Psychological and Social Factors Flashcards
What did the WHO Ten-Country study suggest?
1980s - 1990s: rate in which new cases of psychotic disorder emerge in populations over time
- Narrow schizophrenia = classical symptoms : no significant differences across populations
- > schizophrenia uniform around the world
- Broad schizophrenia: wider variations in rates of schizophrenia
- > not uniform across populations
What did meta-analyses reveal after the WHO Ten-Country study (McGrath et al., 2004)?
- 100 studies reported incidence rates of schizophrenia (top and bottom 10% rates removed)
- Variation in incidence found across geographical areas: 7.7 to 43 per 100,000
= 5 fold variation in incidence - Incidence higher in males than females, urban areas, and migrant groups
Which findings are amongst the most replicated findings in the epidemiology of schizophrenia and psychotic disorders?
Incidence rate of schizophrenia is higher in:
- males than females
- urban areas
- migrant groups
How does the relative risk of schizophrenia vary according to where people lived in their childhood (Pedersen and Mortensen, 2001)?
- Most urbanised area: 2 times higher risk of schizophrenia than in rural areas
- Incidence reduced in individuals who moved out of urban environments
- Incidence increased when people moved in urban environments
- > increased interest in social factors in psychotic disorders
What is the dose response effect?
The higher the population density, the higher the risk
What do the meta-analysis on schizophrenia and migration show (Kirkbride et al., 2006)?
- Incidence is higher in all migrants (compared to non-migrant populations) (weighted relative risk: 2.9)
- Incidence is higher in developing countries (weighted relative risk: 3.3)
- Incidence is higher in majority of black population (weighted relative risk: 4.9)
What do meta-analyses show on psychosis and ethnicity show (Kirkbride et al., 2006; Morgan et al., 2006; Fearon et al., 2006)?
- Higher incidence of psychotic disorders amongst individuals who’ve migrated from countries with majority of black population (Caribbean, Sub-Saharan Africa)
- Migrant effect: incidence varies from different migrant groups (higher in groups are more visible minorities)
What do meta-analyses show on variations in the incidence of psychotic disorders between generations (Bourque, van der Ver and Malla, 2011)?
- No reduction in incidence rates
- Similar or even higher rates for 2nd generation
- Increased incidence is not primarily due to migration BUT rather living as minority in a majority population
What is the incidence of common psychotic experiences within the general population?
Up to 10%
What characterises the common psychotic experiences in the general population?
They share the qualities of psychotic experiences without the level of intensity, frequency or severity of psychotic disorders
- short-lived hallucinations
- low-level delusions and strange beliefs
- > share the same risk factors as psychotic disorder
What is the problem with studies that focused on psychotic experiences?
They rely on assumptions that psychotic experiences might give a clue to the risk of developing a psychotic experience
- psychotic experiences share same risk factors as psychotic disorder
What does the research on the social factors in psychosis relate to?
Psychotic experiences in the general population
What are the social risk factors of psychosis at the neighbourhood/area level?
- Ethnic density
- Population density
- Social fragmentation
- Deprivation
- Crime
What are the social risk factors of psychosis at the individual-level?
- Separation in childhood (e.g. abuse, bullying)
- Isolation in adulthood (e.g. life events, discrimination)
What did researchers in Chicago find out about the neighbourhood factors in the occurence of mental disorders (Faris and Dunham, 1939; Park and Burgess, 1925)?
- Occurence of schizophrenia much more common in the middle of city (downtown, fragmented areas)
- high levels of geographical / social mobility, crime, proportion of migrant groups, single person households or rented accommodation
- Incidence decreased when going out of those areas (heart of city)
What was the key issue with studies on neighbourhood/area factors of psychosis?
Is psychosis due to social drift or social causation?
- whether people have developed disorder prior to moving into these areas or is it living in these areas that increases the risk?
What is the role of social fragmentation in the development of psychotic disorders (Allardyce et al., 2005)?
- The higher the level of fragmentation, the higher the level of admission for schizophrenia
- Effect for social fragmentation persists even after adjusting for deprivation
- > living in impoverished/deprived areas is not key factor
- Key factor: living in disjointed and fragmented environments
What does ethnic density refer to?
The proportion of people from minority ethnic groups living in a certain area
What is the role of ethnic density in the risk of schizophrenia?
- As level of ethnic density decreases, relative risk of schizophrenia increases
- > risk of schizophrenia might be higher where people feel marginalised or isolated
- > living in areas with greater levels of social support and integration might protect against developing schizophrenia
- > Social environment and social risk factors might be important in relation to psychotic disorders
Can social drift explain why a decreased level of ethnic density is associated with an increased relative risk of schizophrenia?
No
- most areas with low proportions of minority ethnic groups tend to be wealthier areas
-> developing a severe psychotic disorder is unlikely to cause social drift in wealthier areas
What is adversity?
Difficult and unpleasant experiences or circumstances
What are the identified indicators of childhood adversity (Wicks, Hjern, Gunnell, Lewis and Dalman, 2005)?
- Rented apartment
- Low social economic status
- Single parent household
- Unemployment
- Receiving welfare benefits
- > increased incidence of psychotic disorder in relation to each indicator
What is the role of childhood adversity in the risk of psychosis (Wicks, Hjern, Gunnell, Lewis and Dalman, 2005)?
Linear increase with cumulative effect
- the more of indicators of childhood adversity are present, the greater the risk of schizophrenia or other psychotic disorders
- adversity in childhood is associated with later risk of psychotic disorder AND with other mental disorders in adulthood (e.g. depression, anxiety)
What did the meta-analysis of Varese and colleagues (2012) on childhood adversity show?
- 2 to 3 fold increased risk of psychosis in relation to any childhood adversity
- Each type of adversity was associated with increased risk of schizophrenia or psychosis
What are the methodological issues in most studies on childhood adversity and psychosis?
- Most studies have been in relation to psychotic experiences, looking at their occurence over short time periods, rather than psychotic disorder
- Psychotic experiences are associated not only with psychosis but other disorders such as depression and anxiety
Often:
- small studies
- non-first episodes
- poorly-selected controls
- recall of past experiences
- multiple exposures (combined effect)
- no consideration to age, type, severity, duration
What is the problem of multiple exposures in studies on childhood adversity in relation to psychosis?
There’s a combined effect of the experiences of adversity
- many types of adversity don’t occur in isolation but occur together
- > most people exposed to one, tend to be exposed to multiple forms of adversity
- > lack of specificity
Why do must studies of childhood adversity have been in relation to psychotic experiences rather than psychotic disorder?
- Very difficult to study psychotic disorder, especially in relation to childhood factors
- Onset of psychotic disorders is in mid to late 20s
- Psychotic disorders are rare (affecting 10 to 20 per 100,000 per year)
What is required to prospectively study psychotic disorder?
- Follow large number of people
- Over long period of time
What did the study of Arseneault and colleagues (2011) on childhood trauma and the risk of psychosis show?
- Children age 8-10, with follow up at age 12, associations with psychotic experiences are with bullying and maltreatment (not accident)
- > some specificity on the type of event and the impact on risk of psychosis
- > events that have an intention to harm (directed experiences) seem to reflect higher incidence of psychosis
- Combined effect bullying + maltreatment is in excess of the effect of bullying and maltreatment alone
- > important to consider multiple factors together
What did the study of Cutajar and colleagues (2010) on sexual abuse and the risk of psychosis and schizophrenia show?
Odds ratios of any psychotic disorder and schizophrenia
- are higher for sexual abuse with penetration (2.6 ; 3.3)
- than for sexual abuse without penetration (1.3 ; 1.4)
- > increased risk for severe level (with penetration), not for those sexually abused without penetration
- > Important to consider specificity of type and severity of experience in relation to psychotic disorder
What did the meta-analysis of Beards and colleagues (2013) show on adult adversity and life event in relation to psychosis and psychotic experiences?
- Life event were three times more common amongst those with psychosis compared to those without
However, methodologically weak
- high heterogeneity
Differences in:
- the way experiences and life event have been measured
- sample selection and size
- time period of life events
What did the household survey of Morgan and colleagues (2014) show on life events and psychotic experiences?
- 15% reported having experienced psychotic symptoms at some point in their lives
- in relation to a range of life events
- Events that involve intention to harm had strongest effect on likelihood of psychotic experiences
- > factor of type and severity of events
- The more events people are exposed to, the greater the risk of psychotic experiences
- very large effect for those exposed to more than 3 events
- Evidence of linear trend
What is the role of discrimination in the risk of psychotic disorder (Arisen and Nazroo, 2002; Veling et al., 2007)?
- Evidence of linear trend
- > the higher the level of discrimination felt, the higher the risk of psychotic disorder
- Greatest risk of psychotic disorder for those who reported exposure to physical racial harassment (vs verbal)
What is the concept of causal partners in psychotic disorders?
- Cluster of component causes contribute to onset of disorder
- Psychotic disorders are complex multifactorial disorders (not caused by single factor)
- > Potential interactions between different types of risk factors
- Impact of environmental or socio-environmental factors on risk of psychotic disorder is dependent of pre-existing genetic vulnerability
- > epigenetic interactions
What did the study of van Os, Pedersen and Mortensen (2004) show on urbanity and familial liability in the causation of psychosis?
- Higher risk of psychosis amongst those who were both exposed to urban areas AND who had family history of psychotic disorder
What did the study of van Os, Pedersen and Mortensen (2004) show on urbanity and familial liability in the causation of psychosis?
- Higher risk of psychosis amongst those who were both exposed to urban areas AND who had family history of psychotic disorder
What were the consequences of advances in molecular genetics for research?
Researchers began studying genetic risk directly
- candidate genes
- polygenic risk scores (total genetic risk)
-> future research would then combine polygenic risk scores and analyses of environmental factors, to study gene-environment interactions
What did the study of Clarke and colleagues (2011) show on the combination of neurodevelopment risk markers of psychotic disorders?
- Some increased risk of psychotic disorders for each of the 2 neurodevelopment risk markers
- Higher risk when both were present
- > Combined effect
What is the impact of the combination of abuse in childhood and adversity in adulthood (Morgan et al., 2014)?
Effect of the two combined is greater than the sum of each individual effect
What is the evidence on the role of a person’s attributional style in the risk of psychosis?
- Those who attribute experience and difficulties to external phenomena are at higher risk of psychosis
(experiences of threat and violence might increase external blame) - Plausible psychological mechanisms BUT circumstantial evidence (still thin)
What is the evidence on the role of the dysregulation of the HPA axis in psychosis?
Some dysregulation of HPA axis in those with psychotic disorder and those with psychotic experiences
What is the evidence on the role of the dopaminergic system in psychosis?
Dopaminergic system is affected in those with psychotic disorder and those exposed to difficult experiences
