We all experience the occasional life-changing event—a new baby, a cross-country move, a serious injury. In rare cases, such events can precipitate a mental disorder. The problem is compounded because people often assume their suffering is par for the course after such upheaval. In reality, relief is probably a short treatment away, via therapy or medication.

The flashbacks, nightmares and sleep problems that mark post-traumatic stress disorder (PTSD) are usually associated with combat or other violent experiences. Now psychiatrists have found that PTSD can also result from being a patient in the intensive care unit (ICU) at a hospital, according to a recent study in the journal Psychological Medicine.

Researchers at Johns Hopkins University checked in with survivors of a lifethreatening lung injury for two years after they were discharged from the ICU. The investigators found that slightly more than one in three in the group suffered from the oftdebilitating anxiety disorder. Patients who had a history of depression were more likely to end up with PTSD after their hospital stay.

As is common in PTSD, the patients had flashbacks of their experiences, such as thinking they were going to die. But these cases were also unusual because the delirium caused by sedation and organ failure led to “nightmarelike” delusions and “distorted memories,” explains study lead author Joseph Bienvenu. The patients mistook a catheter in the bladder, for example, as a sexual assault, and reported “memories” of events that never occurred, such as plots to murder them.

The researchers say the high prevalence of PTSD after an ICU stay underscores the importance of following up with patients after they leave the hospital. Bienvenu says that he would not hesitate to prescribe treatment—either drugs or cognitive-behavior therapy—for an ICU patient with a history of depression while the person is still in the hospital.

More Unusual Causes of Mental Symptoms

Common life events occasionally lead to mental distress. If you think any of these scenarios might describe you or a loved one, tell a doctor: treatments today are more effective than ever.

Reading or hearing about a traumatic event may lead to a specific phobia, the persistent fear of a certain situation or object. Targeted exposure therapy has been shown to diminish, and perhaps erase, such phobias in a few sessions.

Bacterial infections, such as strep throat, may cause symptoms of obsessive-compulsive disorder in kids. Only a small subset of all OCD cases, which affect 3 percent of children, are thought to be caused by infections. Treatment with antibiotics cures most infected kids.

Eating more processed foods may be linked to experiencing greater levels of anxiety and depression. Avoiding grocery items with trans fats (hydrogenated oils) may help lift your mood.

Moving to a new house or school may trigger anorexia or bulimia in teens. Treatments such as talk therapy usually reverse the eating disorder.