On the anniversary of traumatic events, some people may find that they experience an increase in distressing memories of the event. These memories may be triggered by reminders, but memories may also seem to come from out of the blue while at work, home, or doing recreational activities. An increase in distress around the anniversary of a traumatic event is commonly known as an "anniversary reaction" and can range from feeling mildly upset for a day or two to a more extreme reaction in which an individual experiences significant psychiatric or medical symptoms.
An anniversary reaction can occur because the date of the original trauma (or some other trigger) activates a traumatic memory. In a case such as the September 11, 2001 attacks, the date itself may serve as an especially strong trigger. Because the attacks were labeled with the date on which they occurred, it is nearly impossible for any adult who was affected to go through that day unaware of its significance.
One theory about why anniversary reactions occur is based on the way traumatic experiences are represented in memory. According to Foa and Kozak (1), traumatic memories contain specific information about the dangerousness of an event so that people will seek safety and protect themselves from similar harm. The memory provides information about what the individual should be afraid of, how he or she should perceive such situations, how to feel in that situation, and what to think.
For example, a traumatic memory of a rape might contain the information that it is important to be afraid of strangers at night, run away if approached, feel frightened, and think one is in danger and needs help. The anniversary of an event can trigger a traumatic memory that produces these kinds of strong emotions as well as physiological reactions, negative thoughts about the world, and protective coping responses.
A common type of anniversary reaction is experiencing grief and sadness around the anniversary of the death of someone significant. In fact, this is common enough that most major religions have commemorative ceremonies to support those who feel increased grief at these times. At the extreme end of the spectrum, people can find themselves clinically depressed or even suicidal. However, for most, the episode of flattened affect and sadness is brief.
Symptoms of anniversary reactions to traumatic events can be understood as an exacerbation of the symptoms that define PTSD. These include symptoms of intrusion, avoidance, negative alterations in cognitions and mood, and arousal and reactivity.
Other types of anniversary reactions may involve anxiety symptoms such as panic, specific fears, or worry. Individuals may have panic attacks, be afraid to go certain places, or find that they worry about their safety and the safety of their loved ones. Others may experience physical (or medical) symptoms such as fatigue and pain or general health complaints such as headaches and stomachaches.
What becomes obvious is that there is not one classic anniversary reaction. How the anniversary reaction presents itself will vary for different people. It may depend on the type of traumatic experience, on the time since the original trauma or loss, on the characteristics of the individual, or other factors.
There are few empirical studies of anniversary reactions. These studies tend to be small convenience samples. In general, empirical studies show small increases in distress at the time of the trauma anniversary (2-5).
The best studies of anniversary reactions are longitudinal studies that continue to assess symptom experience post-anniversary and show symptom decline following the annual reminder. In a series of studies, Morgan and colleagues examined anniversary reactions in Operations Desert Storm and Desert Shield Veterans two and six years after the end of these conflicts (6-7). The researchers asked the Veterans and their wives to identify the Veteran's worst month of functioning in the past year. When the researchers compared the worst month identified to previously identified dates of traumatic events that occurred during the Operations Desert Storm and Desert Shield, they found that 38% of participants reported that their worst month coincided with the month in which their trauma occurred (6). Veterans with these anniversary reactions had significantly more PTSD symptoms than Veterans who did not have anniversary reactions, and all of the Veterans who met criteria for a diagnosis of PTSD had anniversary reactions (6).
Most people will feel better within a week or two after the anniversary. Over time, the stress symptoms will decrease in both frequency and severity. Providers can suggest strategies to help survivors through the anniversary period. For example, survivors may find it helpful to make specific plans for the anniversary day so that they have other things to occupy their time besides memories of the event. Some may choose to participate in a commemorative ceremony such as visiting a grave, making a charitable donation, giving blood, helping others, or dedicating the day to spending time with family.
It is common for people who did not seek help for the original trauma to feel ashamed that they are still suffering months or years later. However, the fact that someone did not seek help may itself be symptomatic of trauma-related avoidant behaviors and can be viewed as a signal that professional help should be sought.