The World Health Organization writes the following about suicide:
Over 800,000 people die due to suicide every year. ... By far the strongest risk factor for suicide is a previous suicide attempt. ... The prevention of suicide has not been adequately addressed due to a lack of awareness of suicide as a major public health problem and the taboo in many societies to openly discuss it.
For suicide attempt survivors, the general advice is to open up and talk about suicide.
When you are ready, it is important to talk about what has happened with people you trust. This allows others to be there for you and provides a chance to work out where to go from here. (BeyondBlue.com.au)
Aside from the general relief of simply having someone to talk to, other people should be aware of one's past suicide attempts so that they can help appropriately in the case of a future suicide attempt. It's best not to wait until you're at the brink before starting the discussion, as it's hard to speak coherently during these crises.
It is prohibited (haram) and sinful to talk about sins, whether current or past, except when there is a Shariah-countenanced reason. Even when such a reason exists, if it is possible to mention something general (such as not mentioning oneself or any particular type of sins) then mentioning specific sins would remain sinful. This is because it is: (1) obligatory to avoid vain talk, and (2) obligatory to conceal one’s sins. (SeekersHub)
Question: Is it okay to openly discuss one's past suicide attempts?
It may be that discussing one's past suicide attempts in an effort to safeguard against future attempts might be considered a "Shariah-countenanced reason", especially if suggested by medical professionals.
The most relevant search hit was a question Past Suicide Attempts Still Affect My Life to an Islamic counsellor who doesn't quite address talking about past attempts directly: "...my advice at this point would be to talk to your mom about these feelings and ask her to help you get therapy."