So sorry ECTQ for you and your mom. I suffered a severe depressive episode Easter 2010 and was on a psych ward for 3 months. I was in the "Older people's Ward" as I was 66. I began to hear people talking about ECT and I was shocked and thought this belonged in the past, having seen all those pictures of people violently shaking etc. However I began to realise that several women on the ward were having ECT. My psychiatrist (who wasn't approachable) had a Junior Dr doing a placement with him for 3 months and he spent loads of time withme. I brought up the issue of ECT and how surprised I was it was still a treatment. He told me that it was a very effective treatment for severe depression with psychotic episode (which maybe your mom has I don't know) or drug resistant depression.
I saw women coming back from ECT and I didn't get the impression they had had a GA - in fact I think the Jr Dr told me that they are given a sedative and don't feel any pain. They certainly seemed ok when they came back to the ward and just maybe a bit sleepy but as some of the patients were quite elderly this wasn't uncommon. I talked about it to the Ward Manager as well and she said if she became mentally ill and nothing else worked she would not hesitate in having ECT and she talked about how people remember all the horrid stuff in the 70s and how things had changed so much now.
You mentioned that your mom was much worse after being taken off lithium which I think is the usual drug for bi-polar? why was she taken off it - do you know. I think it can sometimes affect the kidneys, but not sure. You say your mom is "very insane" and she doesn't realise she is ill, so surely she is psychotic, as in out of touch with reality. I am realy surprised that she is being treated at home, by CPNs presumably. Thing is these awful cuts have put such pressure on the NHS (and other public services) that people like your mom who need admission can't get it. I think (though am not sure) that if you do have ECT you need to be an inpatient. If you can talk more to your mom about the modern ECT and maybe help her to feel less afraid (though if she is psychotic she won't be thinking clearly) she may be more accepting.
You say the psychiatrist has given you all the pros and cons. I think that your mom is only going to get worse isn't she, so maybe ECT is a better option than getting worse. You mention the psychiatrist is going to give her a mental health act if she doesn't agree to ECT. I assume you mean a Section under the MH Act, as has happened before, and in my view the safets place for a person with psychosis is in hospital. I think that treatments can be given without the patient's permission under a section but am not sure, and don't know if this applies to ECT.
My advice would be to harden your heart and try and get your mom to accept ECT (called tough love) and if this means that she gets admitted allthe better. Your psychiatrist sounds like he/she is helpful, so maybe ask the CPNs to refer your mom to the psychiatrist again, although this probably isn't necessary as she is already one of his patients.
I know from first hand the torment of mental illness and the way people don't understand and the stigma attached to it - it all makes everything so much worse than physicall illnesses.
Hope your mom gets the help and support she deserves. 70 is not old these days.