Is It Anxiety or OI?

Managing CFS, Understanding CFS | 21. Jun, 2011 by | 8 Comments

By K. Kimberly McCleary, President & CEO

The “Outs and Ins of OI” article posted on Sunday generated lots of questions and comments, both here on Research1st and on our Facebook page, where the conversation started. Anne Boyd posed this question about the potential for confusion about the symptoms of anxiety and those of orthostatic intolerance (OI):

“I believe another common problem is that the symptoms of OI can feel *so much* like anxiety that they are probably often written off as *caused* by anxiety. I was once given a an “anxiety scale” to fill out at a psych visit, and many of the items on there were physical symptoms. I searched online, and this looks a lot like the questionnaire I filled out:

Look how many of the items on this scale are physical symptoms! And a lot of them quite consistent with OI, not to mention CFS generally. I certainly have shakiness, weakness, shortness of breath, etc. etc. Some of my worst moments with OI have been standing in lines, such as at the grocery store, and I have pointed out to my doctors that I do NOT have a phobia about cash registers!”


Dr. Peter Rowe

Dr. Peter Rowe,  professor of pediatrics, Johns Hopkins University School of Medicine, kindly provided this information:

“This debate is informed by some very nice work by the group at Vanderbilt University. A publication in the Journal of Neurology, Neurosurgery, and Psychiatry titled, “Psychiatric profile and attention deficits in postural tachycardia syndrome” by V. Raj et al., examines this issue. These pertinent paragraphs from their discussion highlight the importance of looking at a measure that examines anxiety provoking conditions (e.g., the Anxiety Sensitivity Index) in those with CFS and orthostatic intolerance, as compared to one that relies on somatic symptoms (e.g., the Beck Anxiety Index). The somatic symptoms, such as lightheadedness (which appears twice among the 21 symptoms on the Beck list) or heart pounding/racing, would be over-represented among those with orthostatic disorders, even if they were not anxious at all.”

From the paper by Raj et al.:

“Patients with POTS did not experience a significantly increased lifetime prevalence of anxiety disorders (including panic disorder) compared with a general population sample or subjects with ADHD. For current anxiety symptoms, patients with POTS scored significantly higher than controls and ADHD subjects on the BAI, and within the moderate anxiety range. However, when using the cognitively focused ASI, patients with POTS did not score higher than the general population (they actually had a trend towards a lower score) although they still scored higher than control subjects free of axis I psychiatric disorders. This is supported by the findings of Masuki et al who reported that ASI scores in 14 patients with POTS were significantly higher than in control subjects but within the limits of published general population data.


Figure 1 The Beck Anxiety Inventory (BAI) scores (A) and the Anxiety Sensitivity Index (ASI) scores (B) are shown for healthy control subjects (normals), patients with postural tachycardia syndrome (POTS), patients with attention deficit hyperactivity disorder (ADHD), and published population norms (dark grey). Differences between the two anxiety tools may reflect inclusion of somatic anxiety symptoms in the BAI whereas the ASI scores only for cognitive anxiety.

“The contrast between the BAI score (moderate anxiety) and the ASI score (comparable with the general population) in the POTS group is striking. A major difference between the BAI and ASI is that the former measures both somatic symptoms and subjective anxiety and panic symptoms on factor analysis while the latter measures sensitivity to anxiety provoking stimuli but not somatic symptoms. Since the orthostatic symptoms experienced by patients with POTS are similar to the somatic criteria required for the diagnosis of panic attacks or other anxiety disorders (eg, palpitations), it is likely that these symptoms, rather than psychological factors, elevate the BAI scores. Unlike subjects with panic disorder, patients with POTS show several important clinical differences that can be used to distinguish between the two disorders. These include predictable precipitants for the onset of somatic symptoms in subjects with POTS (eg, dehydration and standing) while patients with panic disorder experience repeated episodes without a clear precipitant. Furthermore, patients with POTS experience a significant worsening of somatic symptoms on adoption of the upright position while subjects with panic disorder typically do not. It is therefore likely that the somatic symptoms in POTS patients do not represent panic disorder, which is appropriately reflected in the lower ASI score. This finding is supported by two recent studies. Masuki et al showed that excessive increase in heart rate in patients with POTS in response to orthostatic stress is not caused by anxiety.  Khurana collected data on anxiety and somatic symptoms in response to anxiety provoking stimuli and found that symptoms of POTS were distinguishable from symptoms of panic disorder. Taken together, the evidence suggests that clinically observed anxiety in patients with POTS is caused by biological rather than psychological factors.

“As POTS progresses, there is a significant decrease in ASI score but no significant change in BAI score. This suggests that there is a diminution in cognitive anxiety symptoms with time, but not in somatic symptoms. Our data suggest that patients with POTS experience inattention of a magnitude that is greater than in controls but less severe than in adult ADHD subjects. Unlike ADHD subjects, patients with POTS did not report more inattention during childhood. This could indicate a causal role for POTS in attention difficulties, or suggest that the two problems share common antecedents. Moreover, this might suggest common genetic underpinnings as noradrenergic gene products regulate sympathetic tone, cardiac output and attention. Interestingly, there is a significant perceived reduction in the magnitude of inattention and ADHD symptoms as POTS progresses. This could reflect patient adaptations or an improvement in POTS symptoms over time.”

As the article by Raj et al., reflects, there are different instruments used in research and clinical settings to evaluate anxiety and panic disorders. The Beck Anxiety Index, the Anxiety Sensitivity Index and Zung Self-Rating Anxiety Scale (mentioned by Anne in her question) are just three of those instruments. For instance, on the Beck Anxiety Index, 21 symptoms are listed and 9 of them specifically overlap with symptoms of orthostatic intolerance: feeling hot, wobbliness in legs, dizzy or lightheaded, heart pounding/racing, unsteady, shaky/unsteady, difficulty in breathing, faint/lightheaded, hot/cold sweats. The Beck uses as 0-3 rating scale, with 0 being “not at all” and 3 being “severely — it bothered me a lot.” The cut-offs for measuring mild-moderate-severe anxiety appear to differ. The Beck specifically inquires about an individual’s symptoms in the past month; other instruments use different time periods for assessment. For instance, the Zung inquires about the “past several days.”

We hope this information answers Anne’s question, as well as provides research-supported data to share with health care professionals who may be unaware of the important distinctions between two conditions that may superficially appear to share common symptoms. Thanks to Anne and others who have contributed to this dialogue.

K. Kimberly McCleary has served as the Association’s chief staff executive since 1991.


Raj V, Haman KL, Raj SR, Byrne D, Blakely RD, Biaggioni I, Robertson D, Shelton RC. “Psychiatric profile and attention deficits in postural tachycardia syndrome.” Journal of Neurology, Neurosurgery and Psychiatry. 2009;80;339-344.

June 21, 2011