Summary with the article: Childhood adversities and adult psychiatric disorders in the national comorbidity survey replication I: associations with first onset of DSM-IV disorders - Green e.a. - 2010

In many studies, significant associations were found between adult mental disorders and childhood adversities (CA). Most studies cover only one CA. However, CA’s are clustered and studying only one CA causes overestimation of a single CA. Therefore, most CA studies have been based on insufficient and complex models. The objective of the current study is to examine associations with twelve different CAs with the first onset of DSM-IV disorders. 

What method was used in this study?

Participants were recruited and existed from a sample of the US household population. They completed a face-to-face survey: the NCS-R lifetime diagnostic interview (CIDI) that was administered in two parts. The interview generates diagnosis based on the DSM-IV criteria. The CIDI assesses age at the onset of the mental illness.

How were childhood adversities measured?

In the NCS-R, there are twelve dichotomous childhood adversities that can occur before the age of 18. The CAs that can occur prior to this age are divided in four categories:

1. Interpersonal loss: parental death, divorce or separation from parents or caregivers.

2. Parental maladjustment: mental illness, substance abuse, criminality and violence.

3. Maltreatment: physical abuse, sexual abuse and neglect.

4. Other CAs: life-threatening childhood physical illness or extreme family economy adversity.

Parental criminality, family economic adversity and sexual abuse were measured with a baseline NCS test. Parental illness was assessed by the family history research diagnostics criteria interview. Family violence and physical abuse was measured by a modified version of the conflict tactics scale. Neglect was measured using questions from children welfare studies. Lastly, life threatening physical illness was measured by the standard chronic conditions’ checklist.

How was this study analysed?

For analysing the answers, tetrachoric factor analysis or promax rotation was used. This way, intercorrelation between the CAs were examined. Associations of childhood adversities with lifetime disorders was estimated with the discrete-time survival analysis. The researchers controlled for age at the interview, sex and ethnicity. They also adjusted for the associations of CAs with temporally secondary disorders through early-onset disorders that affected secondary disorders. The Akaike information criterion was used to select the best multivariate model. The best-fitting model was estimated in subsamples per disorder. Subsamples included: mood, anxiety, disruptive behaviour and substance use disorders. The model also included life course stage and the conjunction of life course stage and class of disorder. The population attributable risk proportion (PARP) was computed and measures the proportion of observed outcomes that would have been prevented without the presence of CAs.

What were the results of this study?

About 53.4% of the participants reported at least one CA. The most common CA was parental divorce, family violence, family economic adversity and parental mental illness. There was a mean of 3.2 CAs in participants that reported more than one CA. Three meaningful factors were found:

1. Maladaptive family functioning (MFF): parental substance abuse, criminality, domestic violence and neglect.

2. Parental death and other loss associated with economic adversity.

3. Parental divorce associated with economic adversity.

Although the odds of disorder onset increase with more CAs, they increase at a decreasing rate. CAs also proved to be significantly associated with adds to develop a DSM-IV classified mental illness. Each MFF CA is associated with each disorder class whereas other CAs are less consistent.

Life-course stage was not associated with a specific connection between CA and DSM-IV mental disorder, but parental death, physical abuse and physical illness were significant only in childhood. CAs turned out to be more strongly connected with the onset of temporally primary disorders and less to secondary disorders. The association between CAs and onset of disorder is largely positive. It turns out that CAs explain 41.2% of disruptive behaviour disorders, 32.4% of anxiety disorders, 21% of substance abuse disorders and 26.2% of mood disorders. Furthermore, the CAs can explain a higher proportion of childhood-onset disorders.

What did the researchers conclude?

First, associations elevated with length of the recall can cause recall bias. This could have caused underreporting of CAs by people that have a mental illness. However, the trends were compared to historical data and any bias in prevalence estimated was disregarded in the total population. Also, researching mental disorders using retro -and prospective data remains important because it can avoid the problem of downward bias due to of the systematic sample attributions that can be based on this long-term data.

The researchers conclude that CAs have a powerful connection to the onset of several types of primary mental disorders throughout life course. Often, CAs are nonspecific in their associations with mental disorders. Therefore, it can be useful to examine multiple outcome to avoid narrow interpretations. Also, some CAs have higher associations with outcomes than others. Sometimes these associations attenuate with age. The present results are consistent with previous research stating most children are exposed to clustered childhood adversities. Future research should consider multiple CAs in predicting mental illnesses. It should examine the fact that CAs with onset of DSM-IV disorders persists into adulthood. It turns out about 25% of new onset disorders in adulthood is related to a child adversity. The final comment on further research is that the associations between CAs and disorder onset/persistence should be examined. The connection between CA and disorder persistence is different from the relation between CA and disorder onset.

What are study limitations?

1. The first limitation is that data is gathered in a retrospective way which can cause recall bias. The best way to assess this issue is to regard retrospective studies as being the upper bound and prospective studies the lower bound.

2. The second limitation is that the list of CAs was not exhaustive. There is the possibility factors such as: the number of ill parents, could have contributed to the association. The goal of the current study was a broad overview, which inevitably overlooks details.