PTSD creates a vicious circle by worsening the Crohn’s symptoms, indicates the study.

Crohn’s disease is incurable and can potentially affect the entire digestive tract, producing severe pain and diarrhoea. it is particularly common in Northern Europe, including the UK, and North America.

Its precise cause is not known, but its unpredictability makes it difficult to treat, and treatment is itself expensive, exhausting, and onerous, and carries its own risk of complications, say the authors.

The researchers tracked the health and psychological wellbeing of almost 600 adults over a period of 18 months. All of them had been diagnosed with Crohn’s disease and lived in various different locations in Switzerland.

At the start of the study, each patient’s mental health was assessed using a 17-item validated PTSD scale, which scores the degree of fear, suffering and impaired quality of life associated with PTSD from 0 to 51.

A score of 15 or more points is suggestive of post traumatic stress disorder, and almost one in five (19%) of the patients achieved this score.

The worsening of symptoms was then monitored during the subsequent 18 months to see if there was any link with the scores and a diagnosis of PSTD.

The results showed that those individuals with PSTD were more than four times as likely to experience worsening symptoms as those who scored below this threshold, and more than 13 times as likely to do so as those scoring zero.

Post traumatic stress occurs in response to traumatic experiences, and is typically manifest in recurring dreams/thoughts, avoidance tactics, irritability and sleeping difficulties.

It is normally associated with violence, emergency situations and natural disasters, but increasingly, research indicates that particular illnesses, such as cancer and HIV infection, plus the diagnostic and treatment procedures that accompany them, also take a hefty emotional toll, say the authors.

They add that over the long term, post traumatic stress permanently changes the body’s hormonal and immune responses, so making the sufferer potentially more prone to serious ill health.

“In most cases patients avoid talking about cures which remind them of having the disease…Such behaviour may unwillingly be encouraged by the usual shortness of consultation time and unfamiliarity of [gut specialists] in dealing with the psychological needs of their patients,” warn the authors.

Crohn’s disease can’t be cured, but PTSD can, and doctors should be alert to the psychological fall-out and refer patients for appropriate therapy, they suggest.