How likely is that a second schizophrenic episode will happen?

Can a woman, my sister, who had only one schizophrenic episode due to marijuana abuse (early 20s) accompanied by a suicide attempt and diagnose of bipolar when discharged from a psychiatric hospital, lead a normal life without any treatment AT ALL since? She suffered childhood traumas, today 35 years old, has always been difficult to relate emotionally unstable and accumulated several conflicted personal relationships in all aspects of her life. How likely is that a second episode will happen? She does not accept psychological help and distance herself when the family tries to help. Any advice for family members?

Recurrances are actually very likely, I believe. Though I have read of people with bipolar disorder only having a few episodes in their lives, I believe that is definitely not the norm. There are many of us with bipolar disorder that have numerous episodes, sometimes more than one can remember. My bipolar illness worsened as I aged from being unmedicated.

If a person has schizoaffective disorder, I'd think that the illness course would be even worse, at least as the schizophrenic symptoms go. That's something to ask a mental health professional. If a doctor says the schizophrenic symptoms were likely only caused by marijuana abuse, that could yield a possibly different answer. Again, your sister's psychiatrist should be the one to answer this question. Is she still using marijuana?

My husband's nephew was hospitalized years ago and diagnosed with schizophrenia, but not bipolar disorder, but later it was found that he didn't have schizophrenia, but that severe marijuana abuse was indeed the culprit for his experience. He stopped using marijuana completely and the hallucinations disappeared. For this reason, I urge people to not use marijuana, especially not without a doctor's direction or in extreme moderation.

Thank you! But that is the issue... she does not accept help, neither from therapists. Many years ago, when she saw a therapist she stopped as soon as the professional mentioned that some of her behaviours were not "good for her" - she blames everyone around her, does not take ANY blame or constructive criticism (does not matter how careful you put it). When she is completely by herself, feeling down, she seeks my company until she decides to accuse me of unbelievable things - betrail, lying to her, the smallest thing is a massive issue - basically gets really paranoid when she is into any kind of relationship, even work.
Is this a sign that she may, depending on the trigger, fall into another episode? I do fear for her life as she does not have support or accept support.
Any suggestions?

Unfortunately, you can't help someone who doesn't want help, because as you've seen, she's not getting better as long as she refuses help. However (!), you can always continue extend your hand, saying you're there if she needs you. Offering support can help people with mental illness, but at the same time, there is a fine line between abusive behavior and behavior that arises from a mental illness.

Maybe I'm wrong, but I've never seen "blaming" or "lying" as symptoms of bipolar, schizophrenia, or schizoaffective. (I'm not saying you're saying they're symptoms, but I think they fall under abusive behavior and likely have nothing to do with her mental illness. Sure, she could be frustrated and that frustration is let out that way, but I would call it a personality issue, and it's not fair to you or anyone else around you to get abused.)

What Blue said.

There may be other things going on and her not wanting to change isn't going to help.

You may need to set some boundaries with her and let her go with compassion when she goes past them. Like, "I'll listen to you but I'm hanging up (or leaving) when you start abusing me." And follow through with it.

Thank you!

I do not know exactly what are the symptoms... But I can try to describe in one word - paranoia.
Say - she worked as a nanny for a little while - the family would ask her if the child had eaten or not (what I assume to be absolutely reasonable) it would make her believe that the family were suspecting that she was not "trying to feed" the child, then she would tell me, I would say that she should not feel uncomfortable, its nothing behind a simple question, then she would say to me that she was suspecting that the family had cameras on the house without her knowledge, my answer was: ask them, they can if you agree or have suspicions from you, etc - bot stop worrying if you are doing nothing wrong... this would go on and on for weeks until she finally argues with the family (for about 10 more reasons by then) and leave... But every conversation about this matter with me was very stressful because she would say that I was not believing her, etc
Her boyfriendS - poor them all - she even accused me of having feelings for one guy because I knew him from high school, so I could not be around him without her presence.
There were several occasions with me, other family members, friends, boyfriends, work etc... and she how can not see that?
is it a symptom?

Her schizophrenic episode was a lot more than just "paranoia" she had hallucinations, heard voices mostly, left the house naked, and tried to end her life.

Ive had those things but not all at once.