The HAM-D(6) and the MES did fulfil criteria for unidimensionality while the HAM-D(17) did not. Therefore, the extended use of the HAM-D(17) in drug trials may be questioned.
The consistency of the Hamilton Depression Scale (HDS) as a measure of the severity of depressive states has been examined when the scale was used weekly during a trial when imipramine. By use of logistic models (Rasch) the consistency of the HDS has been considered across patient-variables as age, sex, plasma levels of imipramine, and diagnosis. The results showed that the original 17-item HDS was without adequate consistency, i.e. the total score of the sample of items was no one-dimensional measure of depressive states. However, a melancholia subscale of the HDS contained items the total of which can be used to compare patients quantitatively, although in some part of the analysis one of these items showed ceiling effect. It was concluded that the melancholia subscale (containing the items depressed mood, guilt, work and interests, retardation, psychic anxiety, and general somatic symptoms) can form the basis for further improvements in the field of quantitative rating scales for depressive states.
The normal-exposed Hellmann raingauge only catches about 85% of the true precipitation on yearly basis. This is mainly due to aerodynamic effects. A statistical model analysing the ratio of the daily amounts of precipitation measured at ground level and at standard height is set up for describing this influence. Corrections due to liquid and solid precipitation and three different kind of exposures are presented. Further the statistical errors on the corrections are estimated.
Wind induced errors in precipitation measurements result in systematic deficits, which are particularly large when the precipitation falls as snow combined with high wind speed. The actual magnitude of the deficit can amount to more than half of the true precipitation. In order to correct for these deficits, newly developed statistical models for solid and mixed precipitation are presented; together with a correction model for liquid precipitation presented earlier, a comprehensive system of correction models is now available. Statistical errors on the corrections are estimated.
One of best validated findings in schizophrenia research is the association between blockade of dopamine D2 receptors and the effects of antipsychotics on positive psychotic symptoms. The aim of the present study was to examine correlations between baseline striatal D2/3 receptor binding potential (BPp) values and treatment outcome in a cohort of antipsychotic-naïve first-episode schizophrenia patients. Additionally, we wished to investigate associations between striatal dopamine D2/3 receptor blockade and alterations of negative symptoms as well as functioning and subjective well-being. Twenty-eight antipsychotic-naïve schizophrenia patients and 26 controls were included in the study. Single-photon emission computed tomography (SPECT) with [123I]iodobenzamide ([123I]-IBZM) was used to examine striatal D2/3 receptor BPp. Patients were examined before and after 6 weeks of treatment with the D2/3 receptor antagonist amisulpride. There was a significant negative correlation between striatal D2/3 receptor BPp at baseline and improvement of positive symptoms in the total group of patients. Comparing patients responding to treatment to nonresponders further showed significantly lower baseline BPp in the responders. At follow-up, the patients demonstrated a negative correlation between the blockade and functioning, whereas no associations between blockade and negative symptoms or subjective well-being were observed. The results show an association between striatal BPp of dopamine D2/3 receptors in antipsychotic-naïve first-episode patients with schizophrenia and treatment response. Patients with a low BPp have a better treatment response than patients with a high BPp. The results further suggest that functioning may decline at high levels of dopamine receptor blockade.
A total of 97 patients, who participated in two studies on the relationship between the clinical effect and plasma levels of imipramine and clomipramine, were examined for improvement curves by use of weekly ratings on the Hamilton Depression Scale (HDS). Although we confirmed that our six-item HDS subscale, in contrast to the total 17-item HDS, was a one-dimensional measure of depression, the Rasch analysis showed that the weekly improvement in subscale scores only applied to the individual patient, i.e. an average improvement curve for a group of depressed patients is an abstraction to which the individual curves cannot be transferred. Our results indicate, however, that when the subscale scores are transformed into three clinical categories of depression: no, mild (minor), moderate/-severe (major) they could be described by a common improvement curve for all patients. This is illustrated by the percentage of patients who, week to week, changed from major to minor or no depression, or from minor to no depression. We found no specific improvement pattern for imipramine or clomipramine which could be used diagnostically. There is reason to assume that patients completing a controlled trial necessarily will follow a monotonic improvement curve, and the improvement pattern of all patients fulfilling the entry criteria should, therefore, always be reported. The present study thus indicates that calculation of average improvement curves is neither clinically nor statistically meaningful, and should be replaced by measures of changes in number of patients in different main severity categories, or by the final rating score. No difference in outcome between imipramine and clomipramine was shown neither on the subscale nor on the 17-item HDS.
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