WPA Module 2 Pathophysiological Mechanisms

WPA Components EpidemiologyEpidemiology GeneticsGenetics NeuropathologyNeuropathology NeuroimagingNeuroimaging Neuropsychology/Cognitive Psychology/Cognitive NeuroscienceNeuropsychology/Cognitive Psychology/Cognitive Neuroscience Nongenetic factorsNongenetic factors

WPA Epidemiology

WPA Epidemiology: Three Fundamental Questions What is the point prevalence?What is the point prevalence? What is the incidence?What is the incidence? What is the lifetime prevalence?What is the lifetime prevalence?

WPA Point Prevalence How many people will be diagnosed with an illness at a specific point in time?How many people will be diagnosed with an illness at a specific point in time?

WPA Incidence How many people in the population will develop the new onset of an illness during a specified time period?How many people in the population will develop the new onset of an illness during a specified time period? Difficult to estimate for schizophrenia because of difficulties in problems in identifying the time of onsetDifficult to estimate for schizophrenia because of difficulties in problems in identifying the time of onset

WPA Lifetime Prevalence What proportion of the population will develop the disorder at some time during their lifetime?What proportion of the population will develop the disorder at some time during their lifetime? Perhaps the most important statistic for schizophrenia because of its inherent chronicityPerhaps the most important statistic for schizophrenia because of its inherent chronicity

WPA Rates for Schizophrenia One-year point prevalence: 3- 10/1000 people, or approximately.5%One-year point prevalence: 3- 10/1000 people, or approximately.5% One-year incidence:.1-.7%, depending on the studyOne-year incidence:.1-.7%, depending on the study Lifetime prevalence: approximately 1% of the population worldwideLifetime prevalence: approximately 1% of the population worldwide

WPA Important Epidemiolgical Observations Prevalence is not highly variable over time or over geographical areasPrevalence is not highly variable over time or over geographical areas Found is all culturesFound is all cultures More common and/or severe in males than femalesMore common and/or severe in males than females Persists in the population despite decreased fertilityPersists in the population despite decreased fertility

WPA Lower Social Class in Schizophrenia Consistently observed in patientsConsistently observed in patients Lower social class is a result—not a cause—of the illnessLower social class is a result—not a cause—of the illness Social class of parents does not differ from the general populationSocial class of parents does not differ from the general population Lower social class is due to “downward drift,” not to social deprivation, poor nutrition, or inadequate access to health careLower social class is due to “downward drift,” not to social deprivation, poor nutrition, or inadequate access to health care

WPA Gender Differences Males have an earlier age at onset, a poorer premorbid history, more negative symptoms, a poorer outcome, and more prominent brain abnormalities as measured in neuroimaging studiesMales have an earlier age at onset, a poorer premorbid history, more negative symptoms, a poorer outcome, and more prominent brain abnormalities as measured in neuroimaging studies Women have more prominent affective symptoms and a better outcomeWomen have more prominent affective symptoms and a better outcome

WPA Genetics

WPA Genetic Questions Is the disorder familial?Is the disorder familial? Relative contributions of genes and environmentRelative contributions of genes and environment Mode of transmissionMode of transmission Location of geneLocation of gene Function and products of geneFunction and products of gene Role of the products in illness mechanismsRole of the products in illness mechanisms

WPA Genetic Methods Family history studiesFamily history studies Family studiesFamily studies Twin studiesTwin studies Adoption studiesAdoption studies Linkage and association studies, candidate genesLinkage and association studies, candidate genes Molecular genetics—functional genomics, proteomicsMolecular genetics—functional genomics, proteomics

WPA Family History and Family Studies Provide evidence for a modest level of familial transmissionProvide evidence for a modest level of familial transmission Morbid risk for parents: 5.6%Morbid risk for parents: 5.6% Morbid risk for siblings: 10.1%Morbid risk for siblings: 10.1% Morbid risk for offspring: 12.8%Morbid risk for offspring: 12.8% Second degree relatives: %Second degree relatives: %