Thaindian News

London, April 15 (IANS) A brain chemical called serotonin is likely to influence why we may consider a couple to be intimate and romantic or jaded and bored.

For instance, adult volunteers, whose levels of serotonin activity had been lowered, rated couples in photos as being less intimate and less romantic than volunteers with normal serotonin activity.

Serotonin is mainly involved in mood regulation; control of basic activities such as eating, sleep and arousal; and control of pain. It also plays a role in memory formation.

“We wanted to see whether serotonin activity influences the judgements we make about peoples’ close personal relationships,” explained Oxford University professor Robert Rogers, who led the research, reports the journal Biological Psychiatry.

The approach involved giving amino-acid drinks to two groups of volunteers in order to manipulate blood concentrations of the amino-acid tryptophan, a vital ingredient in serotonin synthesis, according to an Oxford statement.

One group received drinks that contained tryptophan. The other group received drinks without this substance. They were then asked to make judgements about sets of photographs of couples.

Differences in the judgements made by the two groups reflected changes in their serotonin activity.

The volunteers who received the drink without tryptophan rated the couples in the photos as being less intimate and romantic than participants who received the control drink.

“Reduced capacity for intimacy can be a vexing symptom of many psychiatric disorders and an important target for treatment,” noted John Krystal, editor of Biological Psychiatry.