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K Ludewig

Publications and source records attributed to K Ludewig.

9 recordsLinked to original sources
PubMed2003

Dosage finding and outcome of venlafaxine treatment in psychiatric outpatients and inpatients: results of a drug utilization observation study.

BACKGROUND: Venlafaxine is an antidepressive drug with the special characteristic of inhibiting both synaptic serotonin and norepinephrine reuptake. This double action is dosage dependent, with the relatively weaker inhibition of norepinephrine becoming clinically relevant only at higher dosages. This allows treatment to be tailored towards the needs of individual patients through differential dosing. It is unknown, however, how physicians use this unique feature in prescribing venlafaxine in routine treatment. METHOD: Data from a drug utilization observation (DUO) study, including 6706 patients, are used to investigate which patient and setting variables predict dosage of venlafaxine as prescribed by psychiatrists in inpatient and outpatient settings. Treatment outcome and adverse drug reactions (ADR) were analyzed for different dosage groups. RESULTS: Treatment setting is the most important factor in predicting high (> 75 mg/day) or low (up to 75 mg/day) dosage of venlafaxine, with inpatients receiving higher dosages. Severity of illness and a history of previous treatment with major antidepressives are also related to higher dosages. Although the total rate of ADR did not increase with increased dosage, the profile of drug reactions changed. Response to therapy was better in cases of non-chronic, major depression with no treatment history of antidepressives. Additionally, increased dosage increased the likelihood of response in outpatients. In both settings, very high dosages predicted better response to venlafaxine among severely ill patients. CONCLUSION: Venlafaxine at a dosage of 75 mg/day is sufficient for the majority of cases. In extremely ill patients, higher dosages are associated with additional benefits. Therefore, a stepwise dosage regimen is suggested, with an increase of dosage to upper limits in cases of non-response before discontinuation of treatment with venlafaxine.

Adolescent↗
PubMed2002

Prepulse inhibition deficits in patients with panic disorder.

Prepulse inhibition (PPI) is an operational measure of sensorimotor gating that is reduced in several neuropsychiatric disorders that are characterized by deficits in inhibition or gating of intrusive or irrelevant stimuli. Clinically, panic disorder (PD) patients have been described as having difficulties in inhibition of responding to sensory and cognitive events. Because such difficulties may be due to failures in early stages of information processing, we examined PPI in patients with PD. Acoustic startle reactivity, habituation, and PPI (30-, 60-, 120-, 240-, and 2,000-ms interstimulus intervals) were assessed in patients with panic disorder (m/f = 10, 10) and age- and gender-matched healthy controls (m/f = 11, 10). PD patients were assessed with structured clinical interview for DSM-IV criteria with benzodiazepine treatment as an exclusion criterion. Panic disorder patients exhibited normal startle reactivity, reduced habituation, and significantly reduced PPI in the 30-, 60-, and 240-ms prepulse conditions. Within the PD group, the patients with high trait and state anxiety exhibited less PPI than patients with low trait and state anxiety. Furthermore, in PD patients, decreased PPI correlated significantly with high trait but not state anxiety. These data indicate that early stages of sensory information processing are abnormal in patients with PD. These observed deficits in PPI could reflect a more generalized difficulty in suppressing or gating information in panic disorder. The correlation between high trait anxiety and deficient PPI supports the hypothesis that sensorimotor gating abnormalities are an enduring feature of subjects with PD.

Acoustic Stimulation↗
PubMed2001

A neural network approach to the acoustic startle reflex and prepulse inhibition.

Prepulse inhibition (PPI) is the normal suppression of the startle reflex when an intense stimulus is preceded by a weak non-startling prestimulus. PPI is widely used as a model for sensorimotor gating processes and has been shown to be impaired in various neuropsychiatric disorders, including schizophrenia. We have reproduced startle-like behavior and basic PPI modifications with a neural network. The network design was constrained by the attempt (1) to use as few connections as possible and (2) to relate neuroanatomical structures to the simulated network. Performance of the network was evaluated by the behavior of the simulated motor neurons in response to prepulse and pulse stimuli presented with various lead intervals and prepulse intensities. A delayed inhibitory pathway via the pedunculopontine nucleus (PPTg) to the caudal pontine reticular nucleus was found to be a necessary but insufficient requirement to reproduce basic PPI output patterns. Additional requirements included (a) a low threshold at or below the caudal pontine reticular formation, (b) signal amplification in the inhibitory pathway and (c) prolongation of activity in the inhibitory pathway. On the grounds of the most appropriate output patterns of the simulations, we propose a mechanism of sustained activation in the PPTg due to recursive connections. Relations between stimuli, behavior (motor output) and the underlying architecture are discussed. Potentially, this modeling technique can be extended to investigate the impact of drugs and higher brain regions on PPI.

Animals↗
PubMed2001

[Depressive disorders and antidepressive therapy. A comparison of neurology practice and psychiatric clinic].

It is a question of great importance when psychiatric patients should be treated as inpatients or as outpatients. This decision depends on therapeutic as well as economic considerations. However in depression, as in other mental illnesses, many cases could reasonably be treated as in- or outpatients alike. Despite the importance of this question, there is to our knowledge no epidemiological study which compares patients in inpatient and outpatient settings within the current German medical system. 1300 inpatients and 5376 outpatients were investigated using identical methodologies within a drug utilization study of the antidepressant venlafaxine. Inpatients were found to be more severely ill and have a recurrent course of illness and higher rates of comorbidity. Outpatients more often had a chronic course. Inpatients were treated more often and with a wider variety of medication than outpatients, with the exception of phytopharmaceuticals. Venlafaxine was given in higher doses in the inpatient setting and combined more often with other psychotropic medications. Complaints of adverse drug reactions were comparable in both groups. Nausea was the most frequent, reported by 9.7% of inpatients and 15.2% of outpatients. The data show that the distribution of patients in outpatient and inpatient settings corresponds to the stepwise structure of the German health care system.

Adult↗
PubMedDate not supplied

[Restless children. An exercise in epistemic confusion].

Drawing on systemic thinking (i.e. constructivist systems theory) the paper reviews grossly the assumptions underlying childhood's restlessness ("hyperactivity") both as a distinct nosological entity and as foundation for different treatments. The phenomenon is considered, in accordance with contemporary ideas, as an interactional one. Two case examples serve as a starting point for gathering basic elements which, if put together, allow to understand this phenomenon without falling into the extremes of a mainly medical or a socionormative approach. This permits to make use of the systemic view in a manner that enables the therapist to adopt an attitude of respectful acceptance and understanding towards his/her small clients and their relatives.

Aggression↗