One of the most prevalent sources of confusion in health information and news is the report of one disease having been found “linked to” another disease. But it’s important to understand that just because there’s a correspondence or a certain frequency of occurrence in the general population, that doesn’t mean that one disease causes the other. The relationship between the two illnesses could simply be associational – in other words, these two conditions sometimes occur together.
The question becomes even more confusing when reports suggest a greater occurrence of one disease in patients diagnosed with another illness. Take, for example, the studies suggesting that post-traumatic stress disorder (or PTSD) is more prevalent in fibromyalgia patients. The study linked to in the previous sentence was conducted by Drs. H. Cohen, L. Neumann, and others at the Ben-Gurion University of the Negev, in Israel.
The findings of this study indicate that a statistically significant portion of the fibromyalgia population studied also had PTSD. From the study’s abstract:
57% of the FM sample had clinically significant levels of PTSD symptoms. The FM patients with PTSD reported significantly greater levels of avoidance, hyperarousal, reexperiencing, anxiety, and depression than did the patients without clinically significant levels of PTSD symptoms. The prevalence of PTSD among the FM patients in this study was significantly higher than in the general population. Women with FM and PTSD reported a greater number of past traumatic events than did their male counterparts.
CONCLUSIONS: The results represent the first comprehensive study applying structured clinical assessment of trauma exposure and PTSD to a group of FM patients. This study shows a significant overlap between FM and PTSD, according to the currently accepted diagnostic criteria for each.
But does that mean that fibromyalgia is “caused by” or somehow “triggered by” PTSD? The study found nothing of the sort, of course, but these findings have been cited in news articles that can present misleading suggestions of some causative connection that hasn’t been proven yet.
Another study from the same institution looked at whether PTSD and fibromyalgia were really the same illness. While they do share some symptoms in common, it is generally thought that fibromyalgia results from actual neurological changes as opposed to some psychological trauma. It could be that in many cases, an initiating physical trauma causes both PTSD and fibromyalgia.
Yet a lazy researcher could well take that association as grounds for concluding that fibromyalgia is “all in your head” — which is clearly not the case. And given that fibromyalgia is too often relegated to some behavioral issue, as opposed to a systemic or neurological malfunction, that’s unfortunate.
It’s important for fibromyalgia patients to educate and inform themselves, but it’s also important to keep an objective view of studies that are reported in the press.