Intoday’s society, depression is one of the principal causes of disabilityworldwide, affecting more than 400 million individuals’ length and quality oflife. According to the 2013 Global Burden of Disease Studies, it is consideredthe worlds most prevalent and widespread mental health disorder (Vos, et al.,2013). It has been said that roughly 1 in 6 individuals in the UK reportsexperiencing depression each year (McManus, et al., 2016). If left untreated atits worst state, it can lead to suicide (WHO, 2017). With the rise of depression amongstindividuals, it poses a threat to public health and population, resulting inthe demand for its treatment to increase drastically.
Themedical definition of depression according to the Oxford dictionary is a mentalcondition characterised by feelings of severe hopelessness and dejection, inaddition to the feelings of inadequacy and guilt, which is also accompanied bythe lack of energy and changes in appetite and sleep” (Oxford EnglishDictionary, 2010). This condition can also be called Clinical Depression wherethe symptoms in individuals can often be present on their own or coexist witheach other.Thereis no specific reason as to why certain individuals experience depression, butit is said that it can be caused by abnormalities in factors such as genetic,environmental, psychological and social factors (Bradley, 2016). These abnormalfactors tend to trigger the onset of the disorder; an interaction between themcan also worsen the depression itself (WHO, 2017). These ideas are furtherexplored in Chapters 2, 3 and 4.
It is important to consider these factors asthey tend to affect the severity of depression and the individual’s response tothe antidepressant treatment.Thediagnosis of depression is currently done using any of the two majorclassification systems available. This is either the World HealthOrganisation’s – International Classification of Disease -10 (ICD-10) system orthe Diagnostic and Statistical Manual (DSM-IV) system (Bebbington, 2004). Both thesesystems screens the affected individual, and, determines the severity of thecondition by establishing the number and severity of the symptoms present, inaddition to determining the degree of functional impairment (NICE, 2009). Thecriteria of diagnosing depression using ICD-10 is that patient must have atleast 4 depressive symptoms out of the 10 available, whilst on the other hand,DSM-IV requires at least 5 depressive symptoms out of the 9 available (SeeTable 1 for symptoms).
However, both systems require the presence of keysymptoms (*) and for the symptoms to have been present for 2 weeks or more toprovide a diagnosis (Nice Clinical Guidelines, 2010). Through this, healthcareprofessionals are able to categorise the individual into one of thesecategories – mild, moderate or severe depression and provide appropriatetreatment.