Biology 1 Report: Critical Appraisal of Yoga Study on Women

This report provides a critical appraisal of a study investigating the effects of yoga on depression and anxiety symptoms in women attending a yoga health center. The research employed a quasi-experimental design, assessing participants using the Beck Depression Inventory (BDI) and the State-Tra...Read More

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Abstract
Yoga has been proposed to be an effective intervention in treating depression and anxiety
symptoms. The research was aimed at assessing the impact of yoga in treating symptoms of
depression and anxiety among women attending a yoga health center. To accomplish the
objective of the study, a sample of women who had been recommended to a yoga health center
for one year were conveniently sampled and assessed on admission using a personal
questionnaire form. The women had to be free from any previous psychological illness and were
not advised to take yoga by any physician. The potential participants were assigned to the
experimental and control group. The authors found out the experimental group had an
insignificant decrease (p=0.13) in the incidence of depression. On the other hand, there was a
significant decrease in the symptoms of state and trait anxiety with p values of p=0.03 and p<
0.001 respectively. The average depressive score in the experimental group was
12.82 and 10.79 before and after intervention respectively. Cases of
depression in pre- and post-treatment were 44.1% and 32.3% respectively.
Average state anxiety before and after intervention was 2.29 and 1.85
respectively. There were 65.3% cases of trait anxiety and 20.6% in pre and
post treatment respectively. Therefore, the findings show that yoga can be used as an
effective optional treatment for normal treatment in treating anxiety disorders.
Measurement
All cases were measured using the Beck Depression Inventory (BDI) and the State-Trait Anxiety
Inventory tests. The BDI contains 21 items used to evaluate the extent of depression. BDI is the
most commonly used and reliable questionnaire for determining and evaluating the intensity of
depression in a normal population. The tool evaluates any symptoms of depression in an

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individual in the preceding week and measures the degree of depression on a scale ranging from
0 to 3 out of a total of 0 to 63. Higher scores are an indication of high depression. For instance, a
score of 0-9 designates no depression; 10-18 shows evidence of depression; 19-29 indicated
average depression, and 30-63, acute depression. This questionnaire measures three symptoms of
depression namely cognitive, affective and somatic.
The bifactor model of the BDI allows the summing up of all BDI items to an overall score.
Higher overall scores are a better way of showing the severity of depression. Additionally, the
three specific factors minimize the number of variances that are found in the BDI items, thus
improving the validity of the subscales. This further improves the validity of the instrument
because both the BDI total scores and the subscale scores can be used to determine the intensity
of depression.
Since the use of BDI global score only as a measure to ascertain variations in response to
interventions is likely to lessen the effect of treatments, its combination with the subscale scores
makes the tool more appropriate both for clinical and statistical reasons. Moreover, depressive
symptoms have varying responses to treatments, thus requiring more than one scale of
measurement. The BDI has a high internal consistency due to the high reliability of the total and
subscale scores. The BDI scores have also the ability to differentiate between individuals from
the healthcare centre and the general population thus making it have a high degree of sensitivity
to change.
The Spielberger questionnaire or the State-Trait anxiety inventory (STAI) is another commonly
used method for evaluating symptoms of anxiety and it contains equal items for trait and state
anxiety. The trait anxiety offers information regarding the current D of an individual, and the
symptoms of stressful circumstances are likely to be observed as variations in trait anxiety. The

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use of the trait anxiety scale is dependable in the clinical setting in distinguishing between
individuals at risk of anxiety. Such a distinction is important during counselling because the
anxiety trait can give an indicator of variations in anxiety that may be due to therapy.
The use of STAI was appropriate for the study because it has a good discriminating ability for
both high and low scoring scores. The reliability coefficients of the inventory are an indication
that it is an appropriate tool for research and in clinical settings. The STAI is also a valid
measure in differentiating between temporal and permanent anxiety. Moreover, it reflects the
distinctions between seemingly stressful and non-stressful circumstances and at the same time
producing a valid and reliable measure of one’s anxiety level. Furthermore, it is an important
device in measuring the variations in the anxiety of individuals during therapy sessions.
Potential Threats to Internal and External Validity
Internal validity
Being experimental research, the study had multiple potential threats to internal and external
validity. Some of the potential threats to the internal validity of the study include subject
characteristics, instrumentation, and mortality. The participants both in the control and
experimental groups were selected at different times and assessed over two months. It is
therefore likely that there might exist subject differences in the results between the two groups
that are associated with the varying variables under consideration. Such a difference might lead
to selection bias which means that some unique characteristics in the subjects might result in
favours.
Instrumentation is another threat to internal validity. This implies how instruments are used in
the research, which is likely to become a threat to internal validity. This usually occurs based on
how the instruments are utilized in the study. The study used two common instruments namely

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Beck and Spielberger inventory tests. The procedure of administering the device is likely to vary
with other experts over the two months thus leading to instrument decay. Such changes can cause
significant changes to the outcomes of the observation. Instrument decay may also be caused by
fatigue of the one administering the tool. The use of the two instruments in measuring depression
and anxiety might be tiresome and thus making the observer miss some measurements that are
critical for the research. Instrumentation can also be threatened by the attitude of the participants
towards the instruments being used for measure. For instance, the researchers used both Beck
and Spielberger inventory tests on each participant to ascertain the presence and intensity of
either depression or anxiety or both. Moreover, these tests have a total of over forty questions,
and this is likely to cause fatigue to the discussants. Such an attitude towards the instruments
may cause them to decline in taking additional tests thus causing the results to be biased.
Since the study involved human beings, there is a possibility that some of the participants
withdrew from the study while it was underway. This is a threat to internal validity. The loss of
subjects in a study is referred to as mortality, and such a loss can limit the generalizability of the
study and is likely to lead to bias. This is because the subjects that may have withdrawn may
often not be similar to those that remained in the experimental or control group. The findings
also indicate that there was a positive effect of instruments of measure on the participants, and
therefore any withdrawal during the study is likely to affect the conclusions of the study, thus
compromising even the effectiveness of the instruments.
External validity
There exist multiple potential threats to the external validity of the study. An example is a
multiple-treatment interference in which the participants are administered more than one

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treatment and may result in an interaction of the effects of multiple treatments. The study
involved the measure of both depression and anxiety symptoms using two instruments namely
Beck and Spielberger inventory tests. The effects of such multiple treatments may likely interact
causing a threat to external validity. Another threat is the selection-treatment interaction in which
there is the possibility that some of the characteristics of the subjects selected for the research
interact with some of the elements of the treatment. These can include previous experiences,
character, temperaments, or learning that might interact with the effect of the treatment. There is
a possibility that the participants were aware of the measurements or had experienced them
before thus causing an interaction with some aspects of the treatment.
Recommendations for Avoiding the threats to Internal and External Validity
The above-discussed threats to internal and external validity can, however, be avoided or
minimized. The threat of subject characteristics can be avoided by using an inclusion and
exclusion criteria to avoid selection bias which results from having favours to superior subject
characteristics. The threat to mortality can be reduced by ensuring that the researchers gather
detailed information about the potential participants of the group, their involvement, and how
they will participate to the end of the program. This will be critical in explaining any attrition
that may take place during the intervention. The threat of instrumentation can be avoided through
careful specification and management of the measurement procedures such as the use of
standardized instruments. Multiple-treatment interference can be avoided by selecting a design
with minimal treatments assigned to each participant. Selection-treatment interaction can also be
avoided by random selection of the participants.