Psychiatrists have been aware for years that low serotonin levels may not cause depression, despite continuing to prescribe the pills, a chair of psychology has said.
Dr Jonathan Raskin, who is also a psychotherapist at State University of New York, told DailyMail.com he’d been concerned that the theory that depression was caused by low serotonin levels was ‘incomplete’ for ‘a while’.
But he said many medics continued to prescribe the medication, even while they were unsure if they were effective, because it was ‘easier’ than offering more time-intensive care.
The pills could still help some patients, he added, but they are not a ‘cure-all’ for those suffering from depression.
This week a landmark UK study called into question society’s ever-growing reliance on antidepressants like Prozac.
The $15billion-a-year industry — set to grow to $21billion in the next decade — sees patients prescribed pills like Prozac on the promise they will cure people’s depression by raising levels of serotonin, a neurotransmitter in the brain.
But after reviewing 17 major studies scientists at University College London said they found no convincing evidence that a lack of this chemical sparked the condition.
Dr Jonathan Raskin, chair of psychology at State University of New York at New Paltz, said many experts had been concerned the theory was ‘incomplete’
Researchers from University College London said a review of evidence has found no link between low serotonin levels and depression casting doubt on antidepressants designed to boost levels of the ‘feel good’ chemical. But other experts have cast doubt of the findings
About 13 percent of American adults take antidepressants every year, figures show.
But rates are much higher among women, with up to 18 percent prescribed the medications annually.
Asked whether low serotonin levels caused depression, Raskin said: ‘I think most mental health professionals familiar with the research have known for a while that the serotonin theory of depression is incomplete and has mixed research support.
‘Depression is a complicated issue, and the idea we would be able to reduce it simply to serotonin is not right.
‘When we give antidepressants, we don’t do this based on biological tests showing they don’t have enough serotonin — but if we think it could help them.’
Asked whether people should keep taking the pills, he said: ‘I think that this is a conversation worth having.
‘I am not going to say people should or should not be on them, but I think there has been a lot of popular dissemination of the idea that we have reduced depression to low serotonin levels.
‘Antidepressants have some effect some of the time for some people, but I don’t think they are a cure-all.’
WHAT IS DEPRESSION? SYMPTOMS AND CAUSES
While it is normal to feel down from time to time, people with depression may feel persistently unhappy for weeks or months on end.
Depression can affect anyone at any age and is fairly common – approximately one in ten people are likely to experience it at some point in their life.
Depression is a genuine health condition which people cannot just ignore or ‘snap out of it’.
Symptoms and effects vary, but can include constantly feeling upset or hopeless, or losing interest in things you used to enjoy.
It can also cause physical symptoms such as problems sleeping, tiredness, having a low appetite or sex drive, and even feeling physical pain.
In extreme cases it can lead to suicidal thoughts.
Traumatic events can trigger it, and people with a family history may be more at risk.
It is important to see a doctor if you think you or someone you know has depression, as it can be managed with lifestyle changes, therapy or medication.
Source: NHS Choices
He added: ‘They are easier to prescribe and give to people than provide more time intensive things like psychotherapy.
‘So they may be offered to people despite other solutions being equally or more effective.’
One academic involved in the UK study described the findings as ‘eye-opening’, and that ‘everything I thought I knew has been flipped upside down’.
Lead author Professor Joanna Moncrieff, a psychiatrist, said: ‘The popularity of the “chemical imbalance” theory has coincided with a huge increase in the use of antidepressants.
‘Thousands suffer from side effects of antidepressants, including severe withdrawal effects that can occur when people try to stop them, yet prescription rates continue to rise.
Serotonin helps carry signals in the brain and is thought to have a positive influence on mood, emotion and sleep.
They are preferred to other types of antidepressants because they cause fewer side effects. Yet they can still lead patients taking them to experience anxiety, diarrhea, dizziness and blurred vision.
Depressed patients can also be hit by crippling withdrawal symptoms when they try to come off the pills.
At the same time, a raft of studies have suggested they don’t work any better than a placebo.
The UCL study, published in the journal Molecular Psychiatry, analyzed 17 previous reviews dating back to 2010 and consisting of dozens of individual trials.
It does not prove SSRIs don’t work. However, it does suggest the drugs don’t treat depression by fixing abnormally low serotonin levels.
SSRIs have no other proven way of working, Professor Moncrieff and colleagues said.
She added: ‘We can safely say that after a vast amount of research conducted over several decades, there is no convincing evidence depression is caused by serotonin abnormalities, particularly by lower levels or reduced activity of serotonin.
‘We do not understand what antidepressants are doing to the brain exactly.
‘Giving people this sort of misinformation prevents them from making an informed decision about whether to take antidepressants or not.’
Studies used in the review involved hundreds of thousands of people from various countries.
They found there was no difference in serotonin levels between people diagnosed with depression and healthy people, despite polls suggesting up to 95 per cent of the public believing this is the case.
Artificially lowering serotonin levels in healthy volunteers also did not lead them to developing depression.