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| Psychedelic drugs return as potential treatments for mental illness New research confirms that psychedelic drugs are promising treatments for depression, obsessive-compulsive disorder (OCD) and schizophreniaMoheb Costandi writes the Neurophilosophy blogLong before hippie poster boy Timothy Leary invited the world to "Turn on, tune in and drop out", a group of pioneering psychiatrists working in Canada began to treat alcoholics with lysergic acid diethylamide (LSD), and reported unprecedented recovery rates. Far from being at the fringes of medical research, their work was fully supported and funded by the Canadian government, and became a promising new area of research that played a role in modernising the field of psychiatry. But despite the encouraging results, studies of LSD therapy ended abruptly in the late 1960s, and did not resume again until some 40 years later. At the cutting edge of early psychedelic research was one Humphry Osmond (1917-2004), a British psychiatrist at the Weyburn Mental Hospital in the Canadian province of Saskatchewan. It was Osmond who gave the novelist Aldous Huxley his first dose of mescaline in 1953, and coined the term "psychedelic" in 1957. Between the years of 1954 and 1960, Osmond and his colleague Abram Hoffer treated some 2,000 chronic alcoholics with LSD. None of these patients had responded to other treatments, and yet, Osmond and Hoffer reported that up to 45% of those treated with a single large dose of the drug abstained from drinking for at least a year afterwards. Other researchers in Canada, Britain, the United States and elsewhere began experimenting with LSD therapy, and by the time the drug hit the streets in the early 1960s, there were more than a thousand published research papers that described promising results in over 40,000 patients. These studies took place alongside trials of newly developed compounds such as the antipsychotic chlorpromazine and the tricyclic antidepressant imipramine. This body of work effectively established the new field of psychopharmacology, which led psychiatrists to abandon the psychoanalytical approach they had been using since the turn of the century, and begin to consider alcoholism and mental illnesses in terms of disrupted brain chemistry.Although the results of many of the early studies into LSD therapy were promising, investigations of the potential therapeutic benefits of the psychedelic drugs stopped towards the end of the decade, for two main reasons.First, some began to question the methods used in the studies, arguing that they lacked scientific rigour, and few, if any, other researchers managed to replicate the high recovery rates reported by Osmond and Hoffer. Many therefore viewed the early studies as providing nothing more than anecdotal evidence for the therapeutic benefits of LSD.Second, and more importantly, the cultural and political climate became less conducive to psychedelic research. LSD became a popular recreational drug towards the end of the 1960s, and came to be associated with the hippie counterculture, anti-authoritarianism and social disobedience. As a result, research funding quickly dried up, and the drug was eventually criminalised by the US and other governments in 1970. The past decade has seen renewed interest in the potential therapeutic benefits of LSD and other psychedelic drugs, and the availability of sophisticated techniques such as functional neuroimaging is beginning to provide fresh insights into how they affect the brain. The new research confirms that the psychedelic drugs do indeed have therapeutic value for a number of psychiatric conditions, including depression, obsessive-compulsive disorder (OCD) and schizophrenia. It also points to various brain mechanisms which may underly their beneficial effects. We now know that the so-called classical hallucinogens (LSD, psilocybin and mescaline) activate 5-HT2A receptors – which normally bind the neurotransmitter serotonin – in the deep layers of the prefrontal cortex. This in turn alters nerve cell signalling mediated by the transmitters glutamate and dopamine, and may also lead to changes in the strength of connections between neurons in the cortex and other parts of the brain.Serotonin and dopamine convey messages in the brain circuits involved in mood, and psychedelic drugs apparently alleviate the clinical symptoms of mood disorders by modulating the activity of the cells in these circuits and by modifying their connections.The very latest research shows that ketamine, an anaesthetic with hallucinogenic properties, can reduce the symptoms of depression quickly and effectively, and that MDMA (popularly known as ecstasy) can be beneficial to sufferers of post-traumatic stress disorder when used in combination with behavioural therapy.By contrast, new research into the effects of the classical hallucinogens has progressed at a much slower pace, probably because these drugs are categorised as Class A in the UK (Schedule I in the US), and researchers who wish to obtain them therefore face numerous regulatory barriers.Nevertheless, it now seems quite clear that psychedelic drugs have enormous potential for treating a wide variety of psychiatric conditions. Much still remains to be discovered about exactly how they affect the brain, however. For example, optimising their clinical benefits will require a better understanding of how their molecular structures are related to their activity, and of how each drug can be combined with psychotherapeutic approaches to achieve the best results. Furthermore, because most psychedelics can mimic the symptoms of naturally occurring psychoses – they can, for example, induce hallucinations and disorganised thought processes – future research may reveal some of the brain mechanisms underlying schizophrenia and related conditions.The debate that occurred in the 1960s about the therapeutic use of LSD mirrors the one taking place today over the use of MDMA, so the history of LSD experimentation could provide valuable lessons about how to incorporate these controversial drugs into modern medicine.Moheb Costandi is a molecular and developmental neurobiologist who writes the Neurophilosophy blogFurther readingThe secret history of psychedelic research (Neurophilosophy)Serotonin, psychedelics and depression (The Neuroskeptic)Ketamine for depression: yay or neigh? (The Neurocritic)Visions of a psychedelic future (Mind Hacks)Vollenweider, F. X. & Kometer, M. (2010). The neurobiology of psychedelic drugs: implications for the treatment of mood disorders. Nature Reviews Neuroscience; 11: 642-651.• Moheb Costandi writes the Neurophilosophy blogDrugsPsychologyMedical researchBiochemistry and molecular biologyChemistryDrugsHealthDepression in adultsguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Why do we eat chilli? Chillies burn our tongues, make our eyes water and bring us out in a sweat. Jason Goldman looks at a peculiarly human form of masochismJason is a developmental psychologist and blogs at The Thoughtful AnimalDave's Red Hot. Mother Puckers. Green Bandit. Scorned Woman. Pain is Good. Blair's Death. No, they're not rock bands. These names represent just a small selection of the brands of hot sauce available at my local supermarket.Humans, apparently, enjoy torturing themselves. Spiciness, after all, is not a flavour, not like sweet or salty or sour. Spicy means pain. The sensation of spiciness is the result of the activation of pain receptors in the tongue. According to psychologist Paul Rozin of the University of Pennsylvania, about a third of the people around the world eat hot peppers every single day. Why? Because they "love the burn". At a symposium on gastro-psychology during this year's Association for Psychological Science convention, Rozin pointed out that humans are the only species – we know about – that specifically seek out what would otherwise be considered negative events.Healthy, sane humans do not stab themselves in the thighs, or bathe their eyes in lemon juice. So why do we so love to assault one of the most sensitive organs in the human body, the tongue, with what amounts to chemical warfare? Chillies are unique among foods that we should otherwise not enjoy. For example, humans also have natural aversions to the bitterness of coffee or the harshness of tobacco, but those substances have some addictive qualities, which might make them desirable. Capsaicin, the compound that provides the mouth-watering punch of chillies, does not seem to have any addictive qualities whatsoever. And yet the preference for capsaicin is almost universal; nearly every culture has incorporated it into their cuisine in some way, for milllennia.Rozin writes:"There are records suggesting use of chilli pepper dating back to 7000BC in Mesoamerica; they were domesticated some thousands of years after this. These fiery foods made their debut in the Old World when they were brought back by Columbus and other early explorers. In spite of their initial unpalatability, they became accepted as a basic part of the diet in many parts of the world: west and east Africa, India, south-east Asia, parts of China, Indonesia, Korea, and other smaller geographic regions, such as Hungary."Most young children, even from cultures known for their spicy recipes, are averse to capsaicin. So maybe, then, instead of actually liking the pain, we're merely desensitising ourselves: what used to be really painful is now just sort of painful.Since capsaicin is a member of the vanilloid family of molecules, it binds to a receptor on the tongue called the vanilloid receptor subtype 1. Upon binding to the VR1 receptor, the sensation produced by the capsaicin molecule is the same sensation that heat would cause, which explains capsaicin's burn. When scientists discovered that the VR1 receptor was a member of the larger family of TRP ion channels, the VR1 receptor was renamed TRPV1. TRP receptors are known to be sensitive to changes in temperature and are likely responsible for temperature sensation. When chilli peppers are the source of the capsaicin, there isn't any actual tissue damage; but because it binds to the TRPV1 receptor, the brain is tricked into believing that the tongue truly is on fire.In 1980, Rozin and a colleague, Deborah Schiller, reported a study in which they compared the pepper preferences of Mexicans and Americans. Mexicans generally eat chillies several times per day, while Americans only eat chillies a few times a week. If desensitisation could explain our preference for oral pain, then Mexicans should show higher tolerance for capsaicin than Americans, and Americans should more easily detect capsaicin, even in small amounts, than Mexicans.The data only weakly supported these predictions: the differences were seen, but were not statistically significant. Another prediction made by the desensitisation hypothesis is that individual tolerance should increase with exposure, and therefore with age. Rozin and Schiller found no correlation between age and tolerance though. Experiments conducted to try to induce a preference for capsaicin in rats, using traditional reinforcement techniques, proved futile.In the late 1970s, Frito-Lay tried to market a brand of corn chips in Mexico that had the flavour of chilli peppers, but without any capsaicin. As would be expected in a culture that actually enjoys the burn, the product was a failure. Likewise, bell peppers, which have some pepper flavour but no capsaicin, are not at all popular in Mexico.While most scientists still do not quite have a handle on the human preference for spicy foods, the best explanation comes from a mechanism called "hedonic reversal", or "benign masochism". Something happens, in millions of humans each year, which changes a negative evaluation into a positive evaluation, like flipping a light switch.Rozin writes: "If the oral receptors are sending the same message to the brain in the chilli liker and the chilli hater, then the chilli liker must have come to like the very same sensation that the chilli hater, the infant, and nonhuman animals find aversive. One gets to like the burn." Only humans seem to be able to derive pleasure from the negative sensation itself. Animals have been trained to endure self-harm, but only within the context of positive reinforcement.Perhaps we seek out the painful experience of snacking on chillies while consciously maintaining awareness that there is no real danger to ourselves. After all, people seem to enjoy – and actively seek out – many other sensations that are otherwise undesirable but are ostensibly safe: the sensation of falling provided by rollercoasters or skydiving, the feelings of fear and anxiety while watching horror movies, the physical pain experienced upon jumping into icy water, or even the feelings of sadness that come while watching a tear-jerker. Perhaps it is this cognitive mismatch itself that provides the thrill: like strapping into a rollercoaster or popping Hostel into your DVD player over and over again, the burn of capsaicin only seems to be threatening.Want a thrill? Go out and buy yourself a bottle of One Fuckin' Drop At A Time Hot Sauce. It comes with an eye-dropper for portion control. Benign masochism, indeed.Jason Goldman is a developmental psychologist and blogs at The Thoughtful AnimalFood sciencePsychologyFood & drinkNeuroscienceguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
GM salmon Is genetically modified fish swimming against the tide? bbc.co.uk |
Video: Scientists protest against funding cuts on Science is Vital rally Scientists and their supporters demonstrate against threatened cuts to science funding outside the Treasury in London on SaturdayAlok Jha guardian.co.uk |
Last year's moonshot splashed up lots of water By ALICIA CHANG 2010-10-22T01:22:14ZLOS ANGELES (AP) -- When NASA blasted a hole in the moon last year in search of water, scientists figured there would be a splash. They just didn't know how big. Now new results from the Hollywood-esque moonshot reveal lots of water in a crater where the sun never shines - 41 gallons of ice and vapor.... hosted.ap.org |