A single antidepressant tablet makes a
depressed person see the world in a more positive light just four
hours after swallowing it, a new study has shown.
Dr Philip Cowen, professor of pharmacology at
the Department of Psychiatry at the University of Oxford, told
delegates at the Royal College of Psychiatrists’ Annual Meeting in
London that antidepressant medication starts to work far faster
than most clinicians assume.
“Depressed people interpret the world in a
negative way,” he said. “They become stuck in this state.
Negativity causes depression and depression causes negativity and,
whatever happens, events will be interpreted in a negative
way.”
Antidepressants elevate mood, which in turn
leads to a depressed person becoming more positive and interpreting
things that happen to them in a positive way. Prof Cowen said:
“Antidepressants change biases. People who take them begin to see
the world in a positive light,” said Prof Cowen
But it does not take weeks for this change to
happen. Prof Cowen and his colleagues gave 30 depressed people one
single 4mg dose of reboxetine – which inhibits the update of both
serotonin and noradrenaline in the brain – and compared them with
30 ‘controls’ who were given a placebo or dummy pill.
The researchers asked both groups to carry out
a series of simple tasks, including picking out the ‘happy’ facial
expression from a line of faces, and recalling positive rather than
negative words. They found that the placebo group were poor at
spotting happy faces. They also tended to remember the negative
words and were slow to categorise positive information.
However, four hours after taking a single dose
of reboxetine, the drug group were as capable of remembering the
positive words and spotting the happy expression as people who were
not depressed.
Prof Cowen said: “People with depression
interpret their internal and external worlds in a negative way. The
current antidepressant drugs take away the automatic feelings of
negativity at the first dose.”
Antidepressants affect mood indirectly by
abolishing the negative bias in the way that depressed people
appraise personal and social experience at a subconscious
level.
While there might be little change in overall
conscious mood, Prof Cowen concluded: “Over time, and with a fair
wind, this can lead to feeling better and improve the changes of
recovery.”
For further information, please contact Liz Fox or Deborah
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Telephone: 020 7235 2351 Extensions. 6298 or 6127
References:
The Annual Meeting of the Royal College of Psychiatrists, Imperial College, London, 1 – 4 July 2008