What is the 'bad place' the protagonists come from in Shame?

Question

In Shame, Sissy tells Brandon

We're not bad people. We just come from a bad place.

I assumed that this bad place may have meant they were abused as children by their parents, which led to Brandon's sex addiction and overall behavior, and Sissy's not wanting to return home ever again.

Is there any asserted basis for my assumption? Do we know what bad place they came from?

Answer 1

The assumption is more or less correct if we see Brandon and her sisters relation simple and basis are:

1. His complete disbelief in relationship and marriage which shows that he cannot imagine a happy family life because he hasn't witnessed any.
2. Her sister's suicide attempt. She has cut-marks on her wrists that seem deep enough to be fatal and she states them as "she was bored" so she did it.
3. (His avoiding his sister. He thinks she isn't his responsibility and now she is a burden) <- Not sure if this ones the correct argument for this question.