The reappraisal of benzodiazepines in the treatment of anxiety and related disorders

TSPO, a Mitochondrial Outer Membrane Protein, Controls Ethanol-Related Behaviors in Drosophila

The heavy consumption of ethanol can lead to alcohol use disorders (AUDs) which impact patients, their families, and societies. Yet the genetic and physiological factors that predispose humans to AUDs remain unclear. One hypothesis is that alterations in mitochondrial function modulate neuronal sensitivity to ethanol exposure. Using Drosophila genetics we report that inactivation of the mitochondrial outer membrane translocator protein 18kDa (TSPO), also known as the peripheral benzodiazepine receptor, affects ethanol sedation and tolerance in male flies. Knockdown of dTSPO in adult male neurons results in increased sensitivity to ethanol sedation, and this effect requires the dTSPO depletion-mediated increase in reactive oxygen species (ROS) production and inhibition of caspase activity in fly heads. Systemic loss of dTSPO in male flies blocks the development of tolerance to repeated ethanol exposures, an effect that is not seen when dTSPO is only inactivated in neurons. Female flies are naturally more sensitive to ethanol than males, and female fly heads have strikingly lower levels of dTSPO mRNA than males. Hence, mitochondrial TSPO function plays an important role in ethanol sensitivity and tolerance. Since a large array of benzodiazepine analogues have been developed that interact with the peripheral benzodiazepine receptor, the mitochondrial TSPO might provide an important new target for treating AUDs.

Alcohol use disorders (AUDs) affect millions of patients worldwide and result in high social and economic burdens. Although environmental factors are involved, there are clear genetic components to AUDs. Both the acute sedating effect of alcohol exposure and alcohol tolerance contribute to long term risk for alcohol dependence and addiction. Yet the genetic etiology of AUDs remains to be determined. The mitochondria play a central role in ethanol metabolism and are important in many aspects of cellular physiology such as REDOX and ROS regulation, and apoptosis. The mitochondrial outer membrane translocator protein 18 kDa (TSPO) binds the benzodiazepines and perhaps other addictive drugs, and thus may play a role in AUDs. Since Drosophila is a well-established model for ethanol-related behaviors, we have developed systems for manipulating the Drosophila tspo gene and protein. With these systems, we have discovered that neuronal TSPO controls sensitivity to ethanol sedation via ROS and caspase-mediated signaling and that systemic TSPO levels are important in the development of tolerance to repeated ethanol exposure. Given the variety of known TSPO ligands, and the common mechanisms of various abusive substances, our studies suggest that TSPO might be a promising target to combat alcoholism as well as addiction to other drugs.

Latest guidelines for the management of the anxiety disorders - a report from The International Anxiety Disorders Society Conference, Melbourne 2014

OBJECTIVE

The International Anxiety Disorders Society Conference, held in Melbourne in November 2014, enabled key researchers from Australia and internationally to interact with mental health practitioners with an interest in clinical anxiety disorders. The proceedings of previous conferences in 2006 and 2011 formed the basis of two well-received textbooks on anxiety disorders; this time we have taken up the invitation to publish the proceedings as articles in this issue of Australasian Psychiatry. At the end of the first day of the conference a lecture and linked international expert panel explored the topic of guidelines for the management of the anxiety disorders in conjunction with an engaged audience for 90 minutes - key elements of this discussion are presented here.

CONCLUSIONS

Guidelines for anxiety disorder management should be applied with caution in clinical practice settings.

Generalized anxiety disorder: psychopharmacotherapy update on a common and commonly overlooked condition

OBJECTIVE

This article provides a brief review of the practical implications of the current diagnostic conceptualisation of generalised anxiety disorder (GAD) and an update on its pharmacotherapy.

CONCLUSIONS

The diagnostic criteria for GAD need to be refined, to better reflect its clinical features and to make GAD more clinically useful. Various pharmacological agents are effective for GAD and to some extent, allow a tailored treatment approach. In addition to effectiveness, the choice of medication is influenced by the speed of therapeutic action, tolerability and habit-forming properties.

Bridging the gap between education and appropriate use of benzodiazepines in psychiatric clinical practice

More than half a century after their discovery, benzodiazepines (BDZs) still represent one of the largest and most widely prescribed groups of psychotropic compounds, not only in clinical psychiatry but also in the entire medical field. Over the last two decades, however, there has been an increased focus on the development of antidepressants and antipsychotics on the part of the pharmaceutical industry, clinicians, and researchers, with a reduced interest in BDZs, in spite of their widespread clinical use. As a consequence, many psychiatric residents, medical students, nurses, and other mental health professionals might receive poor academic teaching and training regarding these agents, and have the false impression that BDZs represent an outdated chapter in clinical psychopharmacology. However, recent advances in the field, including findings concerning epidemiology, addiction risk, and drug interactions, as well as the introduction of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition with related diagnostic changes, strongly encourage an updated appraisal of the use of BDZs in clinical practice. During a recent thematic event convened with the aim of approaching this topic in a critical manner, a group of young Italian psychiatrists attempted to highlight possible flaws in current teaching pathways, identify the main clinical pros and cons regarding current use of BDZs in clinical practice, and provide an updated overview of their use across specific clinical areas and patient populations. The main results are presented and discussed in this review.