Roberta Fleeton said she was left with the condition after being stabbed and left for dead aged 13 as part of The Troubles in Belfast, where she grew up.
Aged 42, it was made worse when Isabelle Lewis, 38, was murdered and mutilated by her neighbour Keith Valentine and her body parts were found on the Addington Court golf course in Croydon.
He was sentenced to life in prison at the Old Bailey in 2000 - but in October 2017 he was granted parole, Roberta said.
The 62-year-old said: "I am gutted. Destroyed. His crime was so bad."
The stress of this event was followed by a string of serious criminal incidents last year in Lawrence Avenue, Rustington, where she has lived for 17 years - and has left Roberta struggling to sleep, suffering night terrors and harming her mental health.
A bungalow was burnt down in September - and on Christmas Eve, a man was attacked with a machete and armed police swarmed the street.
She said: "I went into my bedroom and hid in there, in fear of it spreading."
A car fire on Boxing Day was followed by a series of smaller incidents, Roberta claimed, which have left her scared to go outside. Since the New Year, she said she had left her home on only a handful of occasions, to see her doctor and dentist.
She said: "This was a really great street to live in before, but now I don't feel comfortable past my own front door. I don't know when it is all going to kick off."
As she is on the housing register, she asked Arun District Council to move her to Littlehampton so she could be nearer to her 43-year-old son.
They offered her a maisonette, but she turned it down as flats reminded her too much of the set-up between her sister and Valentine, who both lived in the same block, she said.
A spokesman for Arun District Council said: “We are aware that there has been some anti-social behaviour of a serious nature in the area and the police and council have been working on these matters.
“We are working with Ms Fleeton to offer support and to try to find a solution to her situation.”
A spokesman for the Parole Board confirmed it had approved the release of Keith Valentine following an oral hearing in October 2017.
He said: “Parole Board decisions are solely focused on whether a prisoner would represent a significant risk to the public after release. The panel will have carefully looked at a whole range of evidence, including details of the original evidence and any evidence of behaviour change.
“We do that with great care and public safety is our number one priority.”
Inspector Sharon Sawyer said: “We are aware of some recent issues in Lawrence Avenue in Rustington and have been investigating these incidents. Anyone who has concerns can speak to us.”