Seasonal Affective Disorder

It’s that time of year – the clocks have gone back, it’s cold, and already getting dark on our commute home. Whilst many people moan about this time of year, for some it can trigger symptoms of low mood and depression.

Seasonal Affective Disorder is defined as “a type of depression that comes and goes in a seasonal pattern.” (NHS Choices). It’s typically worse from December to February, getting better in spring and summer. For SAD to be diagnosed, there has to be clear evidence of worsening symptoms during winter, which can’t be explained by other circumstances (DSM-IV). In addition, there needs to be evidence for part or full remission during the summer months. Symptoms of SAD are similar to those of depression: low motivation and self-esteem, sleep problems, changes in appetite, withdrawing from social interactions and persistent negative thoughts.


Estimates of the prevalence of SAD range from 0 – 9.4% of the population, depending on who is being studied (Magnusson, 2000). One study compared rates of SAD at 4 different latitudes in the USA and found that is was most common in the northern latitudes (Rosen et al, 1990), which would be expected as SAD can be triggered by lower levels of natural light. This study also found higher rates of SAD in females than males (this finding is in line with overall levels of depression between men and women). It is thought to be caused by the lack of sunlight in winter months disrupting our circadian rhythm, which can be described as our internal body clock. This can affect the serotonin system in the brain, which is responsible in part for mood regulation.

There are various different treatment options for SAD, including light therapy, cognitive behavioural therapy, or antidepressants (Lurie et al, 2006). I’ve spoken about CBT before on this blog (see here for more information), so today I’ll just focus on light therapy and antidepressants as treatments for SAD.


Light therapy involves sitting by a specialised lamp, which emits a specified wavelength and brightness of light (at least 2500 lux). It is thought to work by encouraging the brain to produce serotonin – a neurotransmitter which is linked to feeling happy. Sitting by a lamp for 30 minutes to an hour each morning is the recommended ‘dose’ of light ( One meta-analysis has shown that light therapy is as effective as drug therapy in treating SAD (Golden et al, 2005).

Some antidepressants also work by increasing our serotonin levels. Known as SSRIs (selective serotonin reuptake inhibitors), they work by stopping as much serotonin from being reabsorbed at synapses in the brain and therefore leading to an increase in our mood. For antidepressants to be optimally effective in SAD, the NHS recommend starting to take them before winter and continue until spring.



Phobias Part 2 – treatments

This week’s post is the second in a 2 part series about phobias, and will focus on different types of treatment, and what works. If you haven’t already, read part 1 (see here) for more information on types of phobias and possible causes.

If you’r a regular reading of my blog, you may remember that a while back I did a post on Cognitive Behavioural Therapy (CBT) and how that can be used to treat people with phobias. The main principle is to reduce the anxiety felt by encountering the phobia stimulus, be it crowds, flying, or needles. By teaching the patient breathing exercises to help them relax and working to change the thoughts (cognitions) about the phobic stimulus, therapists can help the patient to work towards overcoming their fear. The behavioural part of this technique is gradual exposure to the thing the patient is afraid of, whilst the patient works hard to control their breathing and stay calm. This exposure can help towards changing thoughts which contribute to the phobia such as ‘if I’m in a room with a dog it will bite me’, which in turn reduces fear.

For example, take a look at the diagram below which shows how phobias remain if the fears aren’t challenged. If therapy targets the thoughts, and tests the fear, then it is likely the phobia will be treated successfully.


Another form of exposure therapy which has been used to treat phobias is known as ‘flooding’. Unlike in CBT, where the individual is gradually exposed to their fear, in this technique they are put straight in the worst situation they could imagine. This uses more behavioural techniques – as the body cannot sustain a physiological stress response for a long period of time, people begin to notice they feel calmer, even though they are in the presence of their fear. An example would be putting someone who was scared of birds in a room full of them! This also enables the individual to confront their worst fear and learn that nothing bad happens when they are in that situation.

Thanks for reading – there won’t be a post next week as I’ve got 2 interviews but I’ll be back the week after!

CBT: what is it and how does it work?

Cognitive Behavioural Therapy, Β 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, Β 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!