Psychological and social risk factors associated with development of psychopathology, controlling for biological...

To evaluate and summarize recent research investigating psychological, social and environmental risk factors for development of psychopathology in childhood, while controlling for biological (genetic) influences by using a matched sibling, twin or adoptee design.

Nineteen studies were included, of which eleven were longitudinal and eight were cohort studies. Included studies used adequate designs and statistical methods, controlled for unmeasured confounders and, in many cases, for other measured risk factors. None of the studies used the framework for environmental factors presented in the International Classification of Functioning, Disability and Health (ICF). The outcome variable psychopathology was rarely assessed using a diagnostic standard. The findings were sorted in five themes based on included exposures: 'Social support, social rejection and perceived identity,' 'Early symptoms of psychopathology,' 'Antibiotic exposure,' 'Factors in the family' and 'Nature versus nurture'.

Using twin/sibling/adoptee designs, a number of unique predictors of psychopathology were found, even when controlling for familial confounders and other specified risk factors. Future studies of psychopathology development should benefit from longitudinal, genetically sensitive designs and from use of diagnostic standards for psychopathology outcome, and should also incorporate ICF for classification of risk factors.