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What is depression?

I’ve said it before, and I’ll say it again; dismissing the concerns of a genuine depression sufferer on the grounds that you’ve been miserable and got over it is like dismissing the issues faced by someone who’s had to have their arm amputated because you once had a paper cut and it didn’t bother you. 
Dean Burnett, Guardian 2014

Symptoms of depression may include the following:

  •  Difficulty concentrating, remembering details, and making decisions

  •  Fatigue and decreased energy

  •  Feelings of guilt, worthlessness, and/or helplessness

  •  Feelings of hopelessness and/or pessimism

  •  Insomnia, early-morning wakefulness, or excessive sleeping

  •  Irritability, restlessness

  •  Loss of interest in activities or hobbies once pleasurable, including sex

  •  Overeating or appetite loss

  •  Persistent aches or pains, headaches, cramps, or digestive problems that do not ease even with treatment

  •  Persistent sad, anxious, or "empty" feelings

  •  Thoughts of suicide, suicide attempts


The World Health Organisation reports that depression is the leading cause of disability worldwide, and is a major contributor to the overall global burden of disease.


Globally, more than 300 million people of all ages suffer from depression. This means that one in five adults will experience significant levels of depressive symptoms and 1 in 12 will experience depression severe enough to warrant treatment of some kind.  These figures are likely to be an underestimate of the problem, given that many people do not seek help or recognise their symptoms as signalling depression.  

Depression remains more commonly reported in women than in men (although this may be a result of women being more regular users of health services in general, and therefore it may be more likely that their symptoms will be identified and diagnosed).


Diet appears increasingly likely to contribute to the significant difference in numbers of women diagnosed with depression compared to men.  Men have been found to make 52% more serotonin than women (a potential protective factor), which according to our current understanding of the biology of depression would make men far less prone to depression than women.  Some researchers have attributed some of this difference to dieting, particularly in the teenage years.  Low calorie diets reduce the amount of the essential amino acid tryptophan.  Tryptophan is a vital ingredient in the production of serotonin.  (Meat, milk and eggs are the most common sources of tryptophan).


What are the symptoms? Isn't it just feeling low?

Depression is different from usual mood fluctuations and short-lived emotional responses to challenges in everyday life. Especially when long-lasting and with moderate or severe intensity, depression may become a serious health condition. It can cause the affected person to suffer greatly and function poorly at work, at school and in the family. 

A key distinction is also made between depression in people who have or do not have a history of manic episodes. Both types of depression can be chronic (i.e. over an extended period of time) with relapses, especially if they go untreated.  

Depression which consists of both manic and depressive episodes is called Bipolar affective disorder.  These episodes are separated by periods of normal mood. Manic episodes involve elevated or irritable mood, over-activity, pressure of speech, inflated self-esteem and a decreased need for sleep.


There tends to be lots of overlap between depression and anxiety, both in terms of symptoms and in terms of diagnosis.  It’s thought that as many as 90% of patients suffering from depression also exhibit symptoms of anxiety, such as interruptions of sleep, ability to concentrate and panic. 


How is depression measured?

For purposes of Class 1/2 certification, depression is assessed using a questionnaire (The Hamilton Depression Scale) which is completed by the examining medical officer.  This measures all common symptoms of depression and their severity.  The symptoms which are being assessed include mood, (sadness, hopeless, worthlessness), guilt, restlessness and insomnia, work and leisure interests, cognitive functions (speech, motor activity), anxious thoughts and symptoms, libido, eating and weight changes, insight into illness,  thoughts about suicide, paranoia, and changes in thinking.  The score is based upon the medical officer’s assessment of the pilot’s current state. 

Other measures commonly used in assessing depression (but not for licence certification) are self report measures, such as the Beck Depression Inventory (you can take it yourself here).  Many people find it useful to complete these type of instruments weekly, to monitor their progress.  They are also regularly used in the treatment of depression. 

Depending on the number and severity of symptoms, a depressive episode can be categorised as mild, moderate, or severe. An individual with a mild depressive episode will have some difficulty in continuing with ordinary work and social activities, but will probably not cease to function completely. During a severe depressive episode, it is very unlikely that the sufferer will be able to continue with social, work, or domestic activities, except to a very limited extent.

Depression has been called the “common cold’ of mental health.  Whilst this is a great metaphor, it greatly underestimates the impact it has on everyday life.

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