Downloaded from jme bmjjournals com on 2 October 2006 Psychopharmacology and memory W Glannon J Med Ethics 2006 32 74 78 doi 10 1136 jme 2005 012575 Updated information and services can be found at http jme bmjjournals com cgi content full 32 2 74 These include References Rapid responses Email alerting service Topic collections This article cites 12 articles 4 of which can be accessed free at http jme bmjjournals com cgi content full 32 2 74 BIBL You can respond to this article at http jme bmjjournals com cgi eletter submit 32 2 74 Receive free email alerts when new articles cite this article sign up in the box at the top right corner of the article Articles on similar topics can be found in the following collections Other Ethics 1402 articles Notes To order reprints of this article go to http www bmjjournals com cgi reprintform To subscribe to Journal of Medical Ethics go to http www bmjjournals com subscriptions Downloaded from jme bmjjournals com on 2 October 2006 74 NEUROETHICS Psychopharmacology and memory W Glannon J Med Ethics 2006 32 74 78 doi 10 1136 jme 2005 012575 Psychotropic and other drugs can alter brain mechanisms regulating the formation storage and retrieval of different types of memory These include off label uses of existing drugs and new drugs designed specifically to target the neural bases of memory This paper discusses the use of beta adrenergic antagonists to prevent or erase nonconscious pathological emotional memories in the amygdala It also discusses the use of novel psychopharmacological agents to enhance long term semantic and short term working memory by altering storage and retrieval mechanisms in the hippocampus and prefrontal cortex Although intervention in the brain to alter memory as therapy or enhancement holds considerable promise the long term effects of experimental drugs on the brain and memory are not known More studies are needed to adequately assess the potential benefits and risks of these interventions M Correspondence to Walter Glannon Department of Philosophy University of Calgary Calgary Alberta T2N 1N4 Canada glannon ucalgary ca Received 20 April 2005 In revised form 6 July 2005 Accepted for publication 8 July 2005 www jmedethics com emory is critical to both human survival and personal identity Non conscious emotional memory of fearful or threatening events enables us to recognise and respond appropriately to real threats in the natural and social environment Episodic memory of events involving personal experience is necessary for the psychological connectedness and continuity that gives one the feeling of persisting through time as the same person Other forms of memory include non conscious procedural memory which enables us to perform basic motor skills and tasks of daily life and semantic memory which enables us to recall and use concepts and facts Semantic and episodic memory are two forms of declarative memory which enables us to consciously recall facts and events Working memory is a short term version of declarative memory and is involved in such complex cognitive tasks as reasoning and decision making Recent advances in psychopharmacology are enabling researchers to intervene in emotional semantic and working memory systems In the first type of intervention existing drugs are being used to block or reverse the process through which non conscious fearful memories of traumatic events become pathological and cause post traumatic stress disorder PTSD and similar debilitating mental illnesses It is because they are used to treat mental disorders that these drugs are a form of therapy In the second type of intervention drugs are being designed to enhance the formation storage and retrieval capacity of long term semantic and short term working memory It is because they are used to strengthen a capacity considered normal that these drugs are a form of enhancement These interventions hold considerable promise but they may also involve pitfalls Both classes of drugs are experimental in the sense that they are being developed and used for off label purposes for which they were not originally designed Because they are experimental the long term effects of these novel forms of psychopharmacology are unknown I will discuss some of the potential beneficial and harmful effects of psychopharmacology on memory THERAPEUTIC PSYCHOPHARMACOLOGY Adrenaline is a hormone released by the adrenal medulla in situations requiring effort to fight against or flee from a perceived or real threat It is closely related to the other stress hormone cortisol Adrenaline is released when the adrenal gland receives a signal from the amygdala in the brain when this structure senses an external threat to a human organism The amygdala is part of the brain s limbic system which regulates emotions 1 2 It is one of the most primitive parts of the brain and plays a critical role in our capacity to avoid threats and survive One effect of adrenaline is to embed non conscious emotional memories of fearful or threatening events in the amygdala If emotional memory is embedded too strongly in the amygdala however it can produce a heightened fear response to external events that is out of proportion to the actual nature of the problems at hand Because emotional memories stored in the amygdala are out of our conscious control they can be difficult to eradicate or modulate and can adversely influence the nature and content of our beliefs feelings and other conscious mental states Events perceived as stressors or threats can trigger a chronic fear response that puts the brain body and mind on a constant state of alert This describes the pathology and pathophysiology of some forms of depression anxiety and the emotionally disturbing flashback memories of traumatic events that characterise PTSD Some researchers have raised the possibility of using a beta adrenergic antagonist specifically the drug propranolol to treat PTSD This drug blocks the effects of the hormone norepinephrine levels of which rise in the brain in response to adrenaline The aim of using propranolol would be to prevent the embedding of pathological unconscious emotional memories of fearful events in the amygdala Brian Strange and Abbreviations CREB cyclic AMP response element binding protein PTSD post traumatic stress disorder Downloaded from jme bmjjournals com on 2 October 2006 Psychopharmacology and memory colleagues have conducted experiments the results of which appear to support this hypothesis 3 The