As an addiction and mental-health treatment specialist who has worked for decades with addicts and their families, I admit that in the past I have espoused this outdated and potentially harmful opinion. This is the stance I was taught to take, both in school and in my continuing professional education. In trainings I was told, “If a loved one cannot emotionally detach from an active addict, that person will be dragged down into the murky depths of despair. Thus, loved ones must be coached to let go.” So when I saw spouses, family members, and friends refuse to distance themselves from an active addict, I told them they were enmeshed and codependent, and encouraged them to detach. Unfortunately, this tactic ignores the ways in which human beings are wired for survival.

This gives us an insight that goes much deeper than the need to understand addicts. Professor Peter Cohen argues that human beings have a deep need to bond and form connections. It’s how we get our satisfaction. If we can’t connect with each other, we will connect with anything we can find — the whirr of a roulette wheel or the prick of a syringe. He says we should stop talking about ‘addiction’ altogether, and instead call it ‘bonding.’ A heroin addict has bonded with heroin because she couldn’t bond as fully with anything else.

The growth of the baby’s brain “literally requires positive interaction between mother and infant. The development of cerebral circuits depends on it.” Prof Schore points out that if a baby is not treated properly in the first two years of life, the genes for various aspects of brain function, including intelligence, cannot operate, and may not even come into existence. Nature and nurture cannot be disentangled: the genes a baby has will be profoundly affected by the way it is treated.The damage caused by neglect and other forms of abuse comes by degrees: the more severe the neglect, the greater the damage. 80% of brain cells that a person will ever have are manufactured during the first two years after birth. If the process of building brain cells and connections between them goes wrong, the deficits are permanent.