Methodological problems of research on the psychological consequences of early

Without claiming completeness, the present section provides a review of methodological issues that need to be taken into account when planning investigations of the psychological consequences of interpersonal trauma.

First, criteria for defining and identifying the presence of interpersonal trauma are

inconsistent. Discrepancies are usually found in the specific acts that are used to define abuse as well as in age limits which are applied to distinguish early from late abuse. This non- uniformity in criteria is likely to be one of the causes of heterogeneous reports regarding prevalence rates and consequences of interpersonal trauma. Many studies on childhood sexual abuse classify individuals in a dichotomous way as either being or not being survivors of sexual abuse, without further differentiation. In doing so, researchers often collapse

various types of abusive experiences that may differ both qualitatively and quantitatively into the same group, thus precluding the detection of variation in trauma consequences as a function of different types of abuse (DiLillo, 2001). To prevent this pitfall, researchers need to make sensible distinctions between different types of interpersonal trauma and thereby form more homogenous comparison groups. Such an approach was applied in the present study in that relatively homogenous groups were formed representing individuals who had experienced different types of interpersonal trauma (distinguished according to age of onset and chronicity of the trauma). This approach could help obtain more differentiated

predictions and less ambiguous findings regarding psychological consequences of interpersonal trauma.

The second methodological aspect which requires consideration is related to the fact that research on sequelae of interpersonal trauma mostly relies on individual’s retrospective accounts of traumatic experiences as a method of assessing the presence of abuse and its characteristics (DiLillo, 2001). However, the passage of time may distort memories of abusive experiences. Some individuals may not report cases of abuse that have actually occurred, and others may report false memories of abuse. Especially details of the abusive

experience, such as the age of onset, the age difference to the perpetrator, and the duration of the abuse are prone to be reported inaccurately if the abuse dates back a long time. Inaccurate assignment of participants to comparison groups is one of the consequences that may result from individuals’ distorted reports of trauma-related memories. This, in turn, may lead to biased conclusions regarding the relationship between specific types of interpersonal trauma and indicators of psychological functioning.

Third, studies on psychological sequelae of interpersonal trauma are characterized by various sampling biases, such as homogenous samples of university students or of individuals who are seeking or undergoing psychological or psychiatric treatment for abuse-related difficulties (Briere & Elliott, 2003; DiLillo, 2001). Neither of these groups accurately represents the rates and the impact of interpersonal trauma in the general population (Briere & Elliott, 2003). As for college students, DiLillo (2001) argued that they tend to be younger, better educated, psychologically better adjusted and less diverse with regard to ethnicity and socioeconomic status than the general population of survivors of interpersonal trauma. In contrast, clinical samples are likely to be less well adjusted and to have experienced more severe forms of trauma than the general population of interpersonal trauma survivors (DiLillo, 2001). Many studies have recruited help-seeking samples that may differ substantially from different groups of abuse survivors. Perhaps these samples do not include those individuals most severely affected by interpersonal trauma because these people may not seek help as they, according to attachment theory, are likely to have lost their trust in others and the belief that other people could help and support them. In addition, it is important to bear in mind that community samples often consist of self-selected individuals who are likely to have specific characteristics which could further bias the sample (DiLillo, 2001).

Fourth, cross-sectional designs, as they are frequently used in studies on consequences of interpersonal trauma, do not permit inferences in terms of causal relationships between childhood abuse and psychological functioning. This issue was already mentioned in sections 1.5.5 and 1.5.7 referring to the association between early chronic interpersonal trauma and attachment styles. Long-term sequelae of childhood abuse not only reflect the impact of specific experiences of maltreatment but also the influence of various complex aspects of the social environment in which the abuse is embedded (Briere & Jordan, 2009). However, with

the prevalent cross-sectional designs, it is difficult to disentangle specific abuse-related effects and potential confounding variables (Maniglio, 2009).

At several points, the present thesis has referred to the advantages of prospective study designs. While prospective designs may help identify temporal links between exposure to childhood violence and adult mental health outcomes, they do not provide conclusive evidence regarding causal relationships (Margolin & Gordis, 2000). Conclusions about causation are limited because the presence and severity of violence cannot be manipulated experimentally. This means that even longitudinal studies cannot fully account for mediating or moderating variables that influence the psychological functioning of adults who were abused as children. But they have the advantage that the conditions which preceded the abuse can be assessed (Margolin & Gordis, 2009).

In an attempt to reduce the selectivity of the sample, the recruitment of participants and data collection for the present study was conducted through the Internet. It was expected that, due to the low threshold that the Internet offers for participation, a greater diversity in the sample could be obtained. However, as the scientific literature has raised concerns regarding online studies, it appears important to contrast the limitations of Web-based investigations with their advantages, as done in the following section.