Why love makes people nervous and unstable

Researchers hope that the discovery may also one day reveal why a few loved up people might overstep the mark when dealing with the object of their affections.

The frontal cortex, which is vital to judgment, shuts down when people fall in love.

The scans showed that this de-activation occurred only when someone is shown a photo of the person they adore, causing them to suspend all criticism or doubt.

"When you look at someone you are passionate about, some areas of the brain become active," the Daily Mail quoted Semir Zeki, professor of neuro-aesthetics at University College London, as saying.

"But a large part is de-activated, the part that plays a role in judgment," he said.

Someone in love will still be capable of making other major decisions in their lives, from striking a business deal to choosing a new mortgage and this very sanity makes it harder for their pals to convince them "they have taken leave of their senses" when it comes to an ill-advised affair.

The scans show that the area of brain that controls fear, and another regions involved in negative emotions, shut down, explaining why people feel so happy with the world - and unafraid of what may go wrong - when they are in love.

Studies showed that brain chemical dopamine is at higher levels in people in love.

Dopamine is key to people's experiences of pleasure and pain - linked to desire, addiction, euphoria - a rush may cause such acute feelings of reward that it makes love hard to give up.

Serotonin levels may fall in the same way to those seen in people with obsessive-compulsive disorder, explaining why love makes people feel anxious and jittery.

The love chemical that people are most familiar with is adrenaline. This hormone is the reason why our heart races, palms sweat and mouth goes dry, when we see the person we like.

The same hormone is also released when we are terrified.u00a0