G M van der Molen

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The immediate effects of a single inhalation of a 35% CO2 mixture in oxygen were examined in 12 patients with panic disorders and 11 normal control subjects. Compared to a placebo air inhalation, the CO2 inhalation provoked short-lived autonomic panic symptoms in both patients and normals; it also elicited high subjective anxiety in patients with panic(More)
The effect of lactate infusion on pCO2 and respiration rate was studied in two differently instructed groups of healthy volunteers in a double-blind, placebo-controlled, cross-over study. Both groups showed a significant decrease in alveolar pCO2 after lactate but not after placebo. This was accompanied by an increase in respiration rate in those subjects(More)
Endurance and changes in electromyogram (EMG) power spectra were investigated during a fatiguing static contraction at 50% of the maximum EMG amplitude in two jaw-elevator muscles (masseter and temporalis) and five facial muscles (frontalis, corrugator supercilii, zygomaticus major, orbicularis oris, and buccinator). Relatively high endurance was found in(More)
Biological changes due to the menstrual cycle may account for the fact that fears are not equally distributed between the sexes. In a differential, classical conditioning paradigm, women in premenstrual phase of their menstrual cycles were compared with a control group of women at other points in their cycles except within seven days before menstruation.(More)
The authors compared the subjective reaction of 13 panic patients and eight control subjects to a 35% CO2 challenge, a treatment known to produce physical symptoms comparable to those of natural or lactate-induced panic, and to placebo treatment (inhalation of air). They found that patients had higher placebo scores than control subjects, patients tended to(More)
Experimental research has demonstrated that CO2 inhalation provides a valid laboratory model for acute panic. Earlier studies employed CO2/O2 mixtures that were not only hypercapnic but also hyperoxic, raising the question of the relative contribution of the hyperoxidity. A comparison between a hypercapnic/hyperoxic mixture (35% CO2/65% O2) and a(More)
Psychological and physiological reactions to a failure experience were studied in type A males and type B males both during task and no-task periods. Before failure was induced, no difference in sympathetic reactivity was found, neither during task nor during no-task periods. After an experience of failure type A subjects showed higher sympathetic(More)
Conditioning models have been very helpful in the understanding of the etiology and maintenance of anxiety. Such laboratory models, however, leave unexplained why in many cases of naturally occurring anxiety, as in the case of agoraphobia, the fear responses do not extinguish. Literature on experimental anxiety provocation suggests that a systemic alkalosis(More)