OCD: issues surrounding OCD: issues surrounding classification and classification and diagnosisdiagnosis• There are several issues There are several issues

surrounding the classification surrounding the classification and diagnosis of OCD that need and diagnosis of OCD that need to be assessed.to be assessed.

• These include addressing issues These include addressing issues surrounding the reliability and surrounding the reliability and validity of diagnosis.validity of diagnosis.

DSM- IVDSM- IV• The Diagnostic and The Diagnostic and

Statistical Manual of Statistical Manual of Mental Disorder (Edition Mental Disorder (Edition 4), was last published in 4), was last published in 1994. 1994.

• The DSM is produced by The DSM is produced by the American Psychiatric the American Psychiatric Association.Association.

• It is the most widely used It is the most widely used diagnostic tool in diagnostic tool in psychiatric institutions psychiatric institutions around the world.around the world.

ICD - 10ICD - 10

• There is also the There is also the International International Statistical Statistical Classification of Classification of Diseases (known as Diseases (known as ICD).ICD).

• It is produced by the It is produced by the World Health World Health Organisation (WHO) Organisation (WHO) and is currently in and is currently in it’s 10it’s 10thth edition. edition.

LabellingLabelling

• Someone who has suffered Someone who has suffered a mental disorder has to a mental disorder has to disclose that information in disclose that information in situations such as job situations such as job interviews, or they could interviews, or they could face formal action.face formal action.

• Unlike influenza, the label of Unlike influenza, the label of ‘mental illness’ stays with a ‘mental illness’ stays with a person.person.

Measuring obsessions and Measuring obsessions and compulsionscompulsions

• There are scales for the measurement of general anxiety There are scales for the measurement of general anxiety and specific scales for the assessment of obsessions and and specific scales for the assessment of obsessions and compulsions.compulsions.

• According to RUSH (2007) the best is the Y-BOCS According to RUSH (2007) the best is the Y-BOCS devised by Goodman et al.devised by Goodman et al.

• This is a semi structured interview asking about This is a semi structured interview asking about obsessions and compulsions and the extent to which they obsessions and compulsions and the extent to which they affect everyday life.affect everyday life.

• More recently Goodman has developed a new scale – the More recently Goodman has developed a new scale – the Florida Obsessive-Compulsive Inventory.Florida Obsessive-Compulsive Inventory.

Reliability and validity of Reliability and validity of DSM-IV and ICD-10DSM-IV and ICD-10

• Diagnosing a mental disorder is almost always Diagnosing a mental disorder is almost always done using the DSM-IV and the ICD-10. done using the DSM-IV and the ICD-10.

• However, there is a risk of using this However, there is a risk of using this professional jargon. (Wording in the manuals is professional jargon. (Wording in the manuals is written for specialists to understand, not written for specialists to understand, not laymen).laymen).

• The main issues surrounding the diagnosis of The main issues surrounding the diagnosis of mental disorders centre on the mental disorders centre on the reliability reliability and and validityvalidity of the diagnoses. of the diagnoses.

Reliability of DiagnosisReliability of Diagnosis

• This refers to the consistency of a measuring This refers to the consistency of a measuring instrument such as a scale to assess fear. instrument such as a scale to assess fear.

• It can be measured in terms of whether two It can be measured in terms of whether two independent assessors give similar scores: known independent assessors give similar scores: known as INTER-RATER RELIABILITYas INTER-RATER RELIABILITY

• Patients are generally diagnosed on the basis of Patients are generally diagnosed on the basis of one or more interviews with a therapist.one or more interviews with a therapist.

Inter-rater reliability and Inter-rater reliability and test-retest reliability -do test-retest reliability -do psychiatrists agree?psychiatrists agree?• Woody et al (1995) assessed Woody et al (1995) assessed

54 patients with OCD using 54 patients with OCD using the Y-BOCS and found good the Y-BOCS and found good internal consistency. Inter-internal consistency. Inter-rater reliability was was rater reliability was was reported as excellent.reported as excellent.

• However, test-retest results However, test-retest results after an average of 48 days after an average of 48 days was lower than desirable. was lower than desirable. Other studies have however, Other studies have however, found good test-retest found good test-retest reliability.reliability.

I wonder what the

other psychiatr

ist thinks?

bloke thinks?

Findings on reliabilityFindings on reliability• Brown et al Brown et al carried out two carried out two

interviews on 1400 patients interviews on 1400 patients WITH A GAP OF TWO WITH A GAP OF TWO WEEKS BETWEEN WEEKS BETWEEN INTERVIEWS. The inter-rater INTERVIEWS. The inter-rater reliability was excellent. The reliability was excellent. The most likely explanation is that most likely explanation is that compulsions provide a clear compulsions provide a clear behavioural indication of the behavioural indication of the presence of OCD. There were presence of OCD. There were some sources of unreliability- some sources of unreliability- The main one wasThe main one was

• Differences in the symptoms Differences in the symptoms were reported by patients in were reported by patients in the two interviews.the two interviews.

More findingsMore findings • Steinberger et alSteinberger et al compared DSM-IV and compared DSM-IV and

ICD-10 in their diagnoses of ICD-10 in their diagnoses of OCD. Found large differences OCD. Found large differences between the two systems between the two systems suggesting problems with suggesting problems with consistency of diagnosis. consistency of diagnosis. Using DSM-IV 95% of patients Using DSM-IV 95% of patients were diagnosed with OCD were diagnosed with OCD compared to only 46% using compared to only 46% using ICD-10 criteria. ICD-10 criteria.

• The criteria for ICD-10 are less detailed and The criteria for ICD-10 are less detailed and clear so the DSM system is preferable.clear so the DSM system is preferable.

Reliability of self report and Reliability of self report and computerised versions of Y-computerised versions of Y-BOCS.BOCS.

• These appear to yield reliability scores These appear to yield reliability scores similar to interviewer-administered similar to interviewer-administered versions.versions.

• The children’s version has also been The children’s version has also been shown to have good inter-rater reliability.shown to have good inter-rater reliability.

Validity of diagnosisValidity of diagnosisThis considers whether the system of classification and diagnosis This considers whether the system of classification and diagnosis reflect the true nature of the condition as something that is real and reflect the true nature of the condition as something that is real and distinct from other conditions.distinct from other conditions.

Discriminant validity: Discriminant validity: refers to the ability of a refers to the ability of a diagnosis to distinguish between OCD and other conditions.diagnosis to distinguish between OCD and other conditions.

• OCD can resemble the delusional beliefs of schizophrenia when the OCD can resemble the delusional beliefs of schizophrenia when the nature of the thoughts is bizarre.nature of the thoughts is bizarre.

• Obsessions and compulsions occur in a number of other disorders- e.g. Obsessions and compulsions occur in a number of other disorders- e.g. eating disorders/ body dysmorphic disorder/social phobias. DSM-1v eating disorders/ body dysmorphic disorder/social phobias. DSM-1v specifically warns clinicians not to diagnose OCD when the obsessions specifically warns clinicians not to diagnose OCD when the obsessions and compulsions are restricted to another disorder.and compulsions are restricted to another disorder.

• There can be some overlap between OCD and obsessive personality There can be some overlap between OCD and obsessive personality disorder – this people who are inflexible, obstinate, rigid and apt to focus disorder – this people who are inflexible, obstinate, rigid and apt to focus on unimportant detail. They are frequently humourless and judgemental, on unimportant detail. They are frequently humourless and judgemental, with a need for perfectionism and rigidity.with a need for perfectionism and rigidity.

Validity - Distinguishing Validity - Distinguishing between ‘worries’ and between ‘worries’ and

obsessionsobsessions• It is difficult to distinguish between It is difficult to distinguish between

obsessions and simple ‘worries’ which are obsessions and simple ‘worries’ which are not pathological (related to a mental not pathological (related to a mental disorder.)disorder.)

• Worries include things such as family, Worries include things such as family, finances and work.finances and work.

• According to Brown (1993) most clinicians According to Brown (1993) most clinicians can reliably distinguish between worries can reliably distinguish between worries and obsessions.and obsessions.

Validity of diagnosisValidity of diagnosis• It is possible that people may not produce honest It is possible that people may not produce honest

answers to questionnaires about their OCD symptoms answers to questionnaires about their OCD symptoms and this reduces the validity of any such questionnaire- and this reduces the validity of any such questionnaire- (may fear interviewer will think they have a deeper (may fear interviewer will think they have a deeper mental illness or be embarrassed). It has been estimated mental illness or be embarrassed). It has been estimated that only about 40% of people with OCD symptoms come that only about 40% of people with OCD symptoms come forward for treatment.forward for treatment.

• Patients may also be fearful of handling questionnaires Patients may also be fearful of handling questionnaires because they fear they are dirty.because they fear they are dirty.

• A further problem is that some patients may A further problem is that some patients may lack awareness of the severity and frequency lack awareness of the severity and frequency of their symptoms. Validity is likely to be of their symptoms. Validity is likely to be improved by interviewing close friends and partners. improved by interviewing close friends and partners.

Findings on ValidityFindings on Validity

• RosenfieldRosenfield et al found that patients diagnosed et al found that patients diagnosed with OCD had higher Y-BOCS scores than with OCD had higher Y-BOCS scores than patients with other anxiety disorders and normal patients with other anxiety disorders and normal controls – therefore it does distinguish OCD controls – therefore it does distinguish OCD patients from others.patients from others.

• However, However, Woody et alWoody et al found poor discrimination found poor discrimination with depression – patients diagnosed with OCD with depression – patients diagnosed with OCD were often also diagnosed with depression and were often also diagnosed with depression and it can be difficult to disentangle the two it can be difficult to disentangle the two disorders. (67% of people with OCD also have disorders. (67% of people with OCD also have depression – Gibbs)depression – Gibbs)

Cultural RelativismCultural Relativism• The incidence of OCD tends to be the same in most The incidence of OCD tends to be the same in most

countries/cultures (about 2-3%.countries/cultures (about 2-3%.

• However the symptoms are often However the symptoms are often shaped by a patient’s culture of shaped by a patient’s culture of origin.origin.

• For example a patient from India For example a patient from India may fear contamination by may fear contamination by touching a person from a lower touching a person from a lower social caste.social caste.

• This may lead to problems with diagnostic scales because This may lead to problems with diagnostic scales because symptoms checklists may be culturally based.symptoms checklists may be culturally based.

Cultural problemsCultural problems• Williams et al 2005 demonstrated that Williams et al 2005 demonstrated that

there were significant differences there were significant differences between normal populations of black between normal populations of black and white Americans in the scores for and white Americans in the scores for contamination obsessions. Black contamination obsessions. Black Americans have less interaction with Americans have less interaction with animals and have a greater fear of animals and have a greater fear of contamination from them – increasing contamination from them – increasing the diagnosis of OCD.the diagnosis of OCD.

• However – Matsunaga studied However – Matsunaga studied Japanese OCD patients and found Japanese OCD patients and found symptoms remarkably similar to those in symptoms remarkably similar to those in the West – concluding that OCD the West – concluding that OCD transcends cultures.transcends cultures.

Conclusions about Conclusions about diagnosis: Meehl (1977)diagnosis: Meehl (1977)

Suggests that mental health professionals Suggests that mental health professionals should be able to count on the diagnostic should be able to count on the diagnostic tools if they:tools if they:– Paid close attention to medical recordsPaid close attention to medical records– Were serious about the process of diagnosisWere serious about the process of diagnosis– Took account of the very thorough descriptions Took account of the very thorough descriptions

presented by the major classificatory systemspresented by the major classificatory systems– Considered all the evidence presented to them.Considered all the evidence presented to them.