Diagnosis and classification of depression

DSM & ICD 

5 symptoms must be present including depressed mood most of the day, every day:

• Difficulty in sleeping
• Shift in activity
• Loss of interest & pleasure in activities
• Poor apetite and weight change
• Recurrent thoughts of death or suicide

Distinguishes between Major Depressive Disorder (MDD) and Manic Depression (bi-polar)

Relaibility refers to consistency between different sets of results.

Can be tested using:

• Test-retest
• Inter-rater reliability

Keller:

• Inter-rater relaibility was 'fair to good' and test-retest was only 'fair'
• A one item disagreement is enough to make a difference between MDD and a less serious illness

Validity refers to the extent that a diagnosis represents something that is real and distinct from other disorders and the extent that a classification such as DSM measures what it claims to measure.

Can be measured using: 

• Content validity
• Concurrent validity 

Can be affected by:

• Co-morbidity 

Evaluation:

• Diagnoses made by GP's could be biased as they are made against a background of previous patient knowledge
• Sub-types may not be valid because McCullough found few differences in a range of clinical, psychological and treatment response
• The off of having suicidal thoughts was 5 times higher in patients with MDD alone 

Culture may impact the diagnoses of depression.

White people are more likely so seek help whereas in some cultures there is stigma attached to mental illness and they see depressive symptoms as social problems.

White people see depression as an illness requiring treatment.