Review
Copyright ©The Author(s) 2017.
World J Psychiatr. Jun 22, 2017; 7(2): 77-88
Published online Jun 22, 2017. doi: 10.5498/wjp.v7.i2.77
Table 1 The advantages and limitations of methods for investigating biological risk factors in individuals with postpartum psychosis
Investigational methodAdvantages of methodLimitations of method
Clinical biochemistry or gene expression analysesDirect assessment in patient or “at risk” groupsDifficult to access central nervous system; peripheral changes may not reflect central functional abnormalities
Possibility of identifying peripheral biomarkers for PP riskPotential issues with obtaining consent for samples
Substantial fluctuation of markers with participant demographics, experiences and treatments
Possible issues related to reverse causation, i.e., are abnormalities a cause or consequence of the disorder?
NeuroimagingDirect assessment of brain structure, function or chemistry in patient or “at risk” groupsCannot easily be performed during psychotic episodes
Substantial exclusion criteria for procedure
Limited resolution; cannot provide information on most neurochemical, cellular or molecular abnormalities
Substantial fluctuation of measures with participant demographics, experiences and treatments
Possible issues related to reverse causation, i.e., are abnormalities a cause or consequence of the disorder?
GeneticsDNA can be readily obtained from patient or “at risk” groups from peripheral tissuesLow power of genome-wide studies as a consequence of low prevalence of the condition; possibility of false positives and negatives
DNA sequence is stable and unaffected by variability in patient’s circumstances
Possibility of identifying biomarkers that can predict risk at an early stage
Few issues with reverse causation
Porcine infanticide modelSome degree of face validityQuestionable relevance of animal behavioural phenotypes to PP symptoms
Direct access to brain tissue for detailed examination and DNA for genetic studiesDifficult and expensive to breed and maintain
Not readily amenable to pharmacological studies; predictive validity unclear
Difficult to systematically assess all brain regions
STS-inhibition mouse modelSome degree of face and predictive validityQuestionable relevance of animal behavioural phenotypes to PP symptoms
Direct access to brain tissue for detailed examinationFace and predictive validity require further confirmation
STS deficiency unconfirmed in PP cases, hence construct validity unsubstantiated
Relatively cheap to breed and maintain
Amenable to pharmacological and genomic studies