Lesson 3 - Validity In Diagnosis

Question 1

What is validity of diagnosis in Schizophrenia

Answer 1

-refers to whether an observed effect is a genuine one
-two diagnosed patients can still differ greatly on the precise symptoms they display. Suggests that one single label of Sz is not valid
-other threats to validity include culture bias, gender bias, co-morbidity and symptom overlap

Question 2

What is Co-morbidity and Buckley’s estimation of diagnosis

Answer 2

-the extent that two patients conditions or diseases occur simultaneously in a patients
-psychiatric co-morbidities are common in Sz patients - include substance abuse, anxiety, depression, OCD and PTSD

Buckley - estimate that co-morbid depression occurs in 50% of Sz patients & 47% of patients also have a life time diagnosis of co-morbid substance abuse
-makes it difficult to get a clear and single diagnosis

Question 3

Co-morbidity and OCD + Swets - meta analysis

Answer 3

-1% of population have Sz and about 2-3% have OCD
-the two occur together more than chances would suggest

Swets - meta analysis at least 12% of Sz patients also have OCD symptoms(enough for diagnosis) and 25% displayed significant obsessive - compulsive symptoms

Question 4

What are gender differences in Sz

Answer 4

-equally affect both gender
-commonly assumed that women with Sz have better functioning prior to illness and have a better course of illness
-females tend to show fewer prior symptoms before psychotic episodes and also tend to recover better

Question 5

Gender bias and Goldstein

Answer 5

Goldstein - males are more likely to be involuntarily committed to psychiatric institutions - when they show mild symptoms due to the risk of deviant behaviour
-females are more likely to be voluntary as they are more likely to seek help
-thus most Sz work carried on males as they have higher hospital population - beta bias/gender bias

Question 6

Gender bias in diagnosis

Answer 6

-occurs when accuracy of diagnosis is dependent upon the gender
-could be because of stereotypic beliefs

Broverman - clinicians in the USA equated mentally healthy adult with mentally healthy male behaviour and therefore there was a tendency of women to be perceived as less mentally healthy

Question 7

Expand on this evaluation of validity in diagnosis of Sz
-consequences of co-morbidity - Weber

Answer 7

Weber - looked at 6M discharge record to calculate co-morbidity
-psychiatric and behaviour related diagnosis accounted for 45% of co-morbidity
-many patients with primary diagnosis of Sz also had other problems - Sz patients tend to have lower health care standard

Question 8

Expand on this evaluation of validity of diagnosis in Sz
-research support for gender bias in diagnosis - loring and Powell

Answer 8

Loring and Powell - random 290 M&F psychiatrists to read two case write ups of patients behaviour - asked to standard diagnose
-when patients said to be male or no gender - 56% diagnosis
-when female - 20% diagnosis
-shows diagnosis is influenced by gender

Question 9

Expand on this evaluation of validity of diagnosis in Sz
-differences in prognosis(symptom overlap)

Answer 9

People diagnosed with Sz rarely share symptoms
Rarely share the same outcomes
Prognosis varies:
- 20% recover previous level of functioning
- 10% achieve significant and lasting improvement
- 30% show some improvement with intermittent relapses
-an Sz diagnosis then has no predictive validity as some never recover and does appear that gender, psycho social factors and academic achievement affect outcome