A qualitative study comparing 30 minutes of cycling at moderate heart rate against a mono-therapy Selective Serotonin Reuptake Inhibitor (SSRI) in the treatment of mild depression.
Introduction
For the purpose of this essay the author will write in the first person (Hammil 1999).
This essay will examine the literature relating to physical exercise and its affect in treating depression. Following this I will form a research proposal to examine the effect of cycling for 30 minutes at a maximum estimated heart rate of between 65% to 75%, moderate intensity and compare this to the effect of taking an SSRI at the lowest recommended therapeutic dose using British National Formulary (Royal Pharmaceutical Society 2013) as a guide to recommended dose, in relation to improving mood in people with an ICD 10 (WHO 1999) diagnosis of mild depression.
There has in recent times been links made between physical and mental health and this has been addressed to some degree in the UK Government document ‘No Health without Mental Health’ (DOH 2011). One in four people in the UK experience mental health problems in the course of a year, depression being the most common disorder in the UK (Mental Health Foundation 2013). Almost 50 million people were prescribed antidepressants in 2011 with a cost of £270 million. This has a massive implication on a financially restricted National Health Service. Dean and Jamieson (2006) suggest that exercise is a low cost intervention which has the potential, if effective, to play a significant role in both developing and developed countries in the treatment of depression. This proposal will focus on the use of exercise as a cost effective alternative to antidepressant therapy for people with mild depression.
Literature Review
Material for this literature review was drawn from searches conducted on AMED, MEDLINE, PsychINFO, CINAHL and Cochrane Library. I have used PICO and SPICE models as described by Gerrish and Lacey (2010) to complete a literature search. To assist this search each element of the models was searched separately then each search statement was combined using Boolean operators. Boolean operators are ‘AND’, ‘OR’ and ‘NOT’, (Gerrish & Lacey). Polit and Beck (2010) guidelines have been used to assist me to compare, contrast and critique the literature in a structured and systematic way.
On reviewing the literature no papers were found which directly compared physical exercise against antidepressant therapy. A number of papers with reoccurring themes did emerge. These themes were the use of physical activity in treating depression. The literature would appear to be conclusive that physical activity can have a beneficial effect on mood. They compare varying levels of activity intensity and tools to measure what constitutes specific intensities of exercise, the validity and reliability of which does not always appear robust. For the purpose of this proposal I will only focus on a limited number of these papers which while widely different in approach are closely linked to this research proposal as they explore the use of exercise in the treatment of depression. The reason for the limited number of studies in this review is that there are too many studies too critically discuss in depth. The two studies I will review are, ‘Exploring the effectiveness of an integrated ‘exercise/CBT interventions for young men’s mental health’ (McGale et al 2011) and ‘Walk on the Bright Side: Physical Activity and Affect in Major Depressive Disorder’ (Mata et al 2011).
The study by McGale et al (2011) is a pilot study investigating the effectiveness of a team based sport/psychosocial intervention with an individual exercise and a control condition for the mental health of young men. The design of the study was for a ten week randomised control trial and eight week post intervention follow up. The eight week follow up does raise some questions in terms of reliability what conclusions can be drawn from the Beck Depression Inventory-2nd edition (BDI-ii) (Beck, Steer and Brown 1996) and the Social Provision Scale (SPS) (Caron and Russel 1987). This is an attempt to mix quantitative data from the BDI-ii (Beck et al 1996) and qualitative data from the SPS (Caron and Russel 1987), however no account is taken regarding possible events which may have occurred between the conclusion of therapy and the post intervention follow up. Emotionally traumatic events may have worsened mood during this period or the participants may have become physically unwell or sustained an injury which may have lessened or even prevented physical activity at the prescribed levels. The eight week follow up does not appear to measure physical activity during the post intervention stage, only measuring mood outcome.
The Method uses 104 sedentary males aged between 18 and 40 years. While it could be argued that the number of participants in the study is of a large enough number to be significant for a pilot study, the eventual up take of participants was only 85, 81% of the initial study numbers. While this is not a significant drop out rate it does reduce the overall participant numbers substantially and as the initial numbers were already limited it may have an effect on outcome data. There are also some questions raised by the limit of gender age and activity level. The study is exclusive to males only and this it could be suggested that this will limit the transferability of the study in term of possible treatments that could be developed for the general population. It is recognised that males respond slightly better to CBT interventions and this may be the reason for the exclusion of females from the study, however this could be seen as being a negative with regard to the reliability of the study. As this is a pilot study it could be suggested that further studies may be considered which do not exclude by gender including male, female and transgender participants to maintain validity and reliability of future studies and the possible implementation of findings.
There is also a degree of difficulty with regard to transferability of findings in that the study has limited the study group to participants who are assessed as sedentary prior to the study. This may exclude the effect of increasing activity for those who are already mildly physically active and who sit outside of the sedentary group. The question may be asked, would this group also respond to an increase in activity again further research may be beneficial by including participants with a higher pre-study activity level so that the findings are not limited to those who were previously sedentary.
Though the study concludes a 52% improvement in mood following the interventions, the study design of using physical activity and CBT in tandem causes difficulty in meaningfully interpreting these results as one cannot differentiate between which of the interventions have had an effect on the study outcome. This is recognised by the study which recommends that larger studies using only one intervention be used.
The study by Mata et al (2011), examined the effect of self-initiated physical activity on negative affect (NA) and Positive Affect (PA). The study used a sample of 38 female and 15 male taking part in the study. Participants were given a palm pilot and this was used to randomly prompt participants to give feedback regarding physical activity eight times daily between 10am and 10pm. Participants were asked to answer questions based on NA, PA and activity level. The level of activity intensity was calculated by the type of activity with activities such as walking being rated as mild levels of activity, other activities such as swimming as moderate and more strenuous activities such as running high level. It could be argued that this is an inaccurate tool for measurement of activity intensity as it only takes in to account perceived intensity of the participant. The use of heart rate or wattage output is ignored. It could be suggested that this may result in perceived levels of activity varying widely as individual fitness may differ as may an individual’s perception of intensity level. The problem of misinterpretation of perceived intensity may be more pronounced in those suffering from depression, Hawton et al (1989) suggests that people with depressed mood experience cognitive distortion or negative automatic thoughts which negatively alter their perception of events This may result in the study giving an inaccurate account of which levels of activity intensity best provide a positive effect of NA and PA.
The study found there to be an increase in PA in participants who had an increase in activity compared to those whose activity did not increase but no change in levels of NA between the study groups. Unfortunately it is not possible to conclusively draw a conclusion with regard to the level of activity required for this effect to occur as previously mentioned activity levels were quite subjective in how they were measured.
As the study was designed to examine NA and PA there is no findings which address mood overall. This is unfortunate as The World Health Organisation (1989) suggest that affect is only one of a variety of symptoms effecting mood.
The study took place over a 7 day period, though this may give a snap shot of activity it could be suggested that this is a very limited period for the study to examine activity levels, to associate these levels of activity over only 7 days with participants affect appears somewhat limited at best as activity may differ considerably on a week to week or month to month period. This could raise question marks with regard to the reliability of the study’s findings.
Summary
Both studies in this literature review draw a link between levels of physical activity and improvement in symptoms of depression. While McGale et al (2011) used externally validated heart rate monitors to rate activity level aiming for participants to exercise at a level indicating moderate intensity of activity, the study by Mata et al (2011) used a much less structured measurement depending on the type of activity and perception of the participant to measure intensity. The use of heat rate appears to be more measurable and far move valid as it can be replicated and is not open to misinterpretation. However the participant’s interpretation of activity may have as valid an effect on mood as physical level exertion though this may require a more qualitative approach to achieve findings.
The Study by McGale et al (2011) examined two interventions that of CBT and exercise while Mata et al (2011) examined only physical activity. While there are questions asked of Mata et al (2011) data with regard to intensity of activity the findings clearly link intensity and regularity of physical activity as an effective intervention. While the data from McGale et al (2011) cannot distinguish between either CBT or Physical Activity as the trigger for improved mood it would appear that physical activity has had a role to play in the results. McGale et al (2011) does go on to identify the limiting nature of the study and recommends further individual therapy studies take place. Both studies had small participant groups though McGale et al (2011) recognises this in the study and recommends larger individual interventions take place. In comparison the study by McGale et al (2011) is more relevant in its method and methodology to this research proposal though Mata et al (2011) is not without its positives influences on this proposal.
Methodology
This research proposal aims to compare the use of physical activity at a moderate level occurring three times per week at set days against the use of a mono-therapy Selective Serotonin Reuptake Inhibitor in the treatment of mild depression with both interventions initiated at the same time and lasting over a twelve week period.
A quantitative approach will be utilised in the form of valid measuring tools. I feel this approach is suitable as quantitative research provides a method of achieving rigorous and systematic evaluation of practice (Jack and Charles 1998). It is suggested by Brink and Wood (1998) that external validity is a major concern in quantitative studies and describe representativeness as an issue to whether the sample studied can be generalised to a larger population (Polit and Beck 2010). This proposal has endeavoured to address this by giving consideration to this area.
Method
Sample
The Sample for this study will be taken from 5 mental health assessment teams and 4 hospital liaison teams from a large mental health trust which covers both inner city areas which include areas of social depravation and more affluent suburban areas. As large a catchment area as possible has been used for this study as Bowling (2009) suggests that it is important to do this in order to ascertain the amount of natural variation between areas and to ensure the external validity of the results. 100 participants will be recruited using starfield random sampling (Polit and Beck 2010) from a pool of participants identified as having a first episode mild depression using the ICD 10 (WHO 2010) to identify diagnosis. A sample frame will be used (Parahoo 2006) to randomly pick participants for each group to control possible extraneous variables allowing robustness by reducing bias in the study.
Participants will be split in to two groups, group A will take part in 30 minutes exercise on each Monday, Wednesday and Friday exercising at a heart rate indicated intensity level of moderate exercise. This will be on static cycles with an additional 5 minute warm up and 5 minute cool down. The choice of static cycles is to reduce the possibility of injury as this is a low impact non-weight bearing activity.
Group B will receive minimum therapeutic dose of an SSRI antidepressant as indicated by the British National Formulary (Royal Pharmaceutical Society 2013), they will be asked not to increase their activity level during the study.