Being mugged or randomly attacked in the street often leaves people paranoid and distrustful of others long after the attack, according to a study published today. The research highlights a previously under-recognised consequence of physical assault which will help to inform therapy for those seeking help.

In the study, four out of five victims reported that since the assault they were more fearful of other people than they wanted to be. Importantly the study identified what led to excessive mistrust lasting over the next six months. Being attacked close to home, feeling defeated at the time, worrying excessively afterwards, feeling unsupported by others, and difficulties sleeping all meant paranoid fears remained in a person’s mind.

It’s well known that being physically assaulted can lead to symptoms of post-traumatic stress disorder (PTSD). This is the first study to assess for feelings of paranoia, an excessive mistrust of other people, in the months after an attack. It was found that the victims’ fears about their attacker often spread to thoughts about other people, such that they had become wary of many people around them. Half of the study participants said that since the assault they felt fearful of all females, and two thirds said that they felt fearful of all males. One in ten had very high levels of paranoia in the months after the assault.

The study, funded by the Wellcome Trust, followed 106 people who had attended hospital with minor injuries after a physical assault and monitored them over the next six months for symptoms of PTSD and paranoia.

The paranoia was assessed in multiple ways by the study psychologists. They used self-reporting, careful interviewing by trained assessors, and an innovative virtual reality test to monitor how the participants perceive neutral computer characters. The team showed that the fears even transferred to virtual reality computer representations of people.

Professor Daniel Freeman from the University of Oxford, who led the study whilst at the Institute of Psychiatry, King’s College London, said: “It is very understandable that being attacked makes us wary of the people around us. Our mindset may become more like that of a bodyguard, vigilant for danger. When we are overly mistrustful, that is a form of paranoia. It may well be a normal temporary change in our thinking after being a victim of attack. The danger of such thoughts, however, is if we isolate ourselves, close off from others, and spend our time thinking only of the worst. It is an under-recognised problem in the aftermath of an attack.

“For many people the fears about others gradually ease with time. But our team identified several key factors both during and after the assault that made the paranoid fears much more likely to remain. If we are attacked in places or by people we know, that leads to greater mistrust than being attacked by a stranger or in unfamiliar places. The trust we had becomes broken. If during the assault we feel destroyed as a person or we become detached from ourselves then mistrust typically stays for longer. Afterwards if we feel down on ourselves, ruminate and worry, and start to take excessive precautions, then fears will stay in mind. Conversely it looks likely that we benefit from good sleep and feeling supported by those around us.”

Professor Anke Ehlers, a PTSD expert at the University of Oxford who collaborated on the study, commented: “During the last decade, significant progress has been made in understanding the factors that predict who will develop PTSD after assault, and this has helped improve the effectiveness of psychological treatments. The finding that many of these factors also predict paranoia opens up new avenues for treatment.”

Summing up the study, Professor Freeman concluded: “Traditionally it was thought paranoid thinking was rare in the aftermath of an attack. It was thought that paranoia only occurred in severe cases of PTSD. However fears about other people may well actually be typical. If you have been attacked, these sorts of thoughts are to be expected. And paranoid thoughts are much more likely to remain depending upon how we respond both during and after the attack. We plan to use this information to improve the latest generation of cognitive behaviour therapies for those seeking help.”

The study is published today, Wednesday 27 March, in the journal Psychological Medicine.