Prolactin response to d-fenfluramine in obsessive-compulsive patients, and outcome of fluvoxamine treatment

Are 5-HT3 antagonists effective in obsessive-compulsive disorder? A systematic review of literature

OBJECTIVE

The purpose of this literature database search-based review was to critically consider and evaluate the findings of literature focusing on efficacy and safety of 5-HT3 antagonists in the treatment of obsessive-compulsive disorder (OCD), so as to test whether preclinical data match clinical therapeutic trials.

DESIGN

The PubMed database has been searched for papers on 5-HT3 antagonists and OCD in humans and for animal models of OCD and 5-HT3 receptors.

RESULTS

Of the clinically tested 5-HT3 receptor antagonists, ondansetron has been used to treat OCD in five therapeutic studies, whereas granisetron only in one recent trial. Both showed some efficacy in open studies and superiority to placebo in double-blind studies, along with fair safety. No animal OCD model directly implicated 5-HT3 receptors.

CONCLUSIONS

Overall, results indicate some utility, but the available literature is too scanty to allow for valid conclusions to be drawn. The mismatch between animal models of obsessive-compulsive disorder and clinical data with 5-HT3 antagonists needs more clinical data to ensure that it is not an artefact.

Acute hormonal changes after IV citalopram and treatment response in OCD

RATIONALE

Serotonergic pharmacological challenges have failed to produce consensual results in patients with obsessive-compulsive disorder (OCD), suggesting a heterogeneous 5-hydroxytryptamine (5-HT) activity in this disorder.

OBJECTIVES

The aim of this study was to compare the neuroendocrine response to a serotonergic challenge in OCD patient responders (RP) and nonresponders (NR) to serotonin reuptake inhibitors treatment and healthy volunteers.

MATERIALS AND METHODS

Thirty OCD treatment NR, 30 RP, and 30 controls (CN) matched for sex and age were included. Each subject received 20 mg of intravenous citalopram. Prolactin, cortisol, and growth hormone plasma concentration were measured at times-20, 0, 20, 40, 60, 80, 100, 120, 140, and 160 min after the onset of citalopram infusion.

RESULTS

Citalopram did not induce anxiety or OCD symptoms in patients. Citalopram was associated with stronger prolactin response in the CN group (maximal percentage variation [max%Delta] = 65.76 +/- 105.1) than in NR (max%Delta = 17.41 +/- 31.06) and RP groups (max%Delta = 15.87 +/- 31.71; p = 0.032; Friedman chi (2) = 6.87; df = 2). On the other hand, cortisol response did not differ between CN and RP groups and was blunted in the NR group (NR max%Delta = 20.98 +/- 58.14 vs RP max%Delta = 47.69 +/- 66.94; CN max%Delta = 63.58 +/- 88.4; p = 0.015; Friedman chi (2) = 8.60; df = 2).

CONCLUSIONS

Compared to CN, both treatment RP and NR patients showed blunted prolactin response to citalopram, but only NR patients showed an attenuated cortisol response, suggesting a more disrupted central serotonergic transmission in this group.

Biological predictors of treatment response in affective illness

Attempts to identify biological response predictors generally have met with limited success, particularly where the goal is to develop clinically useful indices. This article reviews the biological approaches to predicting treatment response, beginning with neuroendocrine studies and electroencephalogram analysis and concluding with structural and functional neuroimaging. The article describes the designs of typical studies to aid in interpreting their results and concludes by addressing some of the problems and limitations associated with these approaches and suggesting future directions for this research.

Neuroendocrine predictors of response to intravenous clomipramine therapy for refractory obsessive-compulsive disorder

The current study examines the neuroendocrine response to intravenous clomipramine (IV CMI) in oral CMI-resistant obsessive-compulsive disorder (OCD) patients on day 1 and day 14 of treatment to identify predictors of response. Forty-four OCD patients with an inadequate response or poorly tolerant to oral CMI were begun at 25 mg IV CMI, increasing to 250 mg by day 10, and continuing on that dose to day 14. On day 1, plasma levels of prolactin (PRL), growth hormone (GH), and cortisol were obtained immediately before the 25 mg IV infusion, and at five 30-minute time points after the infusion. On day 14, hormonal samples were obtained in a similar fashion. Response was assessed by the Clinical Global Impressions (CGI). Low PRL(MAX) to IV CMI and low cortisol levels overall on day 1 were both significantly associated with clinical response at day 14. An overall increase in growth hormone (GH) secretion during the day 14 testing was associated with positive response. A pronounced PRL response to IV CMI on day 14 was exhibited by the nonresponders, whereas a smaller and later but significant increase in PRL was noted in the responders. The findings suggest that in this sample of oral CMI-resistant patients with OCD, neuroendocrine measures derived from pharmacological challenge with IV CMI are capable of distinguishing IV CMI treatment responders from nonresponders. The limitations of IV CMI as a specific probe of serotonin function are discussed.

Pharmacological treatment of childhood obsessive-compulsive disorder: from theory to practice

Discusses pharmacological treatment of childhood obsessive-compulsive disorder (OCD), chronic and underrecognized psychiatric condition that affects up to 2% to 3% of children and adolescents. Research in OCD in children, including neuropharmacology, brain imaging, genetics, and clinical phenomenology, informs current views of OCD pathophysiology. Contemporary research supports the notion of a dysregulation in serotonin subsystems in the central nervous system, with target areas of dysfunction including basal ganglia and orbitofrontal cortex. Pharmacotherapy, along with cognitive-behavioral approaches, constitutes the indicated treatment for childhood OCD. Pharmacological treatment is best guided by a phenomenological understanding of the type of obsessions and compulsions, the intensity and frequency of their presentation with attention to behavioral reinforcements, and psychosocial factors that affect the course of the disease. Serotonin-enhancing agents, such as fluoxetine, fluvoxamine, paroxetine, and sertraline and citalopram (SSRIs) are first-line pharmacological agents, whereas refractory symptoms can be treated by augmentation with neuroleptics or other agents. Clomipramine is as effective as the SSRIs but its use may be accompanied by increased side effects. Genetic factors probably influence susceptibility to OCD as well as response to treatment, and the elucidation of these and other risk factors will be important elements in the future understanding and treatment of this disorder.

Fenfluramine challenge in anxious children

The study objective was to determine if serotonergic challenge with oral racemic fenfluramine would differentiate between childhood anxiety disorders in comparison to normal controls. Subjects were 24 children with anxiety diagnoses (DSM-IIIR) by structured interview, and 14 normal controls (ages 7 - 14 years) matched for age and sex. All subjects were given a standard challenge dose of d,1-fenfluramine (1 mg/kg) followed by serial assessments of cardiovascular, neurohormonal, and mood parameters over a five hour period. In response to fenfluramine, controls demonstrated increases in subjective anxiety and systolic blood pressure relative to anxious subjects. Fenfluramine was safely tolerated and did not induce panic symptoms in any subject. Exaggerated prolactin response to fenfluramine differentiated an obsessive - compulsive disorder (OCD) subset from both controls and other anxiety disorders. Fenfluramine challenge differentiates anxious children from healthy controls by elevated anxiety ratings and systolic blood pressure in controls. Increased prolactin response to fenfluramine discriminates children with obsessive - compulsive disorder from both healthy children and children with other anxiety diagnoses. As adults with OCD appear to demonstrate a blunted prolactin response to fenfluramine challenge, the serotonin pathways involved may differ between 'early' and 'late' onset disorder, or the serotonin substrates tapped by this challenge may change over time. Copyright 2000 John Wiley & Sons, Ltd.

[Obsessive-compulsive disorder, frontostriatal system and the effect of the serotonergic system]

OBJECTIVES

Focal issues of recent research on obsessive-compulsive disorders have been the involvement of the frontostriatal system in the patho-physiology, as well as the manner of effect and efficacy of the serotonin reuptake inhibitors that unfold their specific efficacy in the frontostriatal system. The course of treatment among adolescent inpatients with obsessive-compulsive disorder was analyzed with regard to the medications used and their effects upon the course of treatment.

METHODS

The data for all adolescents with obsessive-compulsive disorder admitted as inpatients to the Hospital for Child and Adolescent Psychiatry and Psychotherapy in Mannheim since 01.01.1990 were analyzed with regard to medication and the parameters for course and outcome.

RESULTS

Five patients dropped out of treatment, five patients received no medication, eight received sulpiride, ten were treated with clomipramine, and three with fluvoxamine. The average length of inpatient stay was longer for the groups treated with sulpiride and clomipramine than for the group that received no medication, but equivalent for these two medication groups. The success of treatment for obsessive-compulsive disorder was rated as higher in these two groups than in the group without medication. On sulpiride, patients gained weight and exhibited fatigue and increased levels of prolactin. On clomipramine, half of the patients exhibited cardiac side effects.

CONCLUSIONS

This small, nonrandomized medicated sample analyzed under non-double-blind conditions shows no difference in the efficacy of clomipramine and sulpiride under post hoc analysis. Rather, the side effects that occurred in patients on clomipramine indicate a more frequent use of SSRI to increase compliance as regards medication intake.

Fenfluramine challenge test predicts outcome in pharmacological treatment of patients with functional gastrointestinal disorder

We investigated if response to the fenfluramine challenge test could predict outcome in 47 nonpsychiatric patients with chronic functional gastrointestinal disorder (FGD) treated with mianserin, a drug closely related to mirtazepine, or placebo. Sixty milligrams of fenfluramine was given orally in the morning on nonfasting basis. Serum cortisol (COR) and prolactin (PRL) were analyzed at baseline, and after 120, 180, and 240 minutes. Patients were then randomized into a 7-week double-blind treatment trial with mianserin or placebo. Response to treatment with mianserin (76% vs.18% for placebo) was closely linked to a high increase in PRL and COR following a fenfluramine challenge test (positive predictive power=72%). Adding length of illness history increased both positive and negative predictive power to 92%. Our results indicate that the fenfluramine challenge test may be a potentially useful tool to identify nonpsychiatric subjects with FGD, who will most likely respond to treatment with a combined alpha2 and 5HT-2 and -3 antagonist.

Selective serotonin reuptake inhibitors and neuroendocrine function

Selective serotonin (5-HT) reuptake inhibitors (SSRIs) are effective drugs for the treatment of several neuropsychiatric disorders associated with reduced serotonergic function. Serotonergic neurons play an important role in the regulation of neuroendocrine function. This review will discuss the acute and chronic effects of SSRIs on neuroendocrine function. Acute administration of SSRIs increases the secretion of several hormones, but chronic treatment with SSRIs does not alter basal blood levels of hormones. However, adaptive changes are induced by long-term treatment with SSRIs in serotonergic, noradrenergic and peptidergic neural function. These adaptive changes, particularly in the function of specific post-synaptic receptor systems, can be examined from altered adrenocorticotrophic hormone (ACTH), cortisol, oxytocin, vasopressin, prolactin, growth hormone (GH) and renin responses to challenges with specific agonists. Neuroendocrine challenge tests both in experimental animals and in humans indicate that chronic SSRIs produce an increase in serotonergic terminal function, accompanied by desensitization of post-synaptic 5-HT1A receptor-mediated ACTH, cortisol, GH and oxytocin responses, and by supersensitivity of post-synaptic 5-HT2A (and/or 5-HT2C) receptor-mediated secretion of hormones. Chronic exposure to SSRIs does not alter the neuroendocrine stress-response and produces inconsistent changes in alpha2 adrenoceptor-mediated GH secretion. Overall, the effects of SSRIs on neuroendocrine function are dependent on adaptive changes in specific neurotransmitter systems that regulate the secretion of specific hormones.

Seasonal variation in plasma prolactin response to D-fenfluramine in healthy subjects

To assess dynamically a seasonal variation in the functioning of the central serotonin (5-HT) system, we investigated the prolactin (PRL) response to the specific serotonergic agent D-fenfluramine (D-FEN) in the different seasons of the year. Thirteen healthy women and 11 healthy men (six for each season), aged 20-50 years, received PO 30 mg D-FEN and placebo, according to a randomized double-blind design. As compared to placebo, D-FEN induced a clear-cut increase in plasma PRL levels in all the seasons; this response was higher in fall than in spring and summer (p < .01 and < .05, respectively). In all the subjects, as a group, the hormone response to the 5-HT probe was inversely correlated with the body weight and age. These results document a seasonal variability in the PRL response to D-FEN, which suggests a seasonal fluctuation in central 5-HT transmission in healthy humans.

Prolactin response to d-fenfluramine is blunted in people with anorexia nervosa

BACKGROUND

Several studies have explored serotonin (5-HT) transmission in people with anorexia nervosa, but their results have been inconsistent.

METHOD

According to a double-blind placebo-controlled design, plasma prolactin response to the specific serotonergic probed d-fenfluramine was investigated in 10 under weight and two normal-weight women with anorexia, and in 12 age-matched healthy females. Eating-related psychopathology, depressive and obsessive--compulsive symptoms, and aggressiveness were measured by appropriate rating scales.

RESULTS

Compared with healthy control subjects, the women with anorexia showed reduced baseline prolactin and oestrogen levels and increased basal cortisol concentrations. The prolactin response to d-fenfluramine was blunted and did not correlate with psychopathological measures.

CONCLUSIONS

These results support a dysfunction of 5-HT transmission in anorexia nervosa. This dysfunction does not seem to be related to concomitant depressive or obsessive--compulsive symptoms or to the level of aggressiveness of the patients.