He had a change of heart, literally. American Sonny Graham underwent a heart transplant in 1995 and started exhibiting traits of his deceased donor soon after, before committing suicide in the same manner early this month.

In another case, a dancer from Massachusetts in the United States, Ms Claire Sylvia, then 47, received the heart and lungs of an 18-year-old accident victim in 1988.

She then went on to pen an autobiography, telling a baffling tale of how her tastes had changed to those of a teenager's since the operation.

Do these examples prove that organ recipients take on the personality traits of their donors?

While it has been reported that scientists have documented over 70 such cases to date, doctors in Singapore say it is not scientifically possible.

East Shore Hospital consultant cardiologist Baldev Singh says: 'The heart is a mechanical organ, it has no thinking ability. There are no brain cells or neurons which can process knowledge and store memory, so I see no scientific explanation for this phenomenon.'

His opinion is that it is a psychological manifestation of the recipient's feeling of closeness to the donor - the donated organ most probably saved his life - leading to a need to fit into the donor's shoes to identify himself with the donor.

Dr Bernard Kwok, senior consultant cardiologist with the National Heart Centre and consultant cardiologist with the Mt Elizabeth Medical Centre, is also sceptical.

He says there have been no documented cases in Singapore. In fact, he points the finger at tabloids in other countries such as the United States which sensationalise stories such as 'how a woman became an alcoholic because she received a trucker's heart'.

While he accepts that personality changes can occur in the early stages after an organ transplant, they can usually be explained: the psychological adjustment from living with a death sentence to a new lease on life; and high doses of steroids which are administered to transplant patients after the operation to prevent rejection of the organ, which can have psychological effects.

'Each transplanted organ has its own DNA, but it's in the organ, not the brain. It's too far-fetched to explain a change in behaviour,' he adds.

Psychiatrists LifeStyle spoke to say this kind of behaviour is very rare and is almost always linked to the psychological stress the patients suffer.

Hence, in Singapore, it is mandatory for patients to be assessed by psychiatrists before undergoing an organ transplant.

And, according to Dr Brian Yeo, consultant psychiatrist at Mount Elizabeth Medical Centre, many of these patients suffer from social and emotional conflicts.

He agrees that steroids are a factor in a change in the patient's personality.

Dr Calvin Fones, consultant psychiatrist at Gleneagles Medical Centre, says: 'The recipient being related to the donor or having pre-existing psychological issues may account for this type of behaviour.'

However, he states that it is a very rare occurrence, and there are many more plausible explanations than a person having absorbed personality traits from his donor.

Dr Adrian Wang, consultant psychiatrist at Gleneagles Medical Centre, attributes it to the psychological stress that patients suffer.

'They feel a sense of gratitude towards the donor, and start to see similarities between themselves and the dead person, possibly because of guilt, though these people probably have pre-existing issues,' he says.

As for how this can be treated, he says there is no standard treatment as there have been no documented cases in Singapore.

Pushed for a professional reaction to a hypothetical case, he says: 'If the person is happy adopting the donor's persona, no action is necessary. Only if they start creating problems for themselves and their families will we step in and counsel them to find the underlying root of the problem.'

tiffanyt@sph.com.sg

This story was first published in thesundaytimes on Apr 20, 2008.