[user104658]

Most places still have strict regulations on when ECT can be used, it can only be used "freely" in certain in-patient clinical settings (e.g. If you've been held involuntarily on the grounds of the Mental Health Act). Of course even then it's a voluntary treatment.

It is apparently very effective, it can completely alleviate some forms of clinical depression for some people for a short period of time (sometimes weeks) and offer respite in that way. Also providing that glimpse of the "light at the end of the tunnel" can help people overall, if they've lost sight of what feeling OK actually feels like.

The main issue with it is that the effect is temporary... It wears off after a while and has to be repeated. Also, every time its repeated it becomes less effective (doesn't last as long) so eventually it becomes impractical as an ongoing treatment...

It also varies massively from person to person with some people having massive relief, and others it not doing anything at all.

The procedure itself, apparently, can be distressing for observers but not for the patient themself these days as its done under heavy sedation. But it basically triggers seizures so for anyone watching, it seems pretty barbaric... And obviously was pretty barbaric in the past when it was a less refined procedure and sedation wasn't always used.