Friday, January 8, 2010

How does cognitive behaviour therapy reduce fatigue?

Another great analysis by Tom Kindlon!
How does cognitive behaviour therapy reduce
fatigue in patients with chronic fatigue syndrome? The role of physical

The pedometer data and a few extracts:

The three studies were:
Knoop H, van der Meer JW, Bleijenberg G (2008). Guided
self-instructions for people with chronic fatigue syndrome: randomised
controlled trial. British Journal of Psychiatry 193, 340-341.

Stulemeijer M, de Jong LW, Fiselier TJ, Hoogveld SW, Bleijenberg G
(2005). Cognitive behaviour therapy for adolescents with chronic
fatigue syndrome: randomised controlled trial. British Medical Journal
330. Published online : 7 December 2004. doi

Prins JB, Bleijenberg G, Bazelmans E, Elving LD, de Boo TM,
Severens JL, van der Wilt GJ, Spinhoven P, van der Meer JW (2001).
Cognitive behaviour therapy for chronic fatigue syndrome: a
multicentre randomised controlled trial. Lancet 357, 841-847.


The approaches were all based on CBT manual:
"Treatment was based on the manual of CBT for
CFS described in detail by Bleijenberg et al. (2003)
and effectively reduced fatigue severity in all trials."

Bleijenberg G, Prins JB, Bazelmans E (2003). Cognitivebehavioral
therapies. In Handbook of Chronic Fatigue
Syndrome (ed. L. A. Jason, P. A. Fennell and R. R. Taylor),
pp. 493-526. Wiley: New York.


Table 2. Baseline, second assessment and change scores on fatigue
severity and physical activity in the group of included patients per
treatment condition

Prins et al. (2001) (n=211)
Treatment condition . CBT Control
(n=70) (n=141)

Fatigue severity:

52.4 (4.0) 51.7 (4.1)

Second assessment
40.3 (10.5) 45.8 (8.7)

Change score
-12.1 (10.3) -6.0 (9.2)

Physical activity:

67.4 (21.8) 64.5 (19.7)

Second assessment
68.8 (25.2) 64.9 (21.7)

Change score
1.4 (18.5) 0.4 (16.4)

Knoop et al. (2008) (n=132)
CBT Control
(n=58) (n=74)

Fatigue severity:

49.5 (5.1) 49.6 (5.7)

Second assessment
38.9 (10.8) 45.7 (8.9)

Change score
-10.6 (11.1) -3.9 (8.4)

Physical activity:

63.1 (23.5) 63.5 (21.8)

Second assessment
67.3 (22.5) 67.8 (21.4)

Change score
4.3 (20.4) 4.3 (21.0)


Stulemeijer et al. (2005) (n=58)

CBT Control
(n=28) (n=30)

Fatigue severity:

52.3 (4.1) 51.3 (4.4)

Second assessment
24.8 (14.1) 42.9 (13.9)

Change score
-27.5 (14.2) -8.4 (13.4)

Physical activity:

65.6 (22.4) 65.0 (20.1)

Second assessment
75.8 (21.7) 67.7 (23.8)

Change score
10.3 (21.7) 2.7 (28.1)

CBT, Cognitive behaviour therapy.
Values are given as mean (standard deviation).

Information on the outcome measures/instruments:


The subscale fatigue severity of the Checklist Individual
Strength (CIS) was used to indicate the severity
of fatigue experienced by patients. It consists
of eight items which are scored on a seven-point
Likert scale. The sum score varies between 8, no fatigue,
and 56, severe fatigue. The CIS is a reliable and
valid instrument for the assessment of fatigue in CFS
(Vercoulen et al. 1994; Dittner et al. 2004). A common
cut-off score for severe fatigue is 35 (or higher), which
is about two standard deviations above the norm score
for healthy patients.

Physical activity

Actigraphy was used to assess physical activity in all
trials. The Actometer is a motion-sensing device
which is worn around the ankle for 12 consecutive
days. An average daily level of physical activity is
computed over this period, with higher scores indicating
more physical activity. The Actometer is described
in more detail by van der Werf et al. (2000).
They found a significant difference between the mean
Actometer score of CFS patients which was 66 (S.D.=
22) and healthy controls who had a mean Actometer
score of 91 (S.D.=25).
They also identified a group of
patients who scored below the mean score of CFS
patients on 11 out of 12 days and labelled this group
as pervasively passive. We excluded all patients from
our study who missed actigraphy at second assessment."

[TK: My guess is the Actometer score for healthy adolescents (relevant
for Stulemeijer et al. (2005) study) would be higher than 91 (25)m
which was calculated from adult controls as I recall]

The data did not support a treatment model in which
the effect of CBT on fatigue is mediated by an increase
in physical activity. CBT did neither cause an increase
in physical activity at the end of treatment (path a) nor
was an increase in physical activity associated with a
reduction in fatigue (path b).
A formal test of the mediation
effect confirmed that CBT yielded its effect independent
of a persistent change in physical activity.

These results are in line with the study of Moss-
Morris et al. (2005) in which it was demonstrated that
not an increase in fitness but a change in preoccupation
with symptoms mediated the effect of GET on
fatigue. The results are also consistent with earlier research
on CBT for CFS in which a reduction in fatigue
was associated with a change in illness beliefs (Deale
et al.1998). In the light of these findings, changing illness-
related cognitions seems to play a more crucial
role in CBT for CFS than an increase in physical activity.

[TK: My chief observation is most people would believe that actometer data
is more objective than outcome measures from questionnaires like fatigue
scores.  And as they shown, CBT wasn't increasing activity levels.  These
studies reported improvements in the SF-36 physical functioning subscale,
while again many people might be more impressed by improvements in actual
physical functioning (as measure by a pedometer) not a change in how people
respond to questionnaires!]

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