichotomous index and expands the possibilities for statistical tests.

Adolescent↗

PubMed1997

Patient attributes and expressed emotion as risk factors for psychotic relapse.

In the context of a prospective, controlled treatment study, contrasting family interventions with individual treatment, the role of expressed emotion (EE) as a predictor of relapse was examined in patients with recent-onset schizophrenia and related disorders (n = 97). EE was compared with 13 predictor variables. The variables, taken from EE and family intervention studies, related to demography, premorbid functioning, present and past illness history, and comorbid substance abuse. Psychotic relapse was operationalized with a conservatively measured relapse criterion, composed of monthly ratings based on the Brief Psychiatric Rating Scale and on clinical judgment during the 12 months of outpatient treatment. Of the 14 predictor variables entered in stepwise survival analyses, 6 variables had probable predictive power on the conservative relapse criterion. These variables were entered in a Cox regression model. EE turned out to be the major predictor of relapse in the overall sample (hazard ratio [HR] 4.90; confidence interval [CI] 1.05-22.92). This finding remained when only patients with a first psychotic episode (p = 0.02) and patients in the individual treatment condition (p = 0.001) were examined. Cannabis abuse was the major predictor of relapse in patients with high-EE families (HR 4.27; CI 1.12-16.29).

Adolescent↗

PubMed1997

Parental communication deviance: its stability and the effect of family treatment in recent-onset schizophrenia.

The influence of a behavioural family treatment on parental communication deviance (CD) was investigated in a longitudinal treatment study. Subjects were the parents of young patients with recent-onset schizophrenia or related disorders. Parents and patients were randomly assigned to one of two treatment conditions: individual out-patient treatment or a combination of individual out-patient and family treatment. Parental CD was assessed with the Thematic Apperception Test (TAT) both at the start of the out-patient treatment and after completion of treatment 1 year later. Most families had high levels of CD, a finding which is in agreement with previous CD studies. These high CD levels remained stable over the 12-month period. Family treatment was not effective in influencing the level of CD. The findings suggest that high CD is a stable trait-marker of parents, and they support the notion that high levels of CD may precede the onset of serious psychotic disorders. Studies with more chronic patients are needed to replicate the findings.

Adult↗

PubMed1997

The relationships between expressed emotion, affective style and communication deviance in recent-onset schizophrenia.

The relationships between expressed emotion (EE), affective style (AS) and communication deviance (CD) were studied during hospitalization and after discharge. EE was measured with both the Camberwell Family Interview (CFI) and the Five-Minutes Speech Sample (FMSS). The study subjects were patients with recent-onset schizophrenia and related disorders, who were consecutively admitted to an in-patient unit for adolescents, and their parents. The results revealed that CFI/EE was significantly correlated with AS criticism scores during hospitalization, but did not predict AS scores after discharge. FMSS/EE correlated significantly with AS criticism when both measures were administered after discharge. During hospitalization, FMSS/EE was not significantly correlated with AS. No consistent relationship was found between CD and both affective factors (EE and AS). It is concluded that EE and AS overlap with regard to level of criticism when both measures are administered over a short period of time and independent of the time of assessment. In addition, the results indicate that affective and communication factors identify independent family attributes.

Adolescent↗

PubMed1996

Does the MMPI-168 exaggerate psychotic pathology?

Three scoring versions of the MMPI, scored on the same protocol, were compared in a multivariate design with 198 psychiatric patients. The MMPI-168 schizophrenia scale had a statistically higher elevation than the Dutch and American scoring versions. This makes MMPI-168 profiles more often "schizophrenic" than other scoring versions. The MMPI-168 systematically overscores the presence of "psychotic" code types, 45% of all protocols. Implications of the findings are discussed.

Cross-Cultural Comparison↗

PubMed1996

Symptoms, cognitive and social functioning in recent-onset schizophrenia: a longitudinal study.

The relationships among symptoms, cognitive functioning and social functioning were investigated in patients with schizophrenia over a period of 15 months. Patients with a mood disorder, a normal control group and a sample of parents of the schizophrenic patients also completed the cognitive tests. In the schizophrenia sample, only disorganisation was correlated with cognitive performance, which was interpreted as further evidence that disorganisation is a separate symptom dimension of schizophrenia. Against expectations, with two of three measurements no significant correlations were found between negative symptoms and cognitive performance. With these two measurements, however, a curvilinear association between negative symptoms and cognitive performance was observed, suggesting that negative symptoms are not a unitary concept. Finally, tentative evidence could be obtained for speed of information processing and selective attention as markers for vulnerability, although the latter is not specific for schizophrenia.

Adult↗

PubMed1995

Component structure of the expanded Brief Psychiatric Rating Scale (BPRS-E).

The component structure of the expanded Brief Psychiatric Rating Scale (BPRS-E) was analyzed in a sample (n = 150) of consecutively admitted general psychiatric inpatients and compared with a group (n = 97) of adolescent patients with schizophrenia spectrum diagnoses. A stable five-component solution, of which four were interpretable, was found across groups. The component scales of the 24-item version of the BPRS had good internal consistency, allowed better coverage of schizophrenia and affective symptoms than the 18-item version but did not distinguish the schizophrenia diagnostic subgroups. The implications of the findings are discussed.

Adolescent↗

PubMed1995

Dimensions and subtypes of recent-onset schizophrenia. A longitudinal analysis.

A sample of young patients with schizophrenia was studied in a longitudinal design to investigate the stability of an earlier reported four-dimensional symptom model (positive symptoms, negative symptoms, disorganization, and depression). Symptoms were measured in an acute phase soon after hospitalization, in a remitted stage 3 months later, and in a "mixed" phase 1 year after the second assessment. A different factor structure was found at each measurement, but a stable four-dimensional structure could be defined that closely resembled the factor structure of the first assessment. The symptom dimensions were uncorrelated, except disorganization and depression. Whether meaningful subtypes could be defined using statistical criteria also was investigated. With cluster analysis, four subtypes were defined that could be characterized as follows: rapid treatment responders, slower responders, and two relapse groups. Although some indication of the validity of these subtypes was found, it is concluded that there is a high risk of creating artificial boundaries with this approach.

Adolescent↗

PubMed1994

Cannabis abuse and the course of recent-onset schizophrenic disorders.

OBJECTIVE: We sought to examine the relation between cannabis abuse and the symptomatic course of recent-onset schizophrenia and related disorders. DESIGN: A prospective cohort study over a year using monthly Brief Psychiatric Rating Scale assessments. PARTICIPANTS: Cannabis-abusing patients (n = 24) were compared with nonabusers (n = 69). Eleven patients were mild and 13 were heavy cannabis-abusing patients. RESULTS: Significantly more and earlier psychotic relapses occurred in the cannabis-abusing group (P = .03). This association became stronger when mild and heavy cannabis abuse were distinguished (P = .002). No confounding effect of other variables, eg, other street drugs, was found. In all but one patient, cannabis abuse preceded the onset of the first psychotic symptoms for at least 1 year. CONCLUSIONS: Cannabis abuse and particularly heavy abuse can be considered a stressor eliciting relapse in patients with schizophrenia and related disorders and possibly a premorbid precipitant.

Adolescent↗

PubMed1994

Relapse criteria in schizophrenic disorders: different perspectives.

Relapse and exacerbation of psychotic symptoms were investigated in a prospective study of 88 patients with recent-onset schizophrenia and related disorders. Relapse definitions were derived from expressed emotion and family intervention studies and based on the Brief Psychiatric Rating Scale (BPRS), the Present State Examination, and clinical judgment. Results indicate that research and clinical criteria represent different perspectives on relapse. Clinical criteria provide a validity check that can verify BPRS-rated changes in partially remitted patients.

Adolescent↗

PubMed1993

Symptom dimensions and cognitive and social functioning in recent-onset schizophrenia.

The relationships among symptoms, cognitive functioning and social functioning were investigated in 60 patients with recent-onset schizophrenia. Positive symptoms were unrelated to cognitive measures. Disorganization and depressive symptoms were correlated significantly with Card Sorting performance. Furthermore, only negative symptoms were correlated significantly with social functioning. These results replicate earlier studies with chronic and mixed samples, and support the validity of disorganization as a separate symptom dimension. In contrast to most previous studies, no significant correlations were found between negative symptoms and cognitive measures. However, some evidence was found for a non-linear association between negative symptoms had several cognitive measures. The variation explained by a curvilinear model was not high, but for some cognitive measures this model was clearly superior to a linear model. If replicated, this finding supports the position that cross-sectionally measured negative symptoms cannot be viewed as a unitary concept.

Adolescent↗