Both women were said to be suffering from Diogenes syndrome, also known as senile squalor syndrome, which is characterised by such actions as compulsive hoarding of rubbish.

BBC: Mental illness 'affected' death accused Angela Pearson

But when seemingly useless possessions and even rotten food pile up, blocking exits and filling beds, sofas, sinks and bathtubs, it's evidence of a psychiatric condition called compulsive hoarding.

WSJ: Compulsive Hoarding Affects up to 2% of the Population

And despite the fact that hoarding has traditionally been seen as a symptom or subtype of obsessive compulsive disorder (OCD), brain activity in those who cannot de-clutter is also distinct from that of people with typical OCD, the study shows.

CNN: STORY HIGHLIGHTS