The mothers-can-cause-it perspective has been through several shifts, as I've watched during my career, which began just as that point of view was falling out of favor. Here are some points on the progression that seem the highlights to me, though I'm not a student of this issue:

(Do I have any expertise in this area from which to speak, you might want to know? Not much, so my views should be taken as such. I did write a paper as a resident, when I was trying to explain all this history to myself, entitled A Brief History of Psychotherapy in Graphic Display (Academic Psychiatry, 1996; 20: 99-100/charts ) which emphasized a "big picture" view, from which I speak here).

2. As I was being trained, the mothers-can-cause-it perspective was waning in part simply because a more science-based tradition was gaining strength. As I recall, the mothers-hypothesis just slipped from view for a time.

3. Then the "science" perspective really took hold, continuing to the present. During that time, a "patient and family advocacy" movement also started, primarily with the efforts of the National Alliance for the Mentally Ill (NAMI). When this group acquired a national voice, one of the first things they did was to complain very strongly about the idea of a mothers-can-cause-it hypothesis with no real data behind it. And so that hypothesis became quite rapidly "politically incorrect".

4. In that context, it must have been very difficult for researchers to propose to test the idea that there was something families were doing that made the illness worse. However, slowly a new theory emerged: "expressed emotion". This suggested that in families where there was a lot of highly charged emotional expression (they left it that vague at first), patients would do worse. Note that this hypothesis did not attempt to blame parents for causing the illness, but -- as you note in your question -- they were suggesting that the family environment could "kindle" a small flame into a bigger one; and vice versa, that a different family environment could help keep the illness from progressing, or at least slower than in the other families.

Here we have a testable hypothesis, you see. And these researchers, who I regard as quite brave because of the political charge of the times in which they undertook this, did indeed demonstrate: a) that the hypothesis held up when families were compared, and their children's illness course monitored over time; and even more important, that (b) if the families were instructed on how to lower "expressed emotion", their children's illness seemed to be less severe. You can see that the latter is the real bombshell idea.

5. To jump rapidly to the present, the principle that teaching families how to change their communication will affect the course of bipolar disorder has very recently been proven true by the research teams of David Miklowitz. His book The Bipolar Survival Guide: What you and your family need to know explains this research and their results and tries to make the techniques they taught available to the general public.

In an odd way then, we've come full circle to showing that there is a glimmer of truth to Fromme-Reichman's idea -- not as a cause of bipolar disorder per se but as a course-modifier that can become part of the treatments that a patient and family should receive.