Tandospirone, a 5-HT1A partial agonist is effective in treating anorexia nervosa: a case series

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines update 2023 on the pharmacological treatment of eating disorders

OBJECTIVES

This 2023 update of the WFSBP guidelines for the pharmacological treatment of eating disorders (EDs) reflects the latest diagnostic and psychopharmacological progress and the improved WFSBP recommendations for the assessment of the level of evidence (LoE) and the grade of recommendation (GoR).

METHODS

The WFSBP Task Force EDs reviewed the relevant literature and provided a timely grading of the LoE and the GoR.

RESULTS

In anorexia nervosa (AN), only a limited recommendation (LoE: A; GoR: 2) for olanzapine can be given, because the available evidence is restricted to weight gain, and its effect on psychopathology is less clear. In bulimia nervosa (BN), the current literature prompts a recommendation for fluoxetine (LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1). In binge-eating disorder (BED), lisdexamfetamine (LDX; LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1) can be recommended. There is only sparse evidence for the drug treatment of avoidant restrictive food intake disorder (ARFID), pica, and rumination disorder (RD).

CONCLUSION

In BN, fluoxetine, and topiramate, and in BED, LDX and topiramate can be recommended. Despite the published evidence, olanzapine and topiramate have not received marketing authorisation for use in EDs from any medicine regulatory agency.

International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

Molecular bases of anorexia nervosa, bulimia nervosa and binge eating disorder: shedding light on the darkness

Eating-disorders (EDs) consequences to human health are devastating, involving social, mental, emotional, physical and life-threatening aspects, concluding on impairment and death in cases of extreme anorexia nervosa. It also implies that people suffering an ED need to find psychiatric and psychological help as soon as possible to achieve a fully physical and emotional recovery. Unfortunately, to date, there is a crucial lack of efficient clinical treatment to these disorders. In this review, we present an overview concerning the actual pharmacological and psychological treatments, the knowledge of cells, circuits, neuropeptides, neuromodulators and hormones in the human brain- and other organs- underlying these disorders, the studies in animal models and, finally, the genetic approaches devoted to face this challenge. We will also discuss the need for new perspectives, avenues and strategies to be developed in order to pave the way to novel and more efficient therapeutics.

The Role of Psychotropic Medications in the Management of Anorexia Nervosa: Rationale, Evidence and Future Prospects

Anorexia nervosa (AN) is a severe psychiatric disorder without approved medication intervention. Every class of psychoactive medication has been tried to improve treatment outcome; however, randomized controlled trials have been ambiguous at best and across studies have not shown robust improvements in weight gain and recovery. Here we review the available literature on pharmacological interventions since AN came to greater public recognition in the 1960s, including a critical review of why those trials may not have been successful. We further provide a neurobiological background for the disorder and discuss how cognition, learning, and emotion-regulating circuits could become treatment targets in the future. Making every effort to develop effective pharmacological treatment options for AN is imperative as it continues to be a complex psychiatric disorder with high disease burden and mortality.

Chronic treatment with tandospirone, a serotonin 1A receptor partial agonist, inhibits psychosocial stress-induced changes in hippocampal neurogenesis and behavior

BACKGROUND

The 5-hydroxytryptamine (5-HT) 1A receptors are considered a potential target for the treatment of mental and neuropsychiatric disorders. Several studies have indicated that 5-HT1A receptor agonists increase hippocampal neurogenesis, which is implicated in the action mechanism of antidepressants. However, these agents have not been applied to humans due to intolerable side effects. We recently showed that chronic administration of tandospirone, a clinically available 5-HT1A receptor partial agonist, increased hippocampal neurogenesis dose-dependently. The present study was done to determine if chronic tandospirone treatment has antidepressant potential from the standpoint of hippocampal neurogenesis and behavior.

METHODS

Male Sprague-Dawley rats were intraperitoneally administered a vehicle or tandospirone (10mg/kg) once daily for 28 days. Two weeks after starting the injections, animals were exposed to intermittent social defeat (four times over two weeks). The effects of stress and tandospirone on the rodents׳ behavior were evaluated by the Novelty-Suppressed Feeding (NSF) test. The quantification of hippocampal neurogenesis was estimated using immunostaining with Ki-67 and doublecortin (DCX).

RESULTS

Chronic tandospirone treatment reversed the psychosocial stress-induced increase in the latency in the NSF test and decrease in the density of DCX-positive cells in the dentate gyrus of the dorsal and ventral hippocampus. However, no difference in the density of Ki-67-positive cells was observed between the vehicle- and tandospirone-administered groups.

LIMITATIONS

To clarify the antidepressant potential of TDS, the other behavioral tests for depression will be required.

CONCLUSIONS

Our findings suggest that tandospirone has antidepressant potential through an inhibiting effect on stress-induced changes in hippocampal neurogenesis.

Under- to over-eating: how do serotonin receptors contribute?

In numerous pathological states, the brain can restrict food intake to a lethal level despite mounting requirements for energy as seen in adolescents with anorexia nervosa. How the brain reduces food intake to the point of death while eating is a cornerstone of survival that remains just as ‘cryptic’ as the association between anorexia and overeating. This review provides a recent snapshot of the neural underpinnings of the rewarding effects of anorexia that may compete with the adaptive decision-making process to eat, and with survival instinct. Among a plethora of factors, impaired activity of the serotonin receptors in the reward system underlies the ability of animals to self-impose food restriction, and the transition from under- to over-eating. However, the triumvirate association between serotonin, overeating and addiction appears unlikely. Considering the implication of the serotonin receptors in the hypothalamus, anorexia and bulimia nervosa could result from an impairment of a ‘synchronic activity’ between the autonomic and voluntary nervous systems.

Clinical pharmacology of eating and not eating

FDA approval of Belviq and Qsymia seems to suggest that novel pharmacological targets to modulate human abnormal eating behaviours are still to be identified. However, a renewed translational approach opens new avenues on eating disorders and female vulnerability, highlighting the role of our reward pathway in obesity and binge eating and leading to potential novel targets. Nevertheless, the 'food addiction' hypothesis is still causing much scientific debate. In this context the interest in the modulation of ghrelin pathway is still very high although, so far, only ghrelin agonism has confirmed its therapeutic potential in cachectic patients. Unfortunately, ghrelin modulation does not offer a therapeutic option for Anorexia Nervosa, where novel promising pharmacological treatments are still to be uncovered.