Getting back to the original points, the best and most comprehensive analysis of the litterature on the question "can we predict suicide in a clinically meaningful way?" says "definitely not" and even argues that attempting to do so may lead to more harm than benefit and recommends again the practice.
#### What you need to know In the UK, one in five adults has considered suicide at some time, and one in 15 has attempted suicide.1 Half of those who attempt suicide seek help afterwards—a quarter from a GP, a quarter from a hospital or specialist medical or psychiatric service.1 Suicidal...
www.bmj.com
Two side notes:
1) Using SA as a proxy for suicide is terrible methodology because SA gleaned from medical records are often not deliberate attempts to ends ones life with actual potential harm beyond typical daily activities and also likely include reported "attempts" by malingerers. Research where suicide is not the primary outcome is not research on suicide prediction.
2) A factor should only be described as modifiable if there is direct evidence that modifying that factor actually reduces the rate of completed suicide. For example, there is evidence that lithium reduces risk of suicide in the long term in BP1. Therefore, BP1 without lithium tx could be considered a modifiable long term factor. Owning a gun? Unclear. I imagine most homes have several easy means of suicide (belt, Tylenol/nsaids/iron, knife and internet for where to stab, lethal height buildings are available in most cities). Is owning a gun a risk factor for suicide because people who own guns have a lower threshold to kill, are more likely to have experienced violence/trauma (military, police), or because of the easy access to an easy means. I suspect all three have some role, but there needs to be a direct link between removing a gun and decreasing suicide rates driven by a randomized trial to say it's "modifiable;" until then it's an associated factor. Curiously, gun ownership has been decreasing steadily in the US while suicides increase and the implementation of the SAFE act in NY has seen a leveling and very slight decrease in rates of suicide but certainly not close to a return to the heyday of mental well-being in the early-mid 00s. I'd love to see a high quality study on these interventions if anyone has one to suggest.
Of course, I'm not suggesting that you won't lose a malpractice case when you argue that all of the science says that suicide in not predictable in a meaningful way... because a dozen psychiatrists will certainly testify that all of this is "standard of care" even though it's snake oil and juries will probably buy it.