YOU DON’T have to be mad to be a parent, but it helps. In fact, according to a psychiatrist at Yale University, there are spectacular similarities between the thought processes of first-time parents and sufferers of obsessive compulsive disorder (OCD). Now he is speculating that OCD occurs when the brain circuits associated with parenting are triggered in the absence of a baby.

Professor James Leckman started researching OCD in the 1980s. His plan was to hunt down the neurotransmitter that might hold the key to OCD, in the same way that the neurotransmitter serotonin plays a role in depression. He did chemical analyses of the cerebrospinal fluid from OCD sufferers and found . . . nothing.

Rather than leave the samples languishing in the freezer, Leckman sent them off to another researcher to check for less well-known chemicals. “The guy who examined them was amazed by the levels of oxytocin,” Leckman says. Oxytocin is the hormone that tightens the parent-child bond. Knock out the oxytocin gene in female mice, and they lose the ability to nurse their young. Inject oxytocin into animals, and they show grooming behaviour and an increased faithfulness to one mate.

“The question was,” Leckman says, “what did all the behaviours associated with oxytocin, such as pair-bonding, have to do with OCD? Then I remembered how I behaved when my wife was pregnant with our first child. Every time she got a fever or a cold, I had these intrusive thoughts about harm coming to the baby. I remember my wife cleaning all the time, even moving the refrigerator. And even though I was a really busy medic, I found the time to build a cradle from scratch. I just came up with the idea that [parenting] is a normal, adaptive version of OCD.”

Leckman suggests that, given the high rates of infant mortality during human evolution, parents whose brains contained the neurocircuitry of paranoia would be most successful at keeping their offspring alive. When these circuits are switched on at the wrong time, he theorises, the obsessive behaviours become problematic and result in OCD. In particular, two variants of OCD — compulsive checking to ensure no harm comes to one’s family and an inordinate desire for cleanliness — are familiar to new parents.

Most recently, Leckman has questioned expectant parents and new parents on their feelings about their babies, using a method similar to that employed to diagnose OCD. He has found that just before and just after the birth the feelings and fears of both mothers and fathers are strikingly reminiscent of those voiced by OCD sufferers. He is keeping the exact results under wraps, and is preparing a paper for publication. Interestingly, Donald Winnicott, the late English psychoanalyst, commented in 1956 that, in order to relate to their infants, mothers develop a heightened sensitivity that is “almost an illness”.

• BARE-FACED lying takes some nerve. And so scientists have proved. The brains of pathological liars are structurally different from the brains of honest folk, and show more wiring. Deceit takes more mental effort than telling the truth, suggest the researchers at the University of Southern California, and this is borne out by the observation that the liars had about a quarter more white matter in their prefrontal lobes than honest people. The increased wiring imparts the enhanced cognitive and linguistic skills required to pull off a convincing con.

  The liars also had less grey matter than the others — this is the stuff that whirrs into action when people are asked to make moral decisions. Professor Adrian Raine, co-author of the paper in British Journal of Psychiatry, summarises: “They’ve got the equipment to lie, and they don’t have the disinhibition that the rest of us have in telling the big whoppers.”

• WANT TO lose weight? Acquiring a dog can lose you more weight in a year than most diet plans. Volunteers who walked dogs at least three times a week for a year shed 14lb. After the University of Missouri-Columbia study ended, several volunteers decided to get pets themselves or become walkers for dog shelters. Now Rebecca Johnson, who led the study, plans to study whether people would get more out of gym visits if they took along pets as “support companions”. Butch doing bench presses? Barking.

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