The Effectiveness of Cognitive Behavioural Therapy (cbt) for Treating Individuals with Depression and Anxiety

Within this literature review, literature that focuses on the effectiveness of Cognitive Behavioural Therapy (CBT) as treatment for depression and anxiety will be reviewed and valued. Firstly, it is important that CBT is defined and understood as a “structured, goal directed and collaborative intervention strategy” (Clark, 2014 cited by Mothersill, 2016) to work towards exploring and understanding an individual’s psychological disturbances (Mothersill, 2016). This is important as it should be recognised individually to other methods of therapy in counselling. Also it is important that when assessing the effectiveness of CBT that you are specific in what you are hoping to achieve through the use of this therapy. For example, CBT may treat a certain disorder but not another. This means it is important to specify what you want CBT to treat. Within this literature review research into CBT’s effectiveness in treating depression and anxiety will be critically reviewed.

Many forms of research use self-assessment as its experimental design, this can be seen as a strength or weakness. A weakness of research that use self-assessment is that people may not respond truthfully and therefore the results would become invalid, also this can affect the establishment of cause and effect within the research. For example, Norell- Clarke et al (2015) researched the effectiveness of CBT and relaxation training (RT) on participants with depression. Norell- Clarke et al (2015) had 64 participants whom they had recruited by advertisement to receive CBT or RT to help treat their insomnia and depression, as the two diagnosis are closely linked. Norell- Clarke et al (2015) then assessed their participants using the insomnia severity index and the BDI-11, pre- treatment, post- treatment and at a six month follow up self-assessments. They also asked the participants to keep a sleep diary a week prior to treatment and for the duration of treatment. Norell- Clarke et al (2015) found that CBT was more effective in treating insomnia and depression than RT. However, CBT did have a higher readmission rate than RT. Norell- Clarke et al (2015) completely rely on self- assessment methods to confirm their findings, therefore, the results may be biased and invalid, as the participants may fabricated their responses. Norell- Clarke et al. (2015) should have used a more reliable method of collecting data to improve the credibility of their research. Therefore, this literature is not very useful in predicting the effectiveness of CBT as a treatment of depression.

In contrast, self-assessment can be a useful method of data collection. This is because self-assessment enables the researchers to examine a large number of variables and can ask participants to reveal information about their behaviour in a specific real situation. As well as this self-assessment is a much cheaper way of collecting data than many other methods. Anderson, Watson and Davidson (2008), assessed whether the use of CBT was effective in reducing anxiety symptoms in a hospital. They collected data from structured interviews with the patients and analysed pre intervention and post intervention anxiety and depression scores. Anderson, Watson and Davidson (2008) concluded that CBT was effective in hospitals for patients with mild to moderate anxiety or depression. The use of self-assessment enabled Anderson, Watson and Davidson (2008) to draw this conclusion. Also with the use of self-assessment, if the participant pool is selected at random and large enough it is possible to generalise the results of the finding, which increases the value of this research. Anderson, Watson and Davidson’s (2008) research can therefore be considered a beneficial piece of literature researching the effectiveness of CBT as a treatment of anxiety and depression.

Another strength of literature that assesses the effectiveness of CBT to treat depression and anxiety, is if the researchers use meta-analyses. This is a strength as it draws together multiple research in order to create a larger participant pool and enable precision. Research conducted by Twomey, O’Reilly and Byrne (2014) used a meta-analysis focusing on CBT and randomised controlled trials to assess the effect CBT has on the relief of symptoms of anxiety and depression. Twomey, O’Reilly and Byrne (2014) reviewed 29 randomised controlled trials and found that multi-modal CBT is effective in reliving the symptoms of anxiety and depression, within a primary care situation. The use of such a large amount of research means that a more definite conclusion can be met, often results of individual research is inconclusive and meta-analysis enable the removal of that issue.

On the other hand, the use of meta analyses can be considered as a major problem as it simply uses other people’s research and re-analyses it to determine results. The research that is analysed may be biased and unreliable. An example of an article that uses meta-analysis and is a systematic review is Bird et al’s (2010) article that looked at previous research to find the effectiveness of early intervention and CBT on early psychosis such as depressive psychosis. Bird et al (2010) did a systematic review and meta- analysis on randomised controlled trials. They found that CBT was useful to reduce symptom severity however didn’t prevent hospital admission or reduction in relapse rates. Although this may seem a useful discovery, there is no certainty that the research Bird et al (2010) assessed is valid and therefore may mean that Bird et al’s (2010) literature does not measure what it was originally meant to.

A strength however, of literature research into the effectiveness of CBT as a treatment for depression and anxiety is the fact researchers in this field often perform follow up assessments. Follow up assessments are beneficial to research as they allow the researcher to see if CBT has been effective in the long term, not just immediately after the participants have received the therapy. If the researcher can see that CBT is effective in the long term it is worth investing money in future use of the therapy. An example of research that consistently follows up the participant’s depression and anxiety with Parkinson’s disease is Troeung, Egan and Gasson (2014). This research had a participant pool of 18 adults suffering with Parkinson’s disease, depression and/ or anxiety. The participants were randomly assigned to the eight week CBT intervention or the waiting list. Troeung, Egan and Gasson (2014) then followed up the progress of the CBT at pre- treatment, post- treatment, one month and six months’ post treatment. This is useful in research as they can tell if the adults found CBT beneficial they also had a control group that they could use to compare the effectiveness of CBT for this type of mental health disorder. The use of follow up assessments enhances the value of research into the efficiency of CBT as a treatment of depression and anxiety.

A weakness of literature assessing the effectiveness of CBT as a treatment of anxiety and depression, on the other hand, is that much research struggles to find a sufficient sample size. This is because the requirements of the participants are rather specific, which limits the individuals’ that researchers can use in their experiments. Urao et al. (2016), conducted a quasi-experiment in Japan, that had an anxiety CBT intervention group consisting of thirteen participants, who were recruited using poster advertisements and a sixteen participant control group. Within the research child and parent reported anxiety symptoms within the Spence Children’s Anxiety Scale. Urao et al. (2016) found that CBT was partially effective from the parent’s evaluation. The use of 29 participants is an extremely small sample size and means that the researchers were unable to generalise their results to all children in Japan. A small sample size may also be the reason that the results of the research were relatively inconclusive, claiming CBT was only ‘partially’ effective. Therefore, the use of a small participant pool poorly effects the usefulness of the research into the effectiveness of research into CBT as a treatment of anxiety and depression.

Literature that assesses the effectiveness of CBT as a treatment of anxiety and depression are extremely specific in the participant selection process. This is beneficial to the validity of the research as it means that the findings and conclusions can be more easily generalised to the whole population of that specific group. For example, Chorpita et al. (2004) selected eleven participants, all had to be between the ages of seven and seventeen, all had been referred for CBT at the University of Hawaii, all must have a DSM diagnosis of anxiety. The specific needs of this researches participants mean that in general they are all experiencing the same situations i.e. School, homework learning new skills etc. this means that the researchers were more easily able to generalise the findings to seven to seventeen year olds. Chorpita et al. (2004) found that at the post CBT assessment all children were absent from symptoms of anxiety, this was the same for the six-month follow-up assessment. Therefore, Chorpita et al. (2004) concluded that “there is initial support for the use of… CBT for anxiety disorders in youth” this ability to generalise to “youth” is only possible due to the restricted sample while eleven individuals from all ages would not have been so generalizable. This benefits the research literature into the efficiency of CBT as a treatment of anxiety and depression.

Much of the research that has been conducted in this field does not give any recognition to any confounding and extraneous variables. Extraneous variables can have a considerable effect on the results collected and therefore should be controlled. For example, Scott (1992) took eight in patients who met the diagnostic criteria for depression and prescribed them CBT for twelve weeks. Every three weeks Scott (1992) measured the patients using the Hamilton Rating Scale for Depression, Beck’s Depression Inventory, Mood Self-Rating and the Nurse’s Observation Scale for in Patient Evaluation. Scott (1992) found statistically significant evidence for the reduction in depression, however, much of the symptoms and morbid thoughts continued. Scott (1992) did not consider any extraneous variables that may affect the extent that patients were treated for their depression, this may be why the research had no specific conclusion and did not benefit the research. For example, the participant may have received bad news or had something upset them to further trigger their depression which may be why it seemed as though CBT did not work. However, Scott (1992) did not consider or control the extraneous variables and therefore this research is not very advantageous to discovering the effectiveness of CBT as a treatment for depression and anxiety.

In addition to the aforementioned strengths of literature that researches the effectiveness of CBT as a treatment for anxiety and depression is the fact that research often uses quantitative data. This is useful within research investigating the effectiveness as it is not looking for cause and effect and therefore does not essentially require qualitative data. The use of quantitative data enables objectivity throughout the literature and ensures that no human bias effects the results. Barrowclough et al. () had 43 participants and measured their CBT outcomes using quantitative data collection methods, the Hamilton Rating Scale for Anxiety and the Beck Depression Inventory were amongst the measures they used. Both measures are used to quantify the amount of depression or anxiety a participant was experiencing. Quantitative data enables the researchers to apply statistical tests to draw upon factual conclusions. This is a benefit of literature that investigates the effectiveness of CBT as a treatment of anxiety or depression.

And finally, a major weakness in the design of almost all literature that assesses the efficiency of CBT as a treatment of anxiety and depression, is that most academics do not ensure that the delivery of CBT technique is correct and consistent through-out all sessions and with each participant. Within Hudson et al’s (2015) research the effects of CBT on children with anxiety disorders was studied. In the research 664 child participants who were six to eighteen years of age were telephone screened to ensure they were suitable, given at least eight CBT sessions and then completed post treatment and follow up assessments. Hudson et al. (2015) concluded that CBT resulted in a slow rate of change and “poorer diagnostic outcomes at post treatment” than other treatments. The reason for this may be the diversity that can occur between CBT sessions and the lack of monitoring from the researchers that the CBT sessions were consistent. This is possibly the most significant flaw in the literature that assesses the effectiveness as a treatment for anxiety and depression, as it effects the results so extensively.

In conclusion, although there is a lot of research into the effectiveness of CBT as a treatment of depression and anxiety, much of it, aside from meta analyses, is inconclusive or has factors that majorly decrease the literatures value. The lack of participants in many studies is a huge weakness, as it limits the ability of the research to be generalised. Therefore, it is not as useful as it could be, in determining whether CBT is an effective treatment of anxiety and depression. However, the determining factor of the usefulness of literature that investigates effectiveness of CBT, as a treatment of anxiety and depression is whether or not the researchers regulate the CBT sessions to ensure everyone receives the same treatment. Consequently, many of the strengths of the research into this field are not enough to balance or exceed the weight of the weaknesses of literature and although the research does give us a general awareness that CBT can be beneficial for some relief for sufferers of anxiety and depression, we are unaware of the extent to which it can be relied upon, without further research at this point in time.