How can you tell if a treatment works?

Sorry for the delay in writing this post – I had a bit of a break for finals and moving back home, but here I am with something I found interesting during revision: How can you tell if a treatment works?

At first glance, it might seem like this question can be easily answered, but it is not enough to give a group of a patients the treatment, and then see if their symptoms got better. For example, what if they would have got better anyway? Or it was something about the act of talking about their problems which caused them to feel better, not that the specific aspects of that therapy worked? I will now outline the method needed to conclude whether a psychological treatment is effective or not:

Randomised Controlled Trials (RCTS)

These are a type of experiment, known as the ‘gold standard’ for psychological experiments. The main feature is that participants are randomly assigned to different groups, for example, an experimental group, which receives the treatment, and a control group, who do not. Ideally, the patients in the control group are matched to patients in the experimental group e.g. same age, level of education etc. This is so that the effects of these other variables can be minimised, and so any difference in outcome can be attributed to the treatment. The control group is important to show that patients wouldn’t have got better anyway. For example, Mayou et al (2000) studied the effects of debriefing after trauma and found an objective drop in symptoms 3 years later. However, a control group who received no debrief had almost no symptoms 4 months after (see graph below). This shows the importance of a control group who received no intervention.

mayou et al

As well as finding out if a treatment is more beneficial than no treatment, RCTs can also be used to compare the effectiveness of different therapies for a psychological disorder. For example, Clark et al (1994) compared found cognitive therapy was the most effective treatment for panic disorder, compared to exposure therapy, applied relaxation, or imipramine (a drug treatment).


RCTs also include a follow-up some time after treatment, which enables researchers to tell if the treatment can cause long-term benefits. For example, in the Clark et al study shown above, you can see from the diagram that they carried out a follow up one year after treatment, and that patients in the cognitive therapy group still showed the largest reduction in panic symptoms.

RCTs are the method used to compare therapies, and in order to tell whether a treatment is effective, they need to feature:

  • A valid measure of symptoms at pre-treatment and post-treatment e.g. Body Sensations Interpretation Questionnaire (used by Clark et al to assess misinterpretations of body sensations in panic disorder patients).
  • Broad assessment e.g. patient and independent assessor. (Needed because patients have a tendency to report feeling better than they actually are to the person who’s been treating them).
  • Assess significant pre-treatment to post-treatment change.

It is important to tell whether a treatment works, as if it is shown to be effective, it is more likely to secure funding, and be used on patients within the NHS.

Thank you for reading, I’ll be able to get back into a routine with blogging again now my exams are over so check back soon for new posts!


CBT: what is it and how does it work?

Cognitive Behavioural Therapy,  or CBT is one of the most well known types of psychological therapy.. But how does it work, and why is it so effective?

CBT was developed from the 1950’s, and came to prominence in the 1980’s. It was based on form of Behavioural Therapy, usually used to treat people with phobias. This was based on the principles of classical conditioning: that a conditioned stimulus, when paired with an unconditioned stimulus, produces a conditioned response. This is illustrated by the classic Pavlov’s dogs experiment, as shown below:


This process was used a basis for techniques to reduce fear, for example through systematic desentisation – gradually exposing patients to the phobic stimulus in a hierarchy system in order to reduce their fear (e.g. bottom layer of hierarchy: looking at picture of a spider – top layer: holding a spider in your hand). Part of this therapy is to teach the patient to relax during each step, as that prevents anxiety.

CBT builds on the exposure used in behavioural therapy in order to also address the cognitions behind the fear or anxiety. For example, in panic disorder,  patients suffer from recurrent panic attacks which cause intense fear and distress. The cognitive theory of panic disorder (Clark & Wells, 1995) states that panic attacks are brought on by a misinterpretation of physiological symptoms of anxiety such as palpitations or dizziness. The individual interprets these as that they will immediately suffer a physical or mental disaster e.g. a heart attack.

Part of the CBT for patients with panic disorder is exposure – they will go into a crowded place (if this causes panic attacks for them) and record their feelings, in order to discuss with their therapist. However, it has been found that exposure alone is not as effective as if the cognitions which maintain the disorder are not addressed. These are known as safety behaviours (Salkovskis, 1988): for example if a person who has anxiety about crowds and thinks they are going to faint if they are in a crowded place, they might sit down so they don’t faint. The sitting down is the safety behaviour – it prevents people from realising they wouldn’t have fainted from being in a crowd, they think they only reason they didn’t faint was because they took that action. If exposure is paired with strategies to reduce safety behaviours, it is much more effective at reducing panic and anxiety (Salkovskis et al, 1999).

CBT is recommended as the treatment of choice by NICE (the public body which develops treatment guidance for the NHS) for depression and all anxiety disorders – not just panic disorder. In order for it to be effective, Clark et al, 1994 have shown that a ‘cognitive shift’ must occur in patients (a change in their beliefs), or risk of relapse is much higher.


Let me know if you’ve got any questions or would like more posts like this – hope you found it interesting!

Panic Disorder

Panic disorder is a type of anxiety disorder which is characterised by recurring panic attacks. A panic attack is a brief period of intense discomfort and anxiety, and can cause symptoms like breathlessness and palpitations. During a panic attack, the individual will typically have thoughts such as ‘I’m going mad’ or ‘I’m having a heart attack’ and as a result, can avoid situations which they believe cause the attacks, such as exercising or going to crowded place.

It is relatively common with a lifetime prevalence of about 3.5%.

But what actually causes the panic attacks? It has been argued by some researchers (e.g Clark, 1996) that people with panic disorder interpret normal internal physiological changes, such as heart beat slowing down or getting faster, as a sign that something is seriously wrong with them. These individuals are biased to interpret signals as negative, which increases anxiety and leads to panic – something clearly shown by the flow chart below:


An experiment by Rapee et al (1986) shows how a negative bias causes panic. Participants with panic disorder were asked to breathe in a substance of 50% oxygen and 50% carbon dioxide. Half of the participants were given a thorough explanation of the process and any side effects, while the other half were not given this information. They found that the group which were given the information panicked less and had fewer catastrophic thoughts than the group who were not given the information. This therefore provides evidence to suggest that it is the negative interpretation which causes anxiety and panic – if the side effects were attributed to the procedure then this does not occur.

But why is panic disorder so persistent? If the sufferer thinks they are going to have a heart attack every time they have a panic attack, but this doesn’t happen, why don’t they realise that it is extremely unlikely that the event will actually occur?
The answer to this is that the individual engages in ‘safety behaviours’ which prevent them from learning that the situation is not harmful. For example, if they think they are going to have a heart attack, they will sit down and be very still. When the heart attack doesn’t happen, they think that its because of the fact they sat down, not the fact that they were never going to have one anyway – to them it is a ‘near miss’.

Knowing that safety behaviours contribute to the disorder, one of the main steps in treatment is removing them. This allows people to realise that they are not in a harmful situation, and allows for the therapist to help them restructure their negative thoughts into ones that are more realistic.