• Unreasonable and persistent fear
• Recognition that the fear is unreasonable interferes with persons normal everyday life
• If under 18 the fear has persisted for more than 6 months
• Is not accounted for by any other mental disorder eg PTSD

• Fear of being trapped in public place.
• Repeated/unexpected panic attacks/persistent worries (more than a month) about these attacks, losing control, having heart attack

• Fear about specific objects/situations
• Most common anxiety disorder
• Fear triggered by specific stimuls and is out of proportion to what is reasonable
• Phobias in children more commonplace: duration has to be at least 6 mnths for diagnosis

• Anxiety so severe it impairs everday life
• Difference made between perfomance anxiety (giving a talk/eating a meal/going to the toilet? and social anxiety (extreme shyness)
• Both provoke anxiety and may be accompanied by panic attack

Phobias:

Issues of reliability

What is reliability?

• The consistency of a measurement (eg scale) to assess fear ratings
• Can be measured using iinter-rater reliability: if 2 independent assessors give similar scores
• Can be measured using test-retest: does the test produce same results on different occasions with same person

Phobias:Issues of reliability

Research evidence:

Skyre (1991):

Reliability of the Structured Clinical Interview

• Assessed inter-rater reliability for diagnosis of social phobia
• Asked 3 clinicians to assess 54 patient interviews using Structured Clinical interview
• High inter-rater reliability: shows diagnosis is reliable
• SCI needs lots of training to use: this may account for the high reliability

Phobias: Issues of reliability

Research evidence for reliability of

scales quicker to administer than the SCI

• Hiller et al (1990)
• Used Munich Diagnostic Checklist (MDC)
• Short, structured, self-administered
• Satisfactory to excellent test-re-test

Phobias: Issues of reliability

Research evidence for test-retest reliability

Hiller et al (1990):

Satisfactory to excellent test-retest using the shorter, structured, self-administered

Munich Diagnostic Checklist (MDC)

Phobias: Issues of relibility:

Research evidence:

Evidence for low reliability:

Kendler et al: Phone and face-to face interviews

Used phone and face-to-face interviews to assess phobias

Over a one month period they found quite low test-re-test validity

This was even lower over the long-term (8 years)

Phobias: Issues of reliability

Poor recall of fears

1. Kendler et al (1999)
2. Low reliability due to poor recall of fears
3. eg Over-exaggerate fears when recalling previous distress

Phobias; Issues of reliability:

Reasons for low reliability

Decisions made by the clinician

• Clinicans have to decide whether the symptom reaches the clinical threshold for a symptom
• One clinican might decide it does, another might not: diagnosis therefore not made: reliability goes down

Phobias: Issues of Validity

What is validity?

• Does the DSM measure what it claims to measure?
• Does the diagnosis represent something which is real and distinct from other conditions?
• Linked to reliability: a diagnosis cannot be valid if it is not reliable

Phobias: Issues of Validity

Comorbidity: What is comorbidity?

• The extent to which 2 or more conditions co-occur
• If they nearly always co-occur, they are not separate entities: diagnostic category not very useful when deciding on treatment