- It is known as one of the “happy hormones” and its discovery ultimately led to the development of what were hailed as depression ‘wonder drugs’ like Prozac.
- But, despite being prescribed as a treatment for anxiety, these ‘SSRI’ drugs designed to boost levels of serotonin in the brain had a strange and mysterious side-effect. In some cases, they initially made people feel more anxious or even suicidal.
- Now a new study, published in the journal Nature, has found that, contrary to the popular view serotonin only promotes good feelings, it also has a darker side.
- Researchers in the US delivered a mild shock to the paws of mice and found this activated neurons that produce serotonin in an area of the brain known to be involved in mood and depression.
- Artificially increasing these neurons’ activity also appeared to make the mice anxious.
- Using sophisticate equipment to monitor the mice’s brains, the scientists, from North Carolina University’s medical school, then mapped what they described as an “essential” serotonin-driven circuit “governing fear and anxiety”.
- Professor Thomas Kash, one of the researchers, said: “The hope is that we’ll be able to identify a drug that inhibits this circuit and that people could take for just the first few weeks of SSRI use to get over that hump.
- “More generally, this finding gives us a deeper understanding of the brain networks that drive anxiety and fear behaviour in mammals.”
- According to the NHS website, SSRIs are “usually the first choice medication for depression” because they “generally have fewer side effects”.
- “These can be troublesome at first, but they’ll generally improve with time,” it says.
- It says the “common side effects” of the drugs can include: “Feeling agitated, shaky or anxious; feeling or being sick; dizziness; blurred vision; low sex drive; difficulty achieving orgasm during sex or masturbation; in men, difficulty obtaining or maintaining an erection.”
- The US researchers said the next step was to find out whether the same serotonin brain circuitry exists in humans.
Source: The Independent
