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Trial showed healthy people given a
Parkinson’s drug became more selfish, while people given a serotonin-boosting
drug were more protective of others
Common drugs for depression and
Parkinson’s can sway people’s moral judgments about harming others, according
to research that raises ethical questions about the use of the drugs.
The study found that when healthy
people were given a one-off dose of a serotonin-boosting drug widely used to
treat depression they became more protective of others, paying almost twice as
much to prevent them receiving an electric shock in a laboratory experiment.
They also became more reluctant to expose themselves to pain.
Serotonin map of brain could lead
to better targeted antidepressants
The scientists also found that the
dopamine-enhancing Parkinson’s drug, levodopa, made healthy people more
selfish, wiping out the normal tendency to prefer to receive an electric shock
themselves, while sparing those around them.
Molly Crockett, a psychologist at
the University of Oxford who led the work, said the finding that a single
exposure to the drugs had such a noticeable impact on behaviour challenged the
idea that we have stable moral values.
“Patients [taking these drugs] are
tracked in terms of how their symptoms improve, but not necessarily in terms of
how their behaviour changes,” she said. “In the treatment of Parkinson’s, some
patients go on to develop compulsive gambling and compulsive sexual behaviour.
The drugs have consequences that reach out into the world beyond the patient.”
She added that it was unclear
whether the effects seen in the study would be replicated in patients. An
alternative possibility is that the drugs could bring the behaviour of patients
“back to baseline” by stabilising their psychological state.
“The central message is we need to
have more research into how these drugs affect behaviour, both in healthy
people and in people taking them for disorders,” she said.
In the study, published in the journal Current Biology,
175 participants took part, with 89 assigned to receive the anti-depressant
citalopram or a placebo and 86 given either levodopa or a placebo.
The participants were also randomly
designated as “deciders” or “receivers” and anonymously paired up. All
participants were given mildly painful electric shocks matched to their pain
threshold so that the intensity was not intolerable. Deciders were told that
shocks to receivers would be at the receiver’s own pain threshold.
People given levodopa, however,
were not willing to pay any more to prevent shocks to others than to prevent
shocks to themselves. On average, they were prepared to pay approximately 35p
per shock to prevent harm to themselves or others, meaning they delivered on
average 10 more shocks to others during the experiment than the placebo group.
“The dopamine drug made people more
selfish,” said Crockett. “Most people show this pattern where they think it’s
worse to harm other people than to harm oneself. That’s abolished by the drug.”
The researchers suggest that in future
it may be possible to give people a simple test to assess whether their
decision-making behaviour has been radically altered by a drug, as well as
asking them about whether their mood and symptoms have improved.
“We’re not transforming someone
from a healthy person into a criminal or anything like that,” Crockett said.
“But in aggregate we make decisions multiple times a day and they can shape our
lives.”
http://www.theguardian.com/science/2015/jul/02/parkinsons-and-depression-drugs-can-alter-moral-judgement-study-shows?
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Serotonin map of brain could lead to
better targeted antidepressants
Researchers hope to discover how the
activity of serotonin in the brain is involved in different mental illnesses
By understanding the biology of
serotonin, drugs could be developed that only target cells relevant to a
particular mental disorder – reducing side-effects. Photograph: Mark
Thomas/Alamy
Research that aims to map the
activity of serotonin in the brain could revolutionise the use of
antidepressants and behavioural therapy for people with mental illnesses.
The neurotransmitter serotonin has
long been associated with mood, with drugs that boost the chemical in the brain
helping to alleviate the symptoms of common illnesses such as depression and
anxiety, but scientists lack a deep understanding of how it mediates different
mood disorders.
By understanding the biology of
serotonin, the hope is that drugs can be created that only target cells
relevant to a particular disorder and behavioural therapies can be made more
effective, reducing the need for antidepressants.
Dr Jeremiah Cohen, an assistant
professor at the Johns Hopkins
Brain Science Institute in Baltimore, said: “The ultimate aim is to
understand the biology of mood and how groups of cells in the brain connect to
produce our emotional behaviour. Most antidepressants operate broadly in the
entire serotonin system. What we hope to do with this map is use drugs that are
available or design new drugs that will target only the components of that
system relevant to a particular disorder.”
The use of antidepressants in England
has soared since the late 1990s, raising concerns in some quarters about
over-prescription. Researchers from
the Nuffield Trust and the Health Foundation found that 40m prescriptions for
antidepressants were made in 2012, compared to 15m in 1998. Doctors
write prescriptions for more than one in 10 adults in developed countries, with
Iceland, Australia, Canada and European Nordic countries leading the way, according to
2013 data from the Organisation for Economic Co-operation and Development.
More than 10% of American adults have used antidepressants.
Antidepressants that are better
targeted could also avoid some of their common side-effects such as insomnia
and sexual dysfunction, because the drugs could be designed to only affect the
part of the brain involved in mood, said Cohen.
He is one of four researchers chosen
by the charity MQ: Transforming Mental Health
to share £900,000 to
carry out mental health research. The effectiveness of selective
serotonin reuptake inhibitors (SSRIs) as antidepressants strongly suggests that
serotonin transmitter pathways are involved in illnesses such as depression and
anxiety but little is known about the biology of the chemical. “Almost by
accident scientists discovered that drugs that work on serotonin can affect
mood,” said Cohen. “We are working with a blunt system and we need to refine
it.”
He will build on preliminary studies
of serotonin neurons in mice while the animals perform “reward and punishment”
tasks. By monitoring their behaviour during the tasks, he and his colleagues
will be able to map how the neurons participate in well-known responses that
are analogous to human behaviours. He said that scientists have long been
interested in mapping mood in the brain by dissecting the behaviour of
serotonin neurons but in the past they have not had the technology to do it.
“In neuroscience we are where physics was with Galileo and Newton,” he said.
“It’s basic stuff. An observer might say we should know that [already], it
seems like such an obvious thing we want to understand.”
MQ chief executive Cynthia Joyce
said: “Whether medication or psychological therapy, it is vital that people
receive the most effective mental healthcare that works for them. Dr Cohen’s
research addresses a long-standing gap in our understanding of mental illness.
Excitingly, it has the potential to help us to achieve better, more
personalised treatments for millions of people.”
http://www.theguardian.com/science/2015/jan/05/serotonin-map-brain-antidepressants-mental-illnesses
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