Laboratory screening for electrolyte abnormalities and anemia in bulimia nervosa: a controlled study

OBJECTIVE

Abnormal eating patterns and recurrent purging behaviors can result in significant medical complications. The purpose of this study was to assess the frequency of abnormalities in clinical laboratory tests in patients with bulimia nervosa who reported being otherwise in good health.

METHODS

Subjects included nonhospitalized women (N = 74) who met criteria for bulimia nervosa outlined in the 3rd Rev. ed. of the Diagnostic and Statistical Manual of Mental Disorders. They also reported use of self-induced vomiting and/or laxatives as compensatory behaviors (purging subtype). The control group (N = 110) included female volunteers with no history of a psychiatric disorder. All subjects reported being in good medical health, were medication free, and were in a normal weight range. Blood samples were analyzed in the hospital clinical laboratory.

RESULTS

Compared with controls, patients showed more frequent occurrence of low values for serum potassium (6.8% vs. 0.9%; p <.05) and chloride (8.1% vs. 0.9%; p <.02). Electrolyte abnormalities occurred most often in patients with frequent bulimic episodes. Study groups did not differ significantly in frequency of abnormal hemoglobin concentrations.

DISCUSSION

These results help to clarify the expected frequency of electrolyte abnormalities in individuals with bulimia nervosa who report otherwise good medical health. The substantial frequency of hypokalemia and hypochloremia underscores the importance of an appropriate medical assessment for individuals with this disorder.

Bioavailability of pure isoflavones in healthy humans and analysis of commercial soy isoflavone supplements

The pharmacokinetic behavior of naturally occurring isoflavones has been determined for the first time in healthy adults. We compared plasma kinetics of pure daidzein, genistein and their beta-glycosides administered as a single-bolus dose to 19 healthy women. This study demonstrates differences in the pharmacokinetics of isoflavone glycosides compared with their respective beta-glycosides. Although all isoflavones are efficiently absorbed from the intestinal tract, there are striking differences in the fate of aglycones and beta-glycosides. Mean time to attain peak plasma concentrations (t(max)) for the aglycones genistein and daidzein was 5.2 and 6.6 h, respectively, whereas for the corresponding beta-glycosides, the t(max) was delayed to 9.3 and 9.0 h, respectively, consistent with the residence time needed for hydrolytic cleavage of the glycoside moiety for bioavailability. The apparent volume of distribution of isoflavones confirms extensive tissue distribution after absorption. Plasma genistein concentrations are consistently higher than daidzein when equal amounts of the two isoflavones are administered, and this is accounted for by the more extensive distribution of daidzein (236 L) compared with genistein (161 L). The systemic bioavailability of genistein [mean AUC = 4.54 microg/(mL x h)] is much greater than that of daidzein [mean AUC = 2.94 microg/(mL x h)], and bioavailability of these isoflavones is greater when ingested as beta-glycosides rather than aglycones as measured from the area under the curve of the plasma appearance and disappearance concentrations. The pharmacokinetics of methoxylated isoflavones show distinct differences depending on the position of the methoxyl group in the molecule. Glycitin, found in two phytoestrogen supplements, underwent hydrolysis of the beta-glycoside moiety and little further biotransformation, leading to high plasma glycitein concentrations. Biochanin A and formononetin, two isoflavones found in one phytoestrogen supplement, were rapidly and efficiently demethylated, resulting in high plasma genistein and daidzein concentrations typically observed after the ingestion of soy-containing foods. These differences in pharmacokinetics and metabolism have implications for clinical studies because it cannot be assumed that all isoflavones are comparable in their pharmacokinetics and bioavailability. An analysis of 33 phytoestrogen supplements and extracts revealed considerable differences in the isoflavone content from that claimed by the manufacturers. Plasma concentrations of isoflavones show marked qualitative and quantitative differences depending on the type of supplement ingested. These studies indicate a need for improvement in quality assurance and standardization of such products.

Decreased serum leptin in bulimia nervosa

The eating disorder bulimia nervosa has been associated with impaired satiety, decreased resting metabolic rate, and abnormal neuroendocrine regulation. Preclinical studies suggest that such alterations could be associated with impaired leptin function. Thus, the goal of this study was to assess whether leptin function is decreased in bulimia nervosa. Serum leptin levels measured in women with bulimia nervosa (n = 18) and in women who had maintained stable recovery from bulimia nervosa (n = 15) were compared with values in healthy female controls (n = 20). Subjects were studied during the follicular phase of their menstrual cycle after an overnight fast and bed rest. Baseline serum samples were analyzed for leptin concentration by RIA. Subject groups were matched for age and body weight. Analysis of covariance, adjusting for percent body fat, demonstrated abnormally low serum leptin levels in the bulimia nervosa group (P: = 0.02), with a trend toward an inverse correlation between frequency of binge episodes and serum leptin concentration (P: < 0.1). Additionally, the remitted patient group demonstrated abnormally low leptin values (P: = 0.01). These results are consistent with the hypothesis that decreased leptin function may be associated with alterations in eating patterns, metabolic rate, and neuroendocrine regulation in bulimia nervosa.

Serotonin function following remission from bulimia nervosa

Abnormal serotonergic regulation in bulimia nervosa is thought to contribute to recurrent binge eating, depressed mood, and impulsivity. To follow-up on previous studies showing decreased neuroendocrine responses in symptomatic patients, this study assessed serotonin-mediated prolactin responses in individuals who had remitted from bulimia nervosa. Subjects included 21 women with a history of bulimia nervosa and 21 healthy female controls, as well as an additional comparison group of 19 women with current bulimia nervosa. Placebo-controlled neuroendocrine response studies utilized a single oral dose (60 mg) of the indirect serotonin agonist d,l-fenfluramine. For the bulimia nervosa remitted group, the fenfluramine-stimulated elevation in serum prolactin concentration was not significantly different from the response in healthy controls, but was significantly larger than the response in patients with current bulimia nervosa (p < .01). These findings suggest that diminished serotonergic neuroendocrine responsiveness in bulimia nervosa reflects a state-related abnormality. The results are discussed in relationship to recent reports indicating that some alterations in central nervous system serotonin regulation may persist in symptomatically recovered individuals.

Salivary gland enlargement and elevated serum amylase in bulimia nervosa

BACKGROUND

Clinical reports have described salivary gland enlargement in bulimia nervosa, particularly in patients with elevated serum amylase concentration. The goal of the current study was to provide a controlled comparison of salivary gland size in patients with bulimia nervosa and healthy volunteers.

METHODS

Subjects included 17 women with bulimia nervosa and 21 healthy female control subjects. Dimensions of the parotid and submandibular salivary glands were estimated by ultrasonography. Blood samples for amylase measurement were obtained after overnight fast.

RESULTS

Parotid gland size was enlarged 36% in patients with bulimia nervosa in comparison to control subjects (p < .01). For the patient group, salivary gland size was significantly correlated with frequency of bulimic symptoms and with serum amylase concentration.

CONCLUSIONS

These results provide new quantitative data demonstrating increased salivary gland size in bulimia nervosa. Further studies are needed to evaluate factors responsible for salivary gland enlargement and hyperamylasemia in this disorder.

Research update on serotonin function in bulimia nervosa and anorexia nervosa

The extent to which dysregulation of serotonin function in the central nervous system may contribute to core symptoms in patients with bulimia nervosa and anorexia nervosa is currently an area of intensive psychobiological investigation. Preclinical and clinical studies have demonstrated the involvement of the neurotransmitter serotonin in the regulation of food intake, suggesting that impaired serotonin-mediated satiety signals could contribute to patterns of recurrent binge eating. Other symptom patterns in patients with eating disorders, including mood dysregulation, impulsivity, and obsessionality, as well as therapeutic response to serotonergic agents, suggest involvement of serotonergic pathways. With a primary focus on serotonin function, this article reviews clinical studies of neuroendocrine and behavioral response to pharmacological challenges, levels of neurotransmitter metabolite in cerebrospinal fluid, and platelet studies. Controlled clinical trials involving pharmacological treatment with serotonergic medications are summarized. Considerations for future research are discussed.

Toward a more clinically valid approach to therapy research

Despite the advances in psychotherapy outcome research, findings are limited because they do not fully generalize to the way therapy is conducted in the real world. Research's clinical validity has been compromised by the medicalization of outcome research, use of random assignment of clients without regard to appropriateness of treatment, fixed number of therapy sessions, nature of the therapy manuals, and use of theoretically pure therapies. The field needs to foster a more productive collaboration between clinician and researcher; study theoretically integrated interventions; use process research findings to improve therapy manuals; make greater use of replicated clinical case studies; focus on less heterogeneous, dimensionalized clinical problems; and find a better way of disseminating research findings to the practicing clinician.

Decreased serotonin function in bulimia nervosa

BACKGROUND

Evidence that serotonin-active antidepressant medications decrease binge eating in patients with bulimia nervosa has fueled interest in the hypothesis that abnormal serotonergic neurotransmitter function contributes to symptoms of the disorder. To evaluate this hypothesis, we employed pharmacological challenge testing to compare serotonin function in patients with bulimia nervosa and healthy controls.

METHODS

Neuroendocrine response patterns were compared for 15 nonhospitalized, medication-free, normal-weight women with bulimia nervosa and 14 age-matched healthy female controls. Behavioral assessment included ratings of eating disorder symptoms, depression, and anxiety. Serotonergic response patterns were assessed by measuring the increase in serum prolactin concentration during 5 hours following single-dose, oral administration of 60 mg of d,l-fenfluramine hydrochloride (Pondimin).

RESULTS

For patients with bulimia nervosa, the fenfluramine-stimulated increase in serum prolactin concentration was significantly less than for controls. Within the patient group, the frequency of binge eating episodes during the 4 weeks prior to the study exhibited a significant inverse correlation with serotonin-stimulated prolactin secretion.

CONCLUSION

Our study provides new evidence that impaired central nervous system serotonergic responsiveness may contribute to the onset or maintenance of abnormal eating patterns in patients with bulimia nervosa.

The effects of dieting on plasma tryptophan concentration and food intake in healthy women

Although many people diet, relatively few dieters are successful in maintaining weight loss. The extent to which dieting behavior might dampen satiety responses normally mediated by the neurotransmitter serotonin remains uncertain. This study tested the hypothesis that dieting behavior decreases the availability of plasma tryptophan (TRP) and the ratio of TRP to other branched-chain amino acids (BCAA) that compete for entry into the central nervous system (CNS). This effect could diminish the CNS concentration of TRP, the amino acid precursor for serotonin synthesis, thus interfering with serotonin-mediated influences on food intake. Using a fixed-order design, 15 healthy, normal-weight women were studied longitudinally during an ad lib dietary intake phase and subsequent reduced-calorie diet phase. Physiological and behavioral measures were collected at baseline, at the end of the ad lib-intake phase, and at the end of the 4-week study diet phase. Food intake was measured by a single-item test meal. Plasma TRP and TRP: sigma BCAA significantly decreased following the study diet compared to baseline (p < 0.05). Change in TRP and TRP: sigma BCAA significantly correlated with decrease in body weight (p < 0.01). No significant relationship was observed between postdiet change in TRP or TRP: sigma BCAA ratio and postdiet change in test meal food intake, with covariation for weight loss. The observed decreases in plasma TRP and TRP: sigma BCAA extend previous reports suggesting that dieting behavior may diminish central serotonin function through a reduction in precursor availability.

Psychotherapy practice and research. Repairing a strained alliance

Although the gap between psychotherapy practice and research has been present for some time, recent pressures for accountability from outside the system-managed health care and biological psychiatry-necessitate that we take steps to close this gap. One such step has been for psychotherapy researchers to specify a list of empirically validated therapies. However, as researchers who also have a strong allegiance to clinical practice, we are concerned that the conceptual and methodological constraints associated with outcome research may become clinical constraints for the practicing therapist. We firmly believe that, more than ever before, the time is ripe for us to develop a new outcome research paradigm that involves an active collaboration between researcher and practicing clinician.

Medications in the treatment of eating disorders

Effective planning for medication treatment in patients with bulimia nervosa and anorexia nervosa is based on a comprehensive clinical assessment, including a careful review of comorbid psychiatric disorders and response to treatments for previous episodes of the disorder. Although most patients with bulimia nervosa are offered a trial of psychotherapy, significant results of controlled trials have contributed to an increased role for medications in the treatment of patients with this disorder. Pharmacologic treatment of anorexia nervosa has similarities to that of treatment-resistant depression, with the clinician turning to open trials and clinical reports for clues to rational management. As described in this article, considerations of potential side effects and medical complications are likely to play an important role in guiding the choice of medication used for treatment of patients with eating disorders.

Psychotherapy practice and research. Repairing a strained alliance

Although the gap between psychotherapy practice and research has been present for some time, recent pressures for accountability from outside the system-managed health care and biological psychiatry-necessitate that we take steps to close this gap. One such step has been for psychotherapy researchers to specify a list of empirically validated therapies. However, as researchers who also have a strong allegiance to clinical practice, we are concerned that the conceptual and methodological constraints associated with outcome research may become clinical constraints for the practicing therapist. We firmly believe that, more than ever before, the time is ripe for us to develop a new outcome research paradigm that involves an active collaboration between researcher and practicing clinician.

Peer review by nursing research committees in hospitals

With the increasing amount of nursing research conducted in clinical settings, the value of peer review by nursing research committees (NRCs) in hospitals has come under greater scrutiny. Research facilitation has been the prevailing paradigm of NRCs for several decades. Reports of activities by NRCs in the literature appear to indicate a shift in that paradigm. The presence of clinical nurses with expert knowledge and advanced academic degrees who are serving as intra- and interdisciplinary scientific reviewers are leading a shift in the paradigm of NRCs toward activities that strengthen nursing science and nurse scientists. Eight strategies to support NRCs as review bodies for scientific merit are recommended.

Dimensions of response to antidepressant agents in bulimia nervosa: a review

Many patients suffering from bulimia nervosa benefit from treatment with antidepressant medication. Nurses, like other mental health clinicians, tend to assess the effectiveness of a pharmacologic agent in patients with bulimia nervosa by the decline in the frequency of binge eating episodes. Clinical descriptions and research reports suggest the possibility of additional behavioral dimensions of treatment responsiveness, although the extent to which associated behaviors or symptoms improve is not well documented. This paper examines 16 placebo-controlled pharmacological trials in patients with bulimia nervosa to evaluate a range of potential measures of response to antidepressant intervention.

Comparison of the effects of amino acid mixture and placebo on plasma tryptophan to large neutral amino acid ratio

To assess the possible role of altered central serotonin function in psychiatric disorders, investigators have utilized pharmacological challenge testing with an amino acid mixture to decrease blood tryptophan concentration and, indirectly, brain serotonin levels. The aim of this pilot study was to assess the effectiveness of a modified amino mixture, administered in capsule form, in decreasing plasma tryptophan levels. Studies were conducted in six healthy, medication-free female volunteers. Following double-blind, randomized, cross-over design, subjects received on separate days capsules containing a tryptophan-free amino acid mixture (31.5 grams) or lactose placebo. Over the six hours following amino acid administration, plasma tryptophan concentrations decreased to 21% of baseline values, while the tryptophan/large neutral amino acid ratio decreased to 6% of baseline. Subjects reported minimal symptoms of nausea or other side effects following amino acid administration. The results suggest that the modified amino acid mixture may be useful in assessing behavioral responses to acute tryptophan depletion challenge testing.

Elevated sweet taste pleasantness ratings in bulimia nervosa

Recent studies suggest that some patients with bulimia nervosa may experience elevated pleasantness responses to sweet taste. This study explored possible associations between symptoms patterns and pleasantness ratings for sucrose solutions in bulimic patients. Subjects included 15 women meeting DSM III-R criteria for narrowly defined bulimia nervosa (no history of other eating disorder); five patients with current bulimia nervosa and a past history of anorexia nervosa; and 20 healthy age-matched female controls. Subjects ate a standardized breakfast prior to the morning study visit. Sucrose-water solutions (0% to 40% sucrose) were rated for sweetness intensity and pleasantness. Patients with narrowly defined bulimia nervosa showed significantly higher pleasantness ratings for 40% sucrose solutions than controls and patients with a history of anorexia nervosa. Pleasantness ratings were not significantly correlated with frequency of binge eating or purging behaviors. These results extend previous evidence for altered sweet taste pleasantness responses in bulimia nervosa, and for differences in eating-related behaviors between patients with narrowly defined bulimia nervosa vs. those with past anorexia nervosa.

Hypnotizability, dissociation, and bulimia nervosa

This study examined the levels of hypnotizability and dissociation in an outpatient sample of 17 normal-weight bulimic women and 20 healthy controls. Bulimic patients were significantly more hypnotizable than controls (p < .003) and scored higher on a self-report scale of dissociative experiences (p < .02). The results of measures of hypnotizability and dissociation showed a significant positive correlation in the combined subject group. These results are consistent with previous reports on hospitalized patients and college students and suggest that psychological factors associated with hypnotizability might play a role in the etiology and treatment of bulimia nervosa.

Hypnotizability, dissociation, and bulimia nervosa

This study examined the levels of hypnotizability and dissociation in an outpatient sample of 17 normal-weight bulimic women and 20 healthy controls. Bulimic patients were significantly more hypnotizable than controls (p < .003) and scored higher on a self-report scale of dissociative experiences (p < .02). The results of measures of hypnotizability and dissociation showed a significant positive correlation in the combined subject group. These results are consistent with previous reports on hospitalized patients and college students and suggest that psychological factors associated with hypnotizability might play a role in the etiology and treatment of bulimia nervosa.

The use of challenge studies in biobehavioral nursing research

With the rapid growth of biotechnology, developments in psychopharmacology, and advances in the understanding of biobehavioral relationships, psychiatric nursing is presented with exciting new opportunities for research related to clinical practice. Although challenge strategies have been developed largely within the medical subspecialties, this article describes the application of pharmacological challenge testing to assist in the understanding of biobehavioral relationships pertinent to psychiatric nursing. This article presents examples of challenge strategies and their relevance to clinical practice. The use of the challenge method in psychiatric nursing research and future directions are discussed.

Impulsivity ratings in bulimia nervosa: relationship to binge eating behaviors

Although impulsive behavioral patterns are often described by patients with bulimia nervosa, there has been little formal evaluation of the relationship between impulsivity and eating-related symptomatology in this disorder. In this controlled outpatient study, ratings on the Barratt Impulsivity Scale were significantly elevated in 20 women with bulimia nervosa in comparison to 20 healthy female volunteers. Frequency of binge eating episodes was not significantly correlated with impulsivity ratings. Although these results indicate increased prevalence of impulsive behavioral style in patients with bulimia nervosa, impulsivity per se does not appear to be a predictor of symptom severity as reflected in frequency of bulimic episodes.

Alexithymia ratings in bulimia nervosa: clinical correlates

Previous reports indicate that some patients with eating disorders have alexithymic characteristics, including affect deficit states and paucity of imagination. This study evaluated whether nonhospitalized patients with bulimia nervosa had elevated ratings of alexithymia in comparison to age-matched controls, and whether severity of bulimic symptoms was correlated with elevations in alexithymia ratings. Because alexithymia may be secondary to concurrent depression, this study was limited to patients with bulimia nervosa who were free of major depression. The authors compared alexithymia ratings for nonhospitalized normal weight women meeting DSM-III-R criteria for bulimia nervosa (N = 20) to healthy female volunteers (N = 20), utilizing the Toronto Alexithymia Scale (TAS) as the primary assessment instrument. Subjects also completed standardized rating scales for bulimic symptoms, depression, and anxiety. Alexithymia rating scale scores were significantly higher for patients with bulimia nervosa than for controls. In comparison to controls, patients had significant elevations on TAS factors reflecting affect deficit states, but normal scores for factors reflecting imagination and abstract thinking. Frequency of binge eating or purging behaviors was not correlated with alexithymia ratings. These data indicate that some patients with bulimia nervosa have alexithymic characteristics. Affect dysregulation was more prominent than limitation in fantasy or metaphorical thought. Additional studies are needed to assess whether presence of alexithymic characteristics may be predictive of response to treatment in patients with bulimia nervosa.