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Biomedical subjects

K Schruers

Publications and source records attributed to K Schruers.

14 recordsLinked to original sources
PubMed2005

Anxiety sensitivity in children of panic disorder patients.

Anxiety sensitivity (AS), which refers to the tendency to interpret anxiety-related bodily sensations as having potentially harmful somatic, psychological or social consequences, has been proposed as a vulnerability factor for the development of panic disorder (PD). The current study examined the anxiety sensitivity levels in children of parents with panic disorder. Children of panic disorder patients (n = 68) and children of healthy parents (n = 68) filled out the Childhood Anxiety Sensitivity Index, while parents completed the Anxiety Sensitivity Index. Children of parents with panic disorder did not display higher levels of anxiety sensitivity than children of healthy parents. Furthermore, no association between anxiety sensitivity levels of parents with panic disorder and their children was found. Anxiety sensitivity is not clearly manifest in children of parents with panic disorder and might be a developing vulnerability factor that may increase towards late adolescence or early adulthood.

Adolescent↗
PubMed2005

The influence of ethanol infusion on the effects of 35% CO2 challenge. A study in panic disorder patients and healthy volunteers.

UNLABELLED: Alcohol and panic disorders co-occur at a rate that exceeds chance significantly. Early experimental work suggests that alcoholic subjects, compared to non-alcoholics, are less sensitive to sodium lactate and that alcohol intake reduces the response to a 35% CO(2) challenge in Panic Disorder patients. The present study documents the direct pharmacological effect of ethanol infusion on CO(2) induced panic. METHODS: According to a placebo-controlled, double-blind, randomized, cross-over design 10 drug free panic disorder patients and 16 healthy volunteers underwent a 35% CO(2) challenge after intravenous infusion of a moderate dose of ethanol on one test day and of placebo on another test day. RESULTS: Compared to the placebo condition, the effect of the CO(2) challenge was significantly smaller after ethanol infusion (P = 0.041). DISCUSSION: A moderate dose of ethanol decreased the response to a 35% CO(2) without inducing pre challenge sedation. CONCLUSION: The results comfort earlier findings of a direct pharmacological effect of ethanol on panic.

Adult↗
PubMed2005

Obsessive-compulsive disorder: a critical review of therapeutic perspectives.

OBJECTIVE: Obsessive-compulsive disorder (OCD) is a chronic disabling disease with profound implications for social functioning. Thirty per cent of all patients with OCD show insufficient improvement with state-of-the-art treatment. Conventional treatment and alternative treatment options for this population were investigated. METHOD: A selective review of the relevant scientific literature on OCD treatment and treatment resistance was conducted. RESULTS: In addition to serotonin reuptake inhibitors (SRIs) and cognitive-behavioural therapy, alternative monotherapies, SRI augmentation strategies with a variety of drugs and electroconvulsive therapy have shown results in individual cases, but no conclusive evidence has been found in placebo-controlled trials. While studies investigating neurosurgery for refractory OCD show positive results, most of these studies have methodological shortcomings. CONCLUSION: Novel approaches currently under investigation that have shown promising effects for treatment-resistant OCD include SRI augmentation with atypical antipsychotics and chronic deep brain stimulation, a new surgical technique. Placebo-controlled trials for both treatment options will be needed to confirm preliminary findings.

Antidepressive Agents↗
PubMed2004

Growth of knowledge in psychiatry and behavioural sciences in a problem-based learning curriculum.

PURPOSE: To evaluate the effectiveness of undergraduate medical education in the domains of psychiatry and behavioural sciences, we examined the growth of knowledge in those disciplines in a 6-year, problem-based learning (PBL) curriculum. Psychiatry and behavioural sciences are taught in the 4 preclinical years and in the psychiatric clerkship. The integrative nature of this PBL curriculum led us to hypothesise that the knowledge growth curves for these disciplines are similar and show a steady upward trend throughout the curriculum. METHODS: All items pertaining to psychiatry and behavioural sciences in the progress tests administered in the period from September 1993 through May 2001 were identified. For those items, the percentage of correct scores in the 6 year groups were considered a multivariate observation reflecting knowledge growth across the 6-year programme. RESULTS: Knowledge growth for psychiatry and behavioural sciences increased significantly, from 12% to 59% and from 28% to 60%, respectively, between Year 1 and the end of Year 6. Apparently, students know more about behavioural sciences than about psychiatry when they enter medical school, but this difference vanishes in the last 2 years of training. Moreover, the growth curves for psychiatry and behavioural sciences started to level off after Years 3 and 4, respectively, with no additional significant growth in any of the later years. CONCLUSIONS: Psychiatry and behavioural sciences showed different patterns of knowledge growth and the 2 growth curves levelled off in Years 5 through 6. Because a student-centred, horizontally and vertically integrated PBL curriculum is aimed at effecting steady growth in knowledge in all disciplines, the slowdown in growth in the later years was among the reasons for initiating a major curricular innovation in 2001.

Behavioral Sciences↗
PubMed2002

The effects of acute exercise and high lactate levels on 35% CO2 challenge in healthy volunteers.

OBJECTIVE: To test the possible antipanic effects of acute exercise in healthy volunteers exposed to an inhalation of 35% CO2 challenge. METHOD: Twenty healthy subjects in a randomized separate group design, performed exercise in a bicycle ergometer reaching >6 mm of blood lactate and a control condition of minimal activity in the same fashion with no lactate elevation. Immediately afterwards an inhalation of a vital capacity using a mixture of 35% CO2/65% O2 through a mask was given on both conditions. RESULTS: Subjects under the exercise condition reported less panic symptoms than controls after a CO2 challenge on the diagnostic statistical manual-IV (DSM-IV) Panic Symptom List but no difference on the Visual Analogue Anxiety Scale. CONCLUSION: Subjects under the exertion condition had lactate levels comparable with those of lactate infusions but an inhibitory rather than accumulative effect was seen when combined with a CO2 challenge.

Adult↗
PubMed2000

Effects of tryptophan depletion on carbon dioxide provoked panic in panic disorder patients.

Results of an earlier study in healthy volunteers suggest that the serotonergic system is involved in anxiety-related mechanisms. We studied the influence of tryptophan depletion on the response to a 35% carbon dioxide challenge. Twenty-four panic disorder patients received a mixture of amino acids, either with or without tryptophan, under double-blind conditions. There was a significant increase in anxiety as well as in neurovegetative symptoms in the depletion group, compared to the placebo condition. Furthermore, when we compare the results of the placebo group with earlier panic provocation studies, it also seems that a balanced amino acid mixture might have a protective effect against a panic provocation. We conclude that the panic-enhancing effect of tryptophan depletion as well as the potential protective effect of tryptophan administration in panic disorder patients can be explained by the Deakin-Graeff theory of anxiety.

Adult↗
PubMed2000

10 microg CCK-4 premedication and 35% CO2 challenge in healthy volunteers.

1. The purpose of the study was to confirm whether a subthreshold dose of CCK-4 would enhance the vulnerability of healthy subjects to a 35% carbon dioxide challenge. 2. 40 subjects, with no prior or present psychiatric disorder and in good physical health were challenged with a vital capacity breath of a 35% carbon dioxide 65% oxygen mixture, immediately after an intravenous injection of 10 microg CCK-4 or placebo, according to a random order, double blind, separate group design. 3. Subjects reported significantly less anxiety and panic symptoms upon carbon dioxide after premedication with CCK-4 than after placebo. 4. CCK-4 and carbon dioxide seem to inhibit rather than enhance each other's effects, possibly through an effect on different neurobiological systems.

Adult↗
PubMed2000

Effects of low-dose cholecystokinin on respiratory function in healthy volunteers.

Injection of high doses of cholecystokinin tetrapeptide (CCK-4), a recent experimental model for panic, causes panic attacks and respiratory stimulation, a key feature of panic, in healthy volunteers. However, it has not yet been established whether respiratory stimulation is specifically linked to panic or merely an effect of arousal in general. Results of the present study show that respiratory stimulation is not merely linked to higher arousal and suggest a link between CCK-provoked panic and respiratory stimulation.

Anxiety↗
PubMed1999

Effect of CCK-4 on a 35% carbon dioxide challenge in healthy volunteers.

1. The purpose of this study was to determine whether a subthreshold dose of CCK-4 would enhance the vulnerability of healthy subjects to a 35% carbon dioxide challenge. 2. 27 subjects, with no prior or present psychiatric disorder and in good physical condition were challenged with a vital capacity breath of a 35% carbon dioxide mixture, immediately after an intravenous injection of 5 micrograms CCK-4 or placebo, according to a random order double blind crossover design. 3. Subjects reported significantly less panic symptoms upon carbon dioxide after premedication with CCK-4 than after placebo. 4. Both CCK-4 and carbon dioxide may act on the same neuronal pathways, but seem to inhibit rather than potentiate each other effects.

Adult↗
PubMed1998

Experimental pathophysiology of panic.

In this article, we review how the knowledge of the pathophysiology of panic disorder has expanded, with special emphasis on laboratory models using lactate and carbon dioxide challenges. Experiments in the late 1960s revealed that lactate infusion can induce panic attacks. A prominent feature of these attacks is hyperventilation. Because lactate infusion induces a metabolic alkalosis, one would rather expect a compensatory hypoventilation. For years hyperventilation was thought to be causally linked to panic, but it has since been proven to be a symptom rather than a cause of panic attacks. Similarly, it is not hypocapnia but hypercapnia that has proven to be capable of provoking panic attacks. Carbon dioxide challenges are comparable to lactate infusion in the degree to which they meet the criteria for an ideal model of panic disorder. Experiments with carbon dioxide in first-degree relatives of panic disorder patients and in monozygotic twins support the idea of a constitutional predisposition to panic disorder. Of the various other agents that have been used to trigger panic attacks, cholecystokinin seems particularly promising as a valid laboratory model of panic disorder and may provide valuable data regarding the mechanism of panic attacks. The false suffocation alarm theory, proposed by Klein, is an integrative hypothesis that may account for a large number of the laboratory as well as clinical observations.

Carbon Dioxide↗