By Harry Shapiro
The brain has a whole fleet of chemical couriers called neurotransmitters (NTs) which it uses to send messages to different parts of the body. They are released across a synaptic gap to engage with receptors on the other side as a key fits a lock. The brain then reabsorbs the chemical waiting for the next event to occur that will stimulate release. About 100 NTs have so far been identified: one of these is serotonin. It has a number of functions, but one is to regulate mood and increase good feelings.
The theory behind antidepressants is that depression is caused by a lack of serotonin in the brain and the way to deal with that is to prevent the brain from reabsorbing serotonin, leaving it sloshing around to elevate mood. But according to Robert Whitaker, a Pulitzer short-listed science writer speaking at a packed meeting of the All Party Parliamentary Group on Prescribed Drug Dependence on 11th May, this is all wrong. So wrong in fact, that taking these drugs over the long term, makes the depression worse.
This meeting was called to highlight the fact that in several countries across the world with very different health care systems, there is a close correlation between increasing levels of antidepressant prescribing and claims for mental health disability payments. For example, 61m prescriptions for antidepressants were issued in England alone in 2015 – four times as many as in 1995 – while there were over 1.1m disability claims for mental health disorders in the UK in 2014, over double the number 20 years ago.
To get some more insights into his (for me anyway) startling presentation, I spoke to Robert Whitaker after the meeting. Antidepressants such as Prozac are known as Serotonin Specific Reuptake Inhibitors or SSRIs, in other words they block the reabsorption of serotonin into the brain. And in the early stages of drug treatment, they do just that. So it would be wrong to say that these drugs don’t work. But according to Whitaker, after an (undetermined) while, the brain takes what might be called evasive action against the SSRI and reduces the amount of serotonin it releases for the SSRI to then block. So in theory, as the patient takes more and more drug, there is less and less of the happy chemical being released in the first place and so the person feels worse.
Whitaker also offered an explanation as to why people can feel so bad, long after they have stopped taking the drug. When somebody withdraws from heroin, they feel awful for a few weeks while the body’s natural opiates called endorphins fill the gaps left by heroin. But apparently, it takes the brain far longer to readjust levels of serotonin and, according to Whitaker, some research evidence suggests this state might be permanent. Which of course, doesn’t mean that ‘once depressed, always depressed’ – there will be any number of variables that differ from person to person concerning long term prognosis, but it would account for the symptoms people experience after they have stopped treatment which are not (as some doctors would argue) simply a case of the old feelings which caused the depression flooding back.
I assumed that this problem with antidepressants was entirely the product of new research. Not so. According to Robert Whitaker (and reminiscent of tobacco company secret knowledge about the link between smoking and cancer), Big Pharma had some of the key data to hand back in the 1970s.