A Lethal Inheritance

A couple of recent memoirs have focused on the author's quest to discover and chronicle a family history of mental illness, but I do not know of any that focus on the science behind this legacy with such meticulousness and precision as does Victoria Costello's new book, A Lethal Inheritance: A Mother Uncovers The Science Behind Three Generations of Mental Illness.

It's a tall order to do justice to several generations' psychic suffering while also explaining the pertinent scientific studies, but Costello does as promised. The end product is an impressive compendium, part family history, part memoir, part journalistic explication of the relevant research, and part anguished attempt to understand how Costello could have stood by while first one teenage son and then the other degenerated into mental illness.

Costello frames the book in the form of a psychic and spiritual quest spurred by her older son's confinement, at 18, to a "kiddie psych ward" when he suffers a psychotic break and is diagnosed with paranoid schizophrenia after several years of slow but obvious deterioration. Desensitized by her own lifelong depression, heavy drinking and impressive capacity for denial, Costello has managed to mistake her son's delinquency and drug use for adolescent rebellion, rather than the "negative," early signs of schizophrenia. His hospitalization forces her to confront not only the severity of his illness, but her own undiagnosed depression. After undergoing medication treatment, she begins searching for causes for their shared dysfunction.

What she finds is a heavy incidence of "genetic loading" that has greatly increased her own and her sons' risk of mental illness (her younger son is diagnosed with depression several years after his brother's schizophrenia diagnosis). Defying the common impulse to let family secrets lie, Costello begins excavating the past, reevaluating her father's alcoholism, her sister's drug abuse and probable undiagnosed bipolar disorder, her paternal grandfather's depression, drinking and likely suicide.

Unlike other memoirists who have chronicled their family histories of mental illness, however, Costello is not content to assume that what afflicts one generation must transmit, in some mysterious and unaccountable way, to the next. The chronology is a bit muddled, as are her exact reasons for delving so fiercely into the science (writing a book on the topic may have been a factor), but the upshot is that Costello examines large, carefully conducted longitudinal studies of the familial transmission of mental illness and presents them in great detail. She focuses in particular on those involving schizophrenia, perhaps because these are among the most rigorous and extensive compared to those on mood disorders, and perhaps because she is particularly tormented by her older son's suffering. In any case, her discussion of the studies is exhaustive, detailed, almost clinical.

Beginning her research, Costello had assumed that DNA was destiny, that one was stuck with the genetic cards one was dealt. Her thinking evolved, however, as did the science, over the decade that she investigated the subject, and she provides a fascinating look into some of the mitigating environmental factors that can both worsen and improve a child's chances of developing mental illness in the face of an increased genetic risk. Among them, in the case of psychotic illness, are heavy marijuana use during adolescence. But as her older son's story demonstrates, this presents something of a chicken-or-the-egg problem for parents and doctors trying to parse causes of an individual child's illness through the lens of hindsight. Troubled youths like her son who are already beginning to deteriorate are already more likely to abuse drugs; in a sad twist, however, if they carry increased risk of schizophrenia, they are now increasing their risk further several times over if they use narcotics.

Costello's discussion of the flurry of research into treating "pre-psychosis" is especially detailed and timely, and obviously a topic near to her heart, given her older son's experience. She provides a measured account of the continuing controversy over the use of antipsychotic medications in young people who have not yet begun to exhibit signs of full-blown psychosis, but wisely notes that tailored cognitive-behavioral therapy and other measures are also part of treatment programs, and that even low doses of medication have shown effectiveness in preliminary studies.

Costello makes a convincing case that knowing one's family history is key to deciding how aggressively to intervene in a child's or teenager's illness -- whether to interpret dysfunction as a passing phase or as a sign of more deterioration to come. She notes, shockingly, that although taking a family history is standard in many areas of physical medicine, it is not a feature of psychiatric diagnostics, despite ample evidence that family history determines everything from course of illness to response to treatments (on this last point I would have welcomed more extensive discussion).

Of course, family secrets remain just that -- secrets -- and patients' knowledge remains hampered by how well they can put together the missing pieces. Once they have gathered the information they can, what patients and doctors choose to do with it remains a judgment call, made in the context of other clinical factors. Still, Costello argues wisely, and with ample evidence as back-up, that it is safer and wiser to be armed with more information than less.

© 2012 Kaitlin Bell Barnett

Kaitlin Bell Barnett is a journalist and blogger based in Brooklyn. Her first book, Dosed: The Medication Generation Grows Up, comes out in April from Beacon Press.  It examines the experiences of young adults who came of age taking psychiatric meds.