Biomedical subjects

D H Linszen

Publications and source records attributed to D H Linszen.

At least 19 recordsLinked to original sources

PubMed2006

[Is there any point in detecting high risk factors prior to a first psychosis?].

BACKGROUND: If schizophrenia and related disorders are diagnosed and treated early, symptoms will be less severe and the prognosis will be more favourable. There is little point in screening for schizophrenia in the general population because the illness has such a low incidence. However, we do need to find out whether it is meaningful to screen genetically impaired individuals (high risk group) and specific groups of psychiatric patients (ultra high risk group). AIM: To survey the research into the (high and ultra high) risk factors for developing a first psychosis and to find out whether it makes good sense to screen certain groups of persons. METHOD: We conducted extensive desk-research and a wide-ranging search of the literature from 1990 to 2004. The key words we used in our search were 'prodrome', 'high risk', 'ultra high risk', in conjunction with 'psychosis' and 'schizophrenia'. RESULTS: In the genetically impaired group risk factors for developing schizophrenia seem to be transient psychiatric problems in childhood, schizotypical traits, anxiety, behavioural problems in adolescence, being brought up in an unstable environment and producing deviant results in neurocognitive tests. Among the patients referred to a psychiatrist it is possible to identify a special group of patients with an ultra high risk of developing a psychosis. Within ayear 40% of patients who had mild or short-term psychotic symptoms or who were genetically impaired adolescents with decreased functioning had developed a psychosis. CONCLUSION: Screening all genetically vulnerable persons in the general population has no consequencesfor treatment. Early diagnosis by psychiatrists is certainly advisable. However, larger groups and longer studies are needed in order to demonstrate conclusively the preventive effect of interventions prior to a first psychosis.

Adolescent↗

PubMed2006

[Residual neuropsychological, structural and functional brain abnormalities after long-term cannabis use].

BACKGROUND: An important question that arises in policy discussions concerning the use of cannabis is whether the possible harmful effects of cannabis are reversible. AIM: To review studies on residual neuropsychological, structural and functional brain abnormalities that may have resulted from the long-term use of cannabis. METHOD: When we searched Medline (January 1966 - December 2003) and EMBASE (January 1988 - December 2003) using the key words 'cannabis', 'marijuana', 'neuropsychological test', 'cognition', 'CT-scan', 'MRI', 'PET', 'SPECT' and 'brain', we found 29 studies in our area of interest. We selected only those neuropsychological and functional brain imaging studies in which the patients had a controlled abstinence period longer than 98 hours. RESULTS: On the basis of six studies we concluded that there was insufficient evidence to prove conclusively that long-term cannabis use causes or does not cause residual abnormalities. The results of our review were also inconclusive whether cannabis use during adolescence may have a lasting effect on cognitive functioning and brain structure. However, we could not rule out the possibility that (1) certain cognitive and cerebral abnormalities existed in patients before cannabis use began and (2) that patients were suffering from subacute effects of cannabis. CONCLUSION: So far, research into the residual effects of cannabis use has been inadequate. Future studies should concentrate on the effect of cannabis use during early adolescence. More insight should come from longitudinal studies involving neuropsychological measurements and brain imaging before cannabis use begins. The abstinence period should be at least seven weeks.

Adolescent↗

PubMed2004

Electroconvulsive therapy for the treatment of clozapine nonresponders suffering from schizophrenia--an open label study.

OBJECTIVE: This open label study describes the efficacy of electroconvulsive therapy (ECT) as adjunctive treatment in clozapine nonresponders suffering from schizophrenia. METHOD: The results of clozapine and ECT treatment in 11 clozapine nonresponders suffering from schizophrenia are reported in terms of remission and relapse. RESULTS: Eight patients had a remission with this combination treatment. After remission of symptoms five patients had a relapse. Three of the five patients who relapsed had a second successful ECT course and remained well with maintenance ECT and clozapine. No evidence for adverse effects was found. CONCLUSION: Adjunctive ECT can be efficacious in clozapine nonresponders suffering from schizophrenia.

Adult↗

PubMed2004

Opinions of mothers on the first psychotic episode and the start of treatment of their child.

Parents, especially mothers, have a critical role in initiating psychiatric treatment for their child with first-episode schizophrenia. Knowledge of attitudes of mothers towards the illness of their child prior to psychiatric treatment and towards the start of treatment is essential for the development of interventions for reducing duration of untreated psychosis (DUP). In the present study, mothers (n = 61) of consecutively admitted patients with recent-onset schizophrenic disorders were interviewed about: their views on the nature of the symptoms at first occurrence of psychotic symptoms in their child and views on the main reason for psychiatric treatment; their perception of problems in initiating psychiatric treatment; and suggestions they might have for getting treatment started at an earlier point in time. About 57% of the mothers did not think that their child had a psychosis at first occurrence of psychotic symptoms. Most of the mothers who immediately thought that their child suffered from a psychotic disorder supposed that this disorder was caused by use of street drugs. About one-third (32.8%) of the mothers thought that the reluctance of patients to acknowledge that they needed help was the major obstacle in initiating psychiatric treatment. More than half of the mothers perceived factors related to the delivery of professional care as problems in initiating psychiatric treatment. Given the reluctance of patients to accept treatment, these problems further complicate the initiating of treatment. Mothers emphasize that a more active approach by professional caregivers could reduce treatment delay.

Adult↗

PubMed2004

A study into predictors for the speed of response to electroconvulsive therapy.

The efficacy of electroconvulsive therapy (ECT) has been firmly established in the treatment of depression. However, prediction of the speed of response to ECT is an issue that needs to be further explored. This study aims to examine the presence of predictors for the speed of response. In a retrospective chart review using 57 patients suffering from major depression who received ECT, the relation of several patient and ECT variables with the speed of response was explored. Response was defined as a drop of at least 35% in Hamilton rating scale of depression (HRSD) score from baseline after 3 or 4 ECT sessions. Patients received ECT with an aged-based stimulus dosage in a clinical setting. Multiple regression analysis showed that high baseline HRSD score and high seizure energy index (SEI) were significantly and independently associated with a rapid response. In a regression model, baseline HRSD score and SEI can be used to predict the speed of response to ECT. Rapid responders to ECT achieved remission significantly more often than slow responders did. SEI can be modified by the clinician. This offers the possibility to optimize ECT treatment.

Major Depressive Disorder↗

PubMed2002

[Schizophrenia and the 22q11 deletion syndrome].

In 10-30% of the patients with the 22q11 deletion syndrome (22q11DS), a psychosis develops in adulthood, often schizophrenia. 22q11DS is a common genetic syndrome which is associated with an interstitial deletion at chromosome 22q11. The syndrome is characterised by a variable phenotype which includes cognitive and behavioural problems, in addition to congenital heart and facial anomalies. The presence of 22q11DS represents one of the highest risk factors for the development of schizophrenia. The study of 22q11DS offers a unique opportunity to increase the understanding of the pathogenesis of schizophrenia.

Chromosomes, Human, Pair 22↗

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↗

PubMed2002

Psychometric properties of the Subjective Well-Being Under Neuroleptics scale and the Subjective Deficit Syndrome Scale.

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.

Adolescent↗

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

Dopamine transporter density in patients with tardive dyskinesia: a single photon emission computed tomography study.

RATIONALE: Tardive dyskinesia occurs frequently in schizophrenic patients chronically treated with classical antipsychotic medication. It may be caused by loss of dopaminergic cells, due to free radicals as a product of high synaptic dopamine levels. OBJECTIVE: To evaluate dopamine transporter density in the striatum in patients with tardive dyskinesia. METHODS: Striatal [123I]FP-CIT binding was measured with SPECT in seven schizophrenic patients with tardive dyskinesia and eight healthy controls. RESULTS: No significant difference was found between striatal [123I]FP-CIT binding ratios in patients with tardive dyskinesia and controls. CONCLUSIONS: This preliminary study indicates no change in striatal dopamine transporter density in schizophrenic patients with tardive dyskinesia. This finding does not support the hypothesis that tardive dyskinesia is caused by dopaminergic cell loss.

Adult↗

PubMed2001

Higher occupancy of muscarinic receptors by olanzapine than risperidone in patients with schizophrenia. A[123I]-IDEX SPECT study.

RATIONALE: In vitro data have shown anticholinergic properties of the atypical antipsychotic drug olanzapine. Substantial occupancy of muscarinic receptors may be an explanation for the low incidence of extrapyramidal side effects induced by olanzapine. OBJECTIVES: To obtain an in vivo measurement of muscarinic receptor occupancy by olanzapine compared with risperidone in patients with schizophrenia stabilised on medication. METHODS: Five patients with schizophrenia treated with olanzapine and five patients treated with risperidone were studied. Muscarinic receptor occupancy in the striatum and cortex was studied in vivo with SPECT using [123I]-IDEX as a radioligand. SPECT data were compared with those of six healthy subjects. RESULTS: Patients stabilised on olanzapine showed significantly lower mean (+/-SD) striatal and cortical (1.50+/-0.21 and 1.51+/-0.22, respectively) muscarinic receptor binding ratios of [123I]-IDEX (reflecting higher levels of muscarinic receptor occupancy) than controls (3.91+/-0.61 and 3.65+/-0.70, respectively). Furthermore, [123I]-IDEX binding ratios in patients treated with risperidone were slightly lower than controls, reaching significance only in the striatum (2.99+/-0.27 versus 3.91+/-0.61, for risperidone and controls). CONCLUSIONS: The substantial occupancy of muscarinic receptors in the striatum and cortex by olanzapine may be an explanation for the low incidence and severity of extrapyramidal side effects of this antipsychotic drug. Furthermore, it may also explain the anticholinergic side effects of olanzapine.

Adolescent↗

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

Neuropsychological and clinical correlates of antisaccade task performance in schizophrenia.

OBJECTIVES: To elucidate pathophysiologic mechanisms involved in abnormal antisaccade task performance in schizophrenia by investigating a possible relationship among antisaccade task performance, neuropsychological test results, and symptomatology in a group of young patients with recent-onset schizophrenia; to compare the effects of olanzapine and risperidone on antisaccades and reflexive saccades. BACKGROUND: Patients with schizophrenia consistently perform worse than controls on the antisaccade task in which the subject is required to inhibit a reflexive saccade to a suddenly appearing visual target and look in the opposite direction. METHODS: In 37 young (mean age 21 years), medicated patients with recent-onset schizophrenia the authors assessed antisaccades, reflexive saccades, neuropsychological test performance, and symptomatology. A subgroup of 18 patients was treated with olanzapine, and 15 patients were treated with risperidone. Reflexive-saccade and antisaccade task results were compared with those obtained in 13 control subjects. RESULTS: The antisaccade error rate was significantly higher in the patients than in the control subjects. In the patients, poor working memory function was related to increased antisaccade error rate. Severity of disorganization symptoms at intake was related to prolonged mean latency of the correct antisaccades. Patients on risperidone had a prolonged mean latency in the reflexive saccade task compared with patients using olanzapine. CONCLUSIONS: Abnormal antisaccade task performance is already present in early schizophrenia and may reflect working memory dysfunction. In future studies, medication effects should be considered in interpreting eye movement test results of patients with schizophrenia.

Adult↗

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↗

PubMed1999

Dopamine D2 receptor occupancy by olanzapine or risperidone in young patients with schizophrenia.

A crucial characteristic of antipsychotic medication is the occupancy of the dopamine (DA) D2 receptor. We assessed striatal DA D2 receptor occupancy by olanzapine and risperidone in 36 young patients [31 males, 5 females; mean age 21.1 years (16-28)] with first episode schizophrenia, using [123I]iodobenzamide (IBZM) SPECT. The occupancy of DA D2 receptors was not significantly different between olanzapine and risperidone. However, in subgroups of most prescribed doses, DA D2 occupancy was higher in the risperidone 4-mg group (79%) compared to the olanzapine 15-mg group (62%). [123I]IBZM binding ratios decreased with olanzapine dose (r = -0.551; P < 0.01), indicating higher DA D2 receptor occupancy with higher olanzapine dose. Akathisia and positive symptoms were correlated with [123I]IBZM binding ratio (r = -0.442; P < 0.01; and r = -0.360; P < 0.05, respectively). Prolactin (PRL) levels were elevated in the risperidone, but not in the olanzapine group, at comparable D2 receptor occupancy levels. In the olanzapine group, PRL levels were correlated with [123I]IBZM binding ratio (r = -0.551; P < 0.01). In conclusion, both olanzapine and risperidone induce a high striatal D2 receptor occupancy, dependent on dose and group formation. The lower incidence of prolactin elevation with olanzapine, compared to risperidone, may not be attributed to a lower D2 receptor occupancy.

Adolescent↗

PubMed1999

Clozapine and obsessions in patients with recent-onset schizophrenia and other psychotic disorders.

BACKGROUND: The increase or emergence of obsessions was compared in young patients with recent-onset schizophrenia or other psychotic disorders taking clozapine and other antipsychotic drugs. METHOD: We conducted a retrospective cohort study. Subjects were 121 consecutively admitted patients diagnosed with DSM-III-R schizophrenia, schizoaffective disorder, schizophreniform disorder, or psychotic disorder not otherwise specified. Obsessions were diagnosed according to DSM-IV criteria. RESULTS: More clozapine-treated subjects (20.6%) than subjects treated with other antipsychotic drugs (1.3%) experienced an emergence or increase of obsessions (p<.01). CONCLUSION: Use of clozapine is associated with the emergence or increase of obsessions in early-phase schizophrenia.

Adult↗

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↗