Issues affecting the reliability and validity of Schizophrenia diagnosis

Hello everyone, sorry it's been a while! Thought I'd finally finish off the last schizophrenia post - diagnostic criteria, and issues affecting diagnostic validity. As usual:

Black: AO1 - Description
Blue: AO2 - Evaluation - studies
Red: AO2 - Evaluation - evaluative points/IDAs

Diagnostic Criteria

The diagnostic criteria for schizophrenia were separated by Schneider into two sets: "First-rank" and "Second-rank" symptoms, and it was suggested that having one of the 1st rank symptoms means that you are likely to have schizophrenia. The ICD (International Classification of Diseases) still focuses on 1st-rank symptoms, but the DSM (Diagnostic and Statistical Manual of mental disorders) has moved away from them.

First-rank symptoms include delusions (e.g of control, or persecution), auditory hallucinations, and thought disturbances (the belief that either your thoughts are being broadcast for others to hear, or that others are inserting thoughts into your head.)

Second-rank symptoms include disturbances of speech such as fragmentation, interruption, and incoherency, catatonic symptoms such as stupor, mutism and repeated movements, and "negative" symptoms such as apathy, avolition, a flattened range of emotional expression, and a lack of communication.

However, an issue with the concept of first-rank symptoms is that many other conditions such as bipolar disorder share these symptoms, threatening validity of diagnosis - the presence of just one first-rank symptom without any second-ranks to help make a more specific diagnosis could lead to a bipolar patient being incorrectly diagnosed with schizophrenia instead, under the ICD's diagnostic criteria.

Diagnostic Issues

Due to the two different classifications for diagnosis, criterion validity is an issue - the extent to which two different diagnostic systems agree. If schizophrenia can be diagnosed using one but not the other, either could be a potentially invalid diagnosis - one must be incorrect.

The DSM-V diagnoses schizophrenia on 5 axis: 1 and 2 for symptoms, 3 for medical conditions, 4 for social conditions, 5 for state of function. It no longer differentiates between subtypes of schizophrenia, as these are unreliable due to symptom overlap between subtypes and prominent symptom changes. To be diagnosed, a patient must have two of the criteria, one of which must be first-rank. The symptoms must be present for the last 6 months, and active for at least one.

The ICD-10 differentiates between 7 subtypes of schizophrenia, such as catatonic, paranoid, residual and undifferentiated, based on most prominent symptoms. To be diagnosed under the ICD, the patient must display one first-rank symptom, or two second-rank symptoms. It places much more emphasis on first-rank symptoms by allowing a patient to be diagnosed based on the presence of just one of them.

Comorbidity is another potential problem with schizophrenia diagnosis - the presence of one or more additional disorders occurring alongside schizophrenia makes it difficult to identify which disorder is the cause of a specific symptom, making it harder to diagnoses the correct disorders and treat them accordingly and reducing diagnostic validity.

Buckley et al (2009) analysed medical records of their schizophrenic patients, and found that 50% had depression, 47% had substance abuse disorders, 29% had PTSD, and 15% had panic or anxiety disorders. Bottes (2009) carried out a similar analysis for the Psychiatric Times, and found that 26% of schizophrenic patients had OCD, 52% had obsessive compulsive symptoms. These studies suggest that many schizophrenics have multiple disorders, and this should be taken into consideration when diagnosing patients in order to avoid an invalid diagnosis.

Contrastingly, symptom overlap can also invalidate diagnosis - many disorders share symptoms with schizophrenia, meaning that the wrong disorder could be diagnosed based on a specific, shared symptom.

Zorumski and Rubin (2013) found that bipolar disorder's most prominent symptom, severe episodes of mania, often includes delusions, hallucinations and catatonia - all symptoms that could lead to a bipolar sufferer being incorrectly diagnosed with schizophrenia.

Marsha et al (1995) found that 32% of bipolar sufferers showed 1st-rank symptoms of schizophrenia, and Carpenter (1974) found that 16% of depression sufferers showed them, suggesting that there is a clear symptom overlap between the conditions that could affect validity of diagnosis. 

Ross (1998) found that the more 1st-rank symptoms a patient displays, the more likely they are to be diagnosed with multiple personality disorder rather than schizophrenia, suggesting that 1st-rank symptoms are an indicator of MPD rather than schizophrenia specifically.

Reliability

Reliability is the consistency of diagnosis, measured by inter-rater reliability, internal consistency (if multiple patients with the same symptoms will be diagnosed in the same way) and test-retest consistency.

Several factors can reduce reliability of schizophrenia diagnosis. The main diagnostic method is the clinical interview, and individual differences between clinicians will mean different responses according to the age, personality, aptitude of the rater, as well as the bond of trust between the psychologist and the patient. These all reduce inter-rater reliability. The severity of symptoms at the time of diagnosis can affect the test-retest consistency, and deception can affect general reliability, as evidenced by Rosenhan's 1973 study.

In Rosenhan's 1973 study, 8 psychologists turned up at mental hospitals claiming to have experienced auditory hallucinations. Upon admission for schizophrenia, they stopped presenting symptoms, and were kept in for 7-52 days despite no further schizophrenic symptoms, and were given over 2000 doses of antipsychotic drugs between them. A followup on this told a mental hospital to expect pseudopatients over the next 3 months - 83 out of 193 patients were suspected of being pseudopatients by at least 1 medical professional, but they were all actually genuine.

Although based on the DSM-II criteria at the time of at least 1 auditory hallucination, the diagnoses were both reliable and valid, the admissions only showing an inability to recognise a lie, Rosenhan claimed from these results that psychiatrists could not make a consistent and accurate diagnosis. He suggested that patients' behaviour was viewed through their label of mental illness - the original set of pseudopatient psychologists' behaviour was pathologised, with note-taking observations being pathologised as "writing behaviour".

Rosenhan's conclusions lack temporal validity - the modern version of the DSM has been revised to have more stringent diagnostic criteria. Symptoms must now be present for 6 months and active for 1 month in order for schizophrenia to be diagnosed.

Once institutionalised, the participants were passive, not normal - passively keeping up the deception rather than admitting to their lie, and the relative speed of release in light of this could actually have suggested competent and efficient mental health staff.

Rosenhan's suggestion that psychiatrists cannot reliably and accurately diagnose has been challenged by: 

Jakobsen (2005) who tested 100 Danish schizophrenic patients and assessed them based on their case notes, coming to a correct diagnosis for 98% of them.

Hollis (2000) who used the DSM-IV and case notes to correctly assess and diagnose 100% of a sample of schizophrenic patients. 

These results suggest that mental health professionals are much better at diagnosing schizophrenia nowadays, and this part of Rosenhan's conclusion lacks temporal validity.

Cultural bias in diagnosis

Emic constructs are behaviours or norms that only apply to a certain number of cultures, whereas etic constructs apply globally. When an etic construct is considered to be a universal norm, this is imposing an etic. Eurocentrism leads to imposed etics in the diagnosis of schizophrenia, as the imposed etic of the DSM is used to apply a western, subjective idea of perfect mental health to non-western cultures. If people from one culture are assessing people from another, behaviour can be misconstrued, leading to an invalid diagnosis.


Cultural difference could help to explain the higher rates of schizophrenia diagnosis in some ethnic minorities. If someone is uneasy talking to a psychologist of a different ethnicity to them, they may show withdrawal, alogia, and a lack of eye contact - all of which could be interpreted as symptoms of schizophrenia, reducing diagnostic validity.

Cochrane (1977) found that schizophrenia rates in the UK and in the West Indies are very similar, and close to 1%, but people in the UK of Afro-Caribbean origin are 7 times more likely to be diagnosed with schizophrenia than those of white European ethnicity. Migration stress and socioeconomic factors were ruled out, as other ethnic groups such as South Asian that migrated at a similar time are no more likely to be diagnosed, suggesting that there is a bias that leads to racial overdiagnosis of Afro-Caribbean people.

Harrison (1997) supports the temporal validity of Cochrane's earlier research, finding that 20 years later, the gap in racial diagnosis rates had widened - Afro-Caribbean patients were now 8 times more likely to be diagnosed with schizophrenia. 

Stowell-Smith and McKeown (1999) carried out a discourse analysis of psychiatrists' reports on 18 white and 18 black psychopaths, and found that with black psychopaths there was more emphasis on aggression and potential threat to society, compared to a greater emphasis on trauma and emotional state with white psychopaths. This suggests a racial bias in the area of psychopathology that leads to biased reporting of symptoms, calling diagnostic reliability into question. 

Read (1970) gave 194 UK and 134 US psychiatrists a case report and asked them to come to a diagnosis from it. 69% of US and 2% of UK psychiatrists diagnosed schizophrenia from it, suggesting large cultural differences in behaviour interpretation and diagnostic criteria. 

Neki (1973) studied the prevalence of catatonic schizophrenia among schizophrenics in the UK and India, and found the rate was 44% in India but only 4% in the UK, again suggesting large cultural variations in behaviour interpretation and classification.

Theories of relationship maintenance

The investment model can be used as AO2 with which to evaluate either of the other theories, as it is long-term and looks at past and future commitments in a relationship, rather than focusing solely on short-term cost and reward.


Black: AO1 - Description
Blue: AO2 - Evaluation - studies
Red- AO2 - Evaluation - evaluative points/IDAs

Social Exchange Theory (SET)

Proposed by Thibaut + Kelley, this economic theory views relationship behaviour as a series of exchanges, and suggests that everyone is innately selfish, looking for the most profitable relationship that offers the most reward for the least cost. Rewards include emotional fulfilment, sex, and companionship. The theory suggests that people will only stay in a relationship if it the rewards outweigh the costs in terms of time, effort and finances. Therefore, commitment to a relationship is dependent on its profitability - we assign behaviours a subconscious numerical value, either positive or negative, indicative of their status and magnitude as either a cost or a reward.

Thibaut and Kelley also proposed that we have "comparison levels" (CL) that form the standards against which we judge our own relationships. Media, parents, family, peers and ex-partners all function as these points of comparison with which we weigh up the costs and benefits of our relationship, as well as looking to internal schemas of how a relationship should be in order to come to a judgement about the value of our relationship. Alternative comparison levels (CL Alts) are other prospective relationships with which we compare our own, evaluating the costs and benefits of leaving our partner and forming a new relationship - if the benefits of the alternative relationship are better than our current one, we are more likely to leave and start a new one. If the benefits of our CL Alts are not as good, we will stay in our current relationship.

Mills and Clark (1980) provided conflicting evidence for social exchange theory with their identification of two types of romantic relationship - the "communal couple", giving out of altruism and concern for their partners, and the "exchange couple", where each keep mental records of who is ahead and who is behind in terms of social exchange. Their suggestion that there are two types of couple challenges the degree to which SET can be applied to real-world relationships - SET only really explains the relationship dynamic between the exchange couple, not the communal couple.

Hatfield (1979) provided further evidence that challenged the validity of SET. Looking at people in romantic relationships who felt over or under-benefitted, they found that those who gave more than they received felt angry and deprived, whereas those who received more than they gave felt guilty and uncomfortable. This challenges the theory that both partners of the relationship are intrinsically selfish and aiming for maximum reward - even though the over-benefitted were getting much more out of the relationship, they felt uncomfortable and unhappy because of this, and sought to equalise the balance.

However, research by Rusbult (1983) supports the central concepts of SET. Participants completed questionnaires over a 7-month period concerning rewards and costs associated with relationships. SET did not explain the early "honeymoon phase" of a relationship where balance of exchanges was ignored, but later on, relationship costs and benefits were significantly correlated with the degree of satisfaction, suggesting that this theory can help explain maintenance of long-term relationships quite well.

An issue with SET is that it could be considered overly reductionist, seeking to explain one of the most complex human behaviours as the result of a series of simple cost/reward analyses. It focuses only on the relationship in the present, ignoring past events and future rewards and commitments, oversimplifying the process of relationship maintenance in an attempt to numerically quantify different aspects of relationship behaviour. A more holistic explanation that takes into account factors such individual differences such as the degree to which someone desires a "profitable" relationship rather than an equal one might better explain relationship maintenance in economic terms.

Another issue with SET is that it suffers cultural bias through ethnocentricity, seeking to globally apply the emic construct of desire for individual reward, imposing it as an etic. Western, individualist cultures such as those of the UK and the USA are likely to place more emphasis on the advancement of the individual in society than Eastern, collectivist cultures such as China, which are more likely to emphasise communal interest rather than individual gain. Therefore, this theory cannot necessarily be applied on a cross-cultural level, limiting its application.

A problem with SET is that it relies on two key assumptio ns: firstly, that people constantly monitor their relationship's costs/rewards and compare them with alternative relationships. However, research has suggested that it is not until dissatisfaction with the relationship that people weigh up costs/rewards and compare them to CL Alts, so this theory may be more applicable to the breakdown of relationships than it is to maintenance. Secondly, it assumes that everyone is intrinsically selfish, motivated purely through a desire for personal gain, when this may not be true - Sedikides (2005) suggested that most people are unselfish, doing things for others without expecting anything in reward.

Equity Theory

Another economic theory, this one challenges the suggestion that each partner in the relationship is only aiming for personal rewards, suggesting that fairness is more important than profit. It claims that the person who gets less in a relationship feels dissatisfied, and the person who gets more feels guilty and uncomfortable. CL and CL Alts are still valid - comparing the relationship to schemas or alternatives that might offer a fairer deal.

Walster et al suggested a 4 stage model of equity. 

• People try to maximise their profit in the relationship.
• Trading rewards occurs to bring about fairness - e.g. a favour or privilege is repaid by the partner.
• Inequality occurs, producing dissatisfaction - the partner who receives less experiences a greater degree of dissatisfaction.
• The loser endeavours to rectify the situation and bring about equity - the greater the perceived inequity, the greater the effort to equalise.

Stafford and Canary (2006) provide supporting evidence for equity theory. Asking 200 couples to complete measures of relationship equity and marital satisfaction. Satisfaction was highest in couples who perceived their relationships to equitable, and lowest for partners who considered themselves to be relatively under-benefited by their relationship. The findings are consistent with the key principles of equity theory - that people are most satisfied in a relationship where the balance of rewards/costs are fairly even and consistent. 

However, research does not support the assumption that equity is equally important in all cultures. Aumer-Ryan et al interviewed men and women in Hawaiian (individualist) and Jamaican (collectivist) universities, and found equity to be less important in Jamaican relationships. This suggests that the theory is culturally biased and cannot be applied equally to both individualist and collectivist cultures, and seeks to impose desire for equity as an etic construct rather than the emic that it actually is.

This theory has real-world application to marital therapy. Attempts to resolve compatibility issues between spouses require issues associated with inequity dissatisfaction to be resolved first, because inequity indicates incompatibility in women's eyes. In research, wives reported lower levels of compatibility than husbands when the relationship was inequitable - suggesting that there are gender differences in how equity is perceived, and the theory is not equally applicable to either gender.

Another issue with this theory is that it assumes everybody wants equality. This is not always the case - as some partners may be perfectly happy to give more than they receive in a relationship without feeling dissatisfied, suggesting equity theory cannot fully explain every type of relationship.  

Investment Model

The final economic theory of relationship maintenance is based around long-term return on investments, looking for the best possible outcome. The number and importance of  long-term investments decides whether a relationship will be maintained or whether it will break down. Investments such as houses, children, time, holidays, and assets serve as barriers to dissolution. Commitment to staying in a relationship is based on three factors:

• Satisfaction: feeling that the rewards it provides are unique
• A belief that the relationship offers better rewards than any CL Alts.
• Substantial investments in the relationship.

Impett et al provide supporting evidence for the investment model. Testing the model using a prospective study of married couples over 18 months, they found that the commitment to the marriage by both partners predicted relationship stability and success, suggesting that substantial investment in relationships helps to maintain and steady them.

Jerstad provides further supporting evidence - he found that investments, most notably time and effort put into the relationship were the best predictor of whether or not somebody would stay with a violent partner. Those who had experience the most violence were often the most committed.

The investment model is more long-term than the other economic theories of relationship maintenance, looking at past and future commitments in a relationship, rather than focusing solely on short-term cost and reward analysis.

However, an issue with the investment model is that it reflects an ethnocentric bias as an explanation of relationship maintenance. Cross-culturally, satisfaction, quality of CL Alts, and investment are not always factors that influence commitment .There may be cultural or religious pressures to stay in an unsatisfactory relationship, and in some cultures, relationship break up, especially of a marriage, is not socially acceptable. Alternatively, some cultures may have more a stigma towards one gender initiating a breakup than the other.