Post-traumatic stress disorder is a medical syndrome of psychological after-effects suffered by people who have been exposed to or have witnessed disasters or other distressing events. The extent of health problems of this kind among the Norwegian population has just been investigated for the first time. Photo: Katarzyna Bialasiewicz / Thinkstock

Scientists say 55,000 Norwegians suffer after-effects of trauma

The number of adults in Norway who suffer from PTSD is equivalent to practically an entire year class of Norwegians, claims a new study.

Disaster, rapes and threats. Sexual abuse, natural disasters and violence. Fear-arousing events such as these are what we call traumas. Some people who have experienced them subsequently suffer from health problems that physicians call post-traumatic stress disorder, or PTSD.

Eva Lassemo, a researcher at SINTEF Technology and Society, is part of a team that has carried out Norway’s first population study of PTSD.

Eva Lassemo, a researcher at SINTEF Technology and Society, is part of a team that has carried out Norway’s first population study of PTSD.

Typical symptoms include intrusive memories and nightmares, “numbness” and emotional blunting, reduced reactions to the environment, lack of feelings of pleasure and joy, distancing oneself from others and avoidance of situations that remind the victim of the trauma.

“Here in Norway, this is not a widespread illness, thankfully. But now we have shown that even in peaceful Norway, far more people suffer PTSD than, for example, lung cancer or bowel cancer,” says SINTEF health services researcher Eva Lassemo.

Symptoms that last for 11 years

Lassemo has been involved in Norway’s first population study of PTSD. She is lead author of a recent article in the journal “Social Psychiatry & Psychiatric Epidemiology”, in which she and three colleagues from the University of Tromsø, the Norwegian Cancer Register and Nordland County Hospital describe how they analysed the responses to interviews with a representative sample of the Norwegian population.

How the total figures are estimated

  • The study is based on interviews with a sample of Norwegian adults – a total of 1634 informants from the Søndre Nordstrand borough of Oslo and the four Lofoten municipalities in the County of Nordland.
  • A representative population sample was recruited, but the response rate varied between the age groups, and was particularly low among young men. The research group corrected for this so that each young male respondent counted as more than one person for the purpose of the count.
  • Based on the proportion of each age group in the total sample and of the total population of Norway, the researchers weighted the figures obtained from the study sample into figures for the total population.
  • When the research group subsequently estimated how many people experience a traumatic event or develop PTSD in the course of a year, they employed the concept of “person-year”. A forty-year-old informant contributed 40 person-years to the results of the study, while two sixty-year-olds
    contributed a total of 120 person-years.
  • The informants had been exposed to 1107 traumatic events, and 119 of them developed PTSD per 100,000 estimated person-years among the total population of Norway, i.e. out of 100,000 persons, 1107 experienced a traumatic event, and 119 of them developed PTSD in the course of a year.
  • This made it a simple task to find the corresponding figures for Norway’s 3.5 million adult inhabitants.
  • The study was financed by the Research Council of Norway.

Source: SINTEF

The data show that many people who suffer from PTSD are unable to find any quick-fix way of overcoming their problems. The people in the sample who had PTSD had struggled to deal with their symptoms for 11 years or more on average.

This has created an accumulation effect, since in addition to the new cases that occur every year, many people have not been able to rid themselves of a long-standing problem.

An entire birth cohort of sufferers

The data used by the research team was derived from standardised interviews that experienced interviewers held with 1600 Norwegians. In the course of conversations that lasted for between two and three hours, the informants provided answers; first, as to whether they had ever experienced traumas, and if so, when. Secondly, whether the traumas had resulted in unpleasant after-effects, and if so, from when. The third line of questioning concerned how long the medical consequences had lasted.

The researchers used standard statistical procedures (see fact-box) to transform the responses into figures representative of the total population of Norway. The results showed that every year, around 22,360 adult Norwegians are exposed to potentially traumatic situations, and that almost 2500 new cases of PTSD occur in the Norwegian population every year.

“After we had worked out the figure for the annual number of incident cases, we were able to estimate the prevalence for 2015, because we could also see how long the symptoms lasted on average. The final figure suggests that a total of almost 55,000 Norwegians were suffering from PTSD as recently as the year before last. This is equivalent to the total number of Norwegians born within the course of a year,” says Lassemo.


Women exposed to traumatic events are more likely to suffer PTSD than men

Type of trauma Percentage of women in the sample who experienced this trauma type, who subsequently developed PTSD (%) Percentage of men in the sample who experienced this trauma type, who subsequently developed PTSD (%)
1.    War event 4.4 6.3
2.    Physical threat (weapon) 33.5 2.8
3.    Rape 54.5 0.0
4.   Sexual abuse as child 53.6 36.6
5.   Natural catastrophe 3.7 9.1
6.   Serious accident 10.9 4.4
7.   Imprisoned, taken hostage, kidnapped 24.6 7.3
8.   Witnessed above events happen to others 17.0 3.5
9.   Verbal threat/ violence from close relation 40.4 38.0
10. Verbal threat/ violence from non-close relation 8.2 3.9
Two or more events 34.8 5.3

Women suffer more often than men do

  • It was already known that women who experience traumatic events are more likely to develop PTSD than men.
  • According to the Norwegian study, the likelihood that someone will suffer such an illness after exposure to trauma is four times as high among women as among men. Twenty per cent of the women who had been exposed to traumatic events developed PTSD, while the corresponding figure for men was five per cent.
  • No one knows for certain why women are more vulnerable in this field. One theory is that men participate in high-risk activities more frequently than women and therefore experience more, but less intense, potential traumas.

Source: SINTEF

The table is taken from the recent Norwegian study that shows how a representative sample of the Norwegian population reacted to traumas (frightening experiences). The figures show that women exposed to traumatic events are in general more likely to suffer post-traumatic problems than men who have had similar experiences. The exceptions are acts of war (in the case of the sample, these mostly involved experiences during the Second World War) and natural disasters.

Intentional acts are worst

The interviews that the study is based on were carried out by the University of Oslo, and the material will be a databank for researchers who wish to make use of it in the future. Since the interviews were held as long ago as 2000 and 2001 they reflect a Norway that had yet to experience the 2011 Utøya tragedy (when 69 young people at a Labour Party summer camp on the island of Utøya near Oslo were massacred by a lone ultra-right-wing terrorist), and that had not yet sent its soldiers to Iraq or Afghanistan.

The recent analyses of the interviews that were carried out by Lassemo and her colleagues, show that the risk of developing PTSD is greatest if the frightening event was deliberately directed at the victim.

“Our informants’ responses make it quite clear that people are less vulnerable if they are exposed to an unpleasant event that affects them accidentally or at random,” says Eva Lassemo.

Bright spot in the darkness

According to the health services researcher, the fact that deliberate acts are most likely to trigger stress is actually something of a bright spot. This is because such events can be prevented:

“Campaigns aimed at modifying attitudes can reduce the incidence of rape, and sexual abuse can be limited if awareness of the phenomenon is increased, while it is more difficult to do anything about the danger of being exposed to accidents or natural catastrophes.”

Contacting your doctor can help

Psychological disorders increase the risks

  • The study found that people who have suffered from anxiety or depression before their traumatic experience are at greater risk of developing a PTSD problem.
  • The Norwegian researchers found that among women, the absence of pre-trauma psychological problems offers a degree of protection towards PTSD. Such a relationship was not found in men.

Source: SINTEF

We do not know how many adults with PTSD are identified by Norwegian health services. This is primarily because diagnoses made by their regular physicians do not end up in a central archive.

“Do the data indicate that people who seek help from the health services get over their symptoms more quickly than those who don’t contact a doctor?

“We haven’t specifically studied this, but even without in-depth analyses, we can see that there is a tendency for people who contact their doctor following a traumatic experience to suffer from PTSD for a shorter period of time.”

Reliable sample?

“Can we be certain that studies of representative samples will give us reliable figures for the population as a whole?

“If you want to find out the full and complete truth about all the inhabitants of country, you will obtain the most faithful picture by interviewing each and every one of them. However, the world of research doesn’t have the resources to do anything like that. Certainly, the figures could have been a bit different if we had interviewed a different sample of 1600 people. But in theory, a representative sample ought to be a good reflection of a whole population.”

Lassemo explains that it is possible that some minor biases still remain, and she believes that this study may actually offer a slightly too positive picture of the real situation.

“Of all the persons who were asked to take part, 74 per cent said that they were willing to do so. There are good reasons to believe that these were among the healthiest of the people we contacted. Another thing is that people needed to understand Norwegian in order to be interviewed. On the other hand, the proportion of immigrants was lower in 2000 and 2001, when the interviews took place, than it is today. So all in all, there is reason to believe that the data give us a fairly good picture of Norway as it was, ten years before Utøya,” says Eva Lassemo.

Many unrecognised cases, says expert

In Stjørdal, in the County of Nord-Trøndelag in Mid Norway, psychiatric nurse Ann-Inger Leirtrø has led the city’s district psychiatric centre for the past ten years. She says that it will always be difficult to judge what proportion of people affected by PTSD are offered treatment.

“A lot of people are probably diagnosed with anxiety, depression or personality disorders without these being recognised as the result of a traumatic experience. This is because acts of violence and abuse committed by close relations are regarded as being so shameful and taboo that many victims are unwilling to mention them at all. For the same reason, many people continue to suffer from PTSD in silence, without even being identified and treated by the health services. All this means that many cases are not recorded,” says Leirtrø.

The number of cases of PTSD diagnosed by the specialist health service in Leirtrø’s own county of Nord-Trøndelag has risen from 128 in 2010 to 242 in 2016.

“Part of the reason for this increase is probably that many members of our treatment teams have taken courses in PTSD in the course of the past few years, which has made them more aware of this type of disorder,” says Ann-Inger Leirtrø.

This is post-traumatic stress disorder

The diagnostic guidelines for PTSD are:

Criterion A: stressor

The person has been exposed to a traumatic event in which both of the following have been present:

  1. The person has experienced, witnessed, or been confronted with an event or events that involve actual or threatened death or serious injury, or a threat to the physical integrity of oneself or others.
  2. The person's response involved intense fear, helplessness, or horror. Note: in children, it may be expressed instead by disorganized or agitated behavior.

Criterion B: intrusive recollection

The traumatic event is persistently re-experienced in at least one of the following ways:

  1. Recurrent and intrusive distressing recollections of the event, including images, thoughts, or perceptions. Note: in young children, repetitive play may occur in which themes or aspects of the trauma are expressed.
  2. Recurrent distressing dreams of the event. Note: in children, there may be frightening dreams without recognizable content
  3. Acting or feeling as if the traumatic event were recurring (includes a sense of reliving the experience, illusions, hallucinations, and dissociative flashback episodes, including those that occur upon awakening or when intoxicated). Note: in children, trauma-specific re-enactment may occur.
  4. Intense psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event.
  5. Physiologic reactivity upon exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event

Criterion C: avoidant/numbing

Persistent avoidance of stimuli associated with the trauma and numbing of general responsiveness (not present before the trauma), as indicated by at least three of the following:

  1. Efforts to avoid thoughts, feelings, or conversations associated with the trauma
  2. Efforts to avoid activities, places, or people that arouse recollections of the trauma
  3. Inability to recall an important aspect of the trauma
  4. Markedly diminished interest or participation in significant activities
  5. Feeling of detachment or estrangement from others
  6. Restricted range of affect (e.g., unable to have loving feelings)
  7. Sense of foreshortened future (e.g., does not expect to have a career, marriage, children, or a normal life span)

Criterion D: hyper-arousal

Persistent symptoms of increasing arousal (not present before the trauma), indicated by at least two of the following:

  1. Difficulty falling or staying asleep
  2. Irritability or outbursts of anger
  3. Difficulty concentrating
  4. Hyper-vigilance
  5. Exaggerated startle response

The professional literature suggests that PTSD is a temporary disorder. The symptoms are assumed to appear within six months of the date of the traumatic experience.

Source: The American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders (DSM-5)/WHO: International Statistical Classification of Diseases and Related Health Problems/SINTEF