Gabor Maté - In the Realm of Hungry Ghosts - Close Encounters with Addiction

That leaves one final line of defence for the genetically minded: twin studies in which identical twins are separated at birth and brought up in different families, neither family being the biological one. Surely here the similarities must be all genetic, the differences environmental. The two members of such a twin pair live in different families and are therefore exposed to different environments, while obviously, they continue to have the same genes. It follows that any similarities must be dictated by genes and any differences, by their rearing environment. So, at least, a genetic perspective would dictate. Thus the platinum standard of genetic studies is ostensibly provided by studies of identical twins who are adopted and brought up by different parents, in different families. We are back to adoption, and the genetic argument is no sounder here than it was before.

It’s not the case that identical twins brought up by different adoptive parents did not share the same formative environment. They spent nine months in the same uterus, exposed to the same diet, same hormones and same “messenger” chemicals. At birth they were both separated from the birth mother—the very opposite of the natural agenda which has the mammalian infant immediately latch onto the mother’s breast. By birth infants are sensitized to their mother’s biorhythms, voice, heartbeat, energy. Being torn away from that familiar environment adds trauma to the profound but necessary shock of being expelled from the uterus. **39We know from animal studies that early weaning can have an influence on later substance intake: rat pups weaned from their mothers at two weeks of age had, as adults, a greater propensity to drink alcohol than pups weaned just a week later, at three weeks of age. 9No wonder that adopted children are generally more vulnerable to various developmental disorders—for example, ADHD—that increase the risk for addiction. No wonder that many adults who were adopted as infants harbour a powerful and lifelong sense of rejection or that among adoptees the adolescent suicide risk is double that of nonadopted children. 10

Finally, we have seen the pivotal necessity of a consistently present, emotionally available parenting caregiver for proper brain development. But in some studies the adoption does not happen immediately after birth—the infants may be in a hospital, cared for by nurses who work, at most, twelve-hour shifts and who come and go in the infant’s life with bewildering irregularity. Other adoptees are cared for by foster parents, only to lose those familiar faces at the moment of adoption. Taking all these factors into account, the assumption of a nonshared formative environment is lopsided, to say the least. All in all, identical twins slated for adoption have shared major environmental influences before the adoption takes place.

There is one more important environmental factor at play here. The world is much more likely to respond in similar ways to identical twins—same gender, same inherited tendencies and identical physical features—than to fraternal twins, who may be of different gender and have very different looks and very different reactivity patterns. In other words, for identical twins the environmental factors are still more likely to be similar, even after adoption into different families.

Thus, adoption studies of identical twins can tell us much less about genetic effects than researchers have taken for granted.

Even the authors of another influential twin alcoholism study, who lean strongly toward genetic interpretations, wrote that “at this point we are not certain that anything is inherited.” 11

APPENDIX II

A Close Link: Attention Deficit Disorder and Addictions

The reader may have noticed that many of the patients I have described or quoted in this book have lifelong histories of attention deficit (hyperactivity) disorder, also known as ADHD (or ADD, if the hyperactivity trait is not present). It is common practice, although a bit confusing, to use the two acronyms interchangeably. For the sake of simplicity I’ll employ ADHD as the defining term here, as long as we keep in mind that the hyperactivity may or may not be present. In addicted males especially, it often is.

Diagnosing ADHD in cocaine and amphetamine addicts is tricky, because the drugs themselves will drive physical and mental hyperactivity and disorganization. Under the influence of cocaine or crystal meth, a normally sedate person may resemble someone with severe ADHD. The other complicating factor is that, from adolescence onward, people with ADHD are at an elevated risk for addiction to cocaine and other stimulants. It becomes difficult to sort out what came first: addiction or ADHD. Having attention deficit disorder myself, I have an intuitive feel for recognizing the condition in others, but the diagnostic key is the history of ADHD symptoms since childhood, predating the drug use.

ADHD is a major predisposing factor for addiction, but it is frequently missed by physicians. I have been struck by how often addicted patients of mine with self-evident ADHD traits have eluded diagnosis throughout childhood and well into their adult years. Some others were diagnosed as children but never seem to have received consistent treatment. In very few cases have any of them been treated for the condition as adults. A Yale University study has shown that among cocaine users with ADHD, those who are treated only for their addiction but not for their predisposing ADHD don’t do as well. In this Yale study as many as 35 per cent of cocaine users who presented for treatment met the diagnostic criteria for childhood ADHD. 1In another study, as many as 40 per cent of adult alcoholics were found to have underlying attention deficit (hyperactivity) disorder. 2People with ADHD are twice as likely as others to fall into substance abuse and nearly four times as likely as others to move from alcohol to other psychoactive drugs. 3People with ADHD are also more likely to smoke, to gamble and to have any number of other addictive behaviours. Among crystal meth addicts a significant minority, 30 per cent or more, also have lifelong ADHD. 4

The link between ADHD and a predisposition to addiction is obvious and, in fact, inevitable. The connection has little to do with genetics. ADHD is no more inherited genetically than addiction is, despite the widespread assumption among ADHD experts that it’s “the most heritable of all mental disorders.” The same facts that make twin and adoption studies largely irrelevant to the understanding of addiction also discredit the genetic theories regarding ADHD. There’s no need to repeat them here. The basic point is that ADHD and addictive tendencies both arise out of stressful early childhood experience. Although there is likely some genetic predisposition toward ADHD, a predisposition is far from the same as a predetermination. Two children with similar predispositions will not automatically develop the same way—once more, the environment is decisive.

The brain developmental information regarding ADHD is presented in my book Scattered Minds: A New Look at the Origins and Healing of Attention Deficit Disorder. *40Scientific findings since then have only confirmed that pre-and post-natal stresses are the most important determinants of this condition. According to one recent study, for example, 22 per cent of ADHD symptoms in eight-and nine-year-old children can be directly linked to maternal anxiety during pregnancy. 5Abused children are far more likely than others to be diagnosed with ADHD, and the same brain structures affected by childhood trauma are most consistently abnormal in scans of children with ADHD. 6

My point is not that abuse is the cause of ADHD, although it certainly increases the risk for it, but that early childhood stress is the major factor—abuse being only an extreme form of childhood stress. It is the impact of early stress on the brain—maternal depression, for example—that creates vulnerability to ADHD and to addictions. Stresses or interruptions in the infant–mother relationship lead to permanent alterations in the dopamine systems of the mid-brain and prefontal cortex, disturbances that are implicated in both ADHD and in substance abuse and other addictions. 7If the prevalence of ADHD and other childhood developmental problems is rising in our society, it is not because of “bad parenting,” but because the burgeoning stresses on the parenting environment appear to increase with each successive generation. Parents, and mothers in particular, are getting less and less of the support they need during their children’s early years. The issue is not one of individual parental failure, but rather of a social and cultural breakdown of cataclysmic proportions.