OK – I’ll come clean.
“A simple enough question” (28 Dec 2006) was a trick question – no one really knows what a ‘correct’ level of serotonin is – it is merely a marketing concept. You don’t have to take my word for it, though. I’ll let Professor David Healy explain.
What makes Healy of particular interest is that he’s no maverick, driven by a belief in herbs or the healing power of madness. He is a mainstream biological psychiatrist and director of the North Wales Department of Psychological Medicine in Bangor, he has written a highly acclaimed history of anti-depressants, The Anti-depressant Era, as well as Let Them Eat Prozac – and he is the author of more than 100 scientific papers. But he is concerned that patients and the profession are not being told the truth about the risks.
Nineteen years ago, depression was viewed as a severe mental condition that often required hospitalisation, while anxiety, sadness, worries about social situations and feeling tired all the time were considered milder conditions and treated with tranquillisers such as Valium. With the arrival of SSRIs, tranquillisers fell heavily out of favour because they had been shown to be addictive. In their place were SSRIs – safe, non-addictive and effective. The one psychopharmacological fact everyone became familiar with (thanks to the marketing departments of Big Pharma) was that serotonin is the brain’s feel-good chemical: too little of it and you feel blue, worried, down, depressed. SSRIs increase the amount of serotonin available in the brain.
“The only problem with this story,” Healy told an audience at the Institute of Psychiatry in London in February 2002, “is that there are no studies proving that serotonin levels have anything to do with depression.” He can speak with some authority on this because, before moving to Bangor, he was researching serotonin receptors at the Department of Psychiatry at Addenbrooke’s, Cambridge. “SSRIs can certainly have an effect on mood, and for some people they are very effective. But we don’t really understand how they work, and it is not by directly changing serotonin levels.”
When SSRIs were launched, they were described as anti- depressants to distinguish them from the addictive tranquillisers. But there was a marketing problem. They weren’t actually effective in treating classic depression. What was needed was for them to become the drug of choice for the people previously given tranquillisers. The key to this was the notion that low levels of serotonin were a problem that could be treated as a deficiency disorder, on a par with having low levels of a vitamin or mineral. That old-fashioned benzodiazepines, such as Valium, had dealt with these anxiety disorders by affecting an entirely different brain chemical, known as gamma-aminobutyric acid (GABA), was simply ignored.
I’ll finish with another quote from Professor Healy: “The serotonin theory of depression is comparable to the masturbatory theory of insanity. Both have been depletion theories, both have survived in spite of the evidence, both contain an implicit message as to what people ought to do. In the case of these myths, the key question is whose interests are being served by a widespread promulgation of such views rather than how do we test this theory.”