30 minutes or less of question-and-answer about the family history of depression, anxiety, or substance abuse is enough to predict a patient’s approximate risks for developing each disorder and how severe their future illness is likely to be.
“There are lots of kids with behavior problems who may outgrow them on their own without medication, versus the minority with mental illnesses that need treatment[.] . . . Family history is the quickest and cheapest way to sort that out.” . . .
[In one study] each individual’s personal experience with depression, anxiety, alcohol dependence and drug dependence in relation to their family history “scores” – the proportion of their grandparents, parents and siblings over age 10 who were affected.
The analysis shows that family history can predict a more recurrent course of each of the four disorders. It is also indicative of those more likely to suffer a worse impairment and to make greater use of mental health services. Contrary to earlier reports, those with a stronger family history did not necessarily develop their disorders at an earlier age.
Japanese match makers have long used similar family histories in their practice.
The good news is that something cheap and quick can have significant diagnostic value. The bad news is that this kind of screening test invites use for actuarial purposes to set health insurance rates, to match making, to sentencing decisions, yet shows only a likelihood that problems will come up. Some people, who have family histories of conditions, but have not inherited them for some reason, may be treated as if they did when these measures are used.
If family history matters and is used routinely, there is an incentive to cover up conditions to protect other family members from discrimination. This gives the conditions themselves a social element of shame.
Also, while most people know the names of their putative ancestors, often the details about what kind of people those ancestors were are prone to distortion in the retelling on points that don't fit easily into a designated category. Words are malleable. For example, impulsivity can have a variety of distinct meanings (such as sensation seeking, lack of perseverance, lack of planning, acting without thinking) that would be important in putting together a family mental health history, in addition to varying by degree. What may be exceptional in the general population, may different compared to other family members. So, even if you had a relative known for being the impulsive one in the family, that might not be easily to translate into a family mental health history. Yet, psychological questionaires often use vague terms like impulsivity, and vague words to define the degree of a trait, rather than concrete descriptions that operationalize a trait. I have no idea what psychological quirks my grandparents had for the most part, even though I knew them as a child (all of my grandparents have died at this point in my life).
Importance attached to this kind of family history also makes relevant the fact that many people have accepted lineages that are inaccurate or incomplete. Affairs may produce paternities that aren't those that are officially presumed. People may have siblings that they've never been told about.
Still, simply ignoring diagnostically powerful information is problematic as well. If you know that three out of four of a person's grandparents suffered from alcoholism, that both of their parents are heavy drinkers, and that some of their aunts and uncles have had alcohol problems, one might appropriately develop a different attitude towards addressing substance abuse issues with that child than one might with a child who has no family history of alcoholism, heavy alcohol use or substance abuse. Knowing that someone is "at risk" can influence their behavior and patterns of treatment if a problem develops.