PSYA4- Depression

HideShow resource information
  • Created by: Mermaid.
  • Created on: 11-06-15 14:50

Intro/ Diagnosis & Classification

Depression is an affective mood disorder and it is the most common form of mental disorder. The DSM distinguishes between major depression (unipolar) and bi-polar. 10% of men and 20% of women become clininically depressed at some point in their lives. 90% of them suffer from unipolar.

Clinical depression is where everday functioning is impaired.

1 of 10

Diagnosis & Classification

Clinical characteristics of major depressive disorder:

For a diagnosis of depression, these symptoms should be present all or most of the time and should persist for longer than 2 weeks:

  • sad, depressed mood = as indicated by either subject report (feeling sad or empty), or observation made by others (e.g. appears tearful).
  • loss of interest/ pleasure in usual activities= as indicated by either subjective account or observation made by others.
  • difficulties in sleeping = some patients have a desire to sleep all the time.
  • poor appetite and weight loss or increased appetite & weight gain= e.g. significant weight loss when not dieting.
  • difficulity in concentrating= slowed thinking/ indecisiveness
  • recurrent thoughts of death or suicide
  • loss of energy
  • negative self concept, feelings of worthlessness and guilt
  • shift in activity level- lethargic or agitated- observable by others

The formal diagnosis of Depression requires at least 5 out of 9 to be present.

2 of 10

Reliability & Validity issues

Reliability- refers to the consistency of a measuring intrument e.g. a questionnaire/ scale, to assess for example, the severity of depressive symptoms. 

Inter-rater reliability-> is about assessing whether two indepedent clinicians give similar diagnoses. Low levels of inter-rater reliability related to a classification procedure suggest that it might lead to faulty diagnosis/ inappropriate treatment.

Test-retest reliability -> is about whether tests used to deliver these diagnoses are consitent over time. The DSM V (5) has emphasised the importance of test-retest reliability & has this as one of its main goals. Current measurement scales such as the Beck Depression Inventory (BDI) have been assessed for their test-retest reliability.

3 of 10

Reliability- A02

I- there is research evidence for the DSM diagnosis of depression.

J- Research on the reliability of diagnoses using the DSM classification system suggests that inter-rater reliability is 'fair to good' whereas test-retest is 'fair' at best. Zanarini also came to the same conclusion, who although finding an inter-rater reliability correlation of .80 for major depressive disorder, found a test-retest correlation of just .61 with one week between diagnosis sessions.

E- This lack of reliability is an issue  as it could lead to the wrong type of treatment being given to a sufferer of depression or misdiagnosis.

4 of 10

Reliability- 2nd A02

I- Keller suggests a number of possible reasons why the DSM diagnosis of depression might lack reliability.

J- These include the fact that for major depression to be diagnosed, 5 out of 9 symptoms must be present. When the severity of the disorder means that it's on the diagnostic threshold, a one item disagreement makes the difference on the diagnosis of the disorder.

E- Therefore suggesting that the guidelines set out by the DSM may need to be altered to increase reliability. Also, if a person is therefore wronly diagnosed with depression this can have a big impact on their life e.g. labelling.

5 of 10

Reliability- 3rd AO2

I- There is evidence to support simplifying the diagnosis of depression.

J- Zimmerman et al claim that the DSM criteria for major depression disorders are unnecessarily lengthy and that doctors frequently have difficulty recalling all 9 syymptoms; as shown by Krupinski and Tiller's study on 2,500 GPs. Zimmerman then developed a briefer definition of major depressive disorder.

E- This suggests that the DSM method is too complicated, leading to incorrect diagnoses and so lacking reliability.

6 of 10

Validity- A01

Validity-> refers to the extent that a classification system e.g. DSM, measures what it claims to measure.

Comorbidity-> is an important issue for the validity of diagnosis of mental illness, It refers to the extent that two or more conditions co-occur. E.g. research has shown that the presence of an anxiety disorder is the biggest clinical risk for the development of depression.

Content validity-> refers to whether the items in a test are representative of what is being measured e.g. the BDI is considered to be high in content validity as it was constructed as a result of a consensus among mental health clinicians.

Concurrent validity-> is a measure of the extent to which a test concurs (agrees) with already existing standard ways of assessing the characteristic in question.

7 of 10

Validity- A02

I- the diagnosis of depression requires clinicians to differentiate between several distinct subtypes of this disorder.

J- However, when McCullough compared 681 outpatients with various types of depression, they found few differences on a range of clinical, psychosocial and treatment response variables.

E- This suggests that distinctions between different subtypes of depressuin may not be valid.

8 of 10

Validity- 2nd A02

I- GP diagnoses of depression may lack validity

J- For most people, a diagnosis of depression is given by their local GP. However Van Weel-Baumgarten et al suggests that diagnoses made by GPs, rather than seconday care specialists are made against a background of previous patient knowledge and so could be biased.

E- This suggests that to get a more valid diagnosis, a secondary care specialist may have to diagnose the depression rather than the GP.

9 of 10

A03- Cultural differences

- There are cultural differences in the diagnosis of depression.

- members of ethnic minority groups are less likely than middle class white people to seek professional help.

- various explanations have been offered fo this, including the stigma attached to mental illness in some cultures. Therefore  cultural differences may impact on whether an individual gets treatment or not.

10 of 10

Comments

No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Depression resources »