Alternate Methods of Scoring
The ETI-SR was demonstrated to be a valid measure of early trauma. Individual domains of physical, emotional, and sexual abuse, and general trauma, were found to be internally consistent (α = 0.78–0.90) and valid (r = 0.39–0.47 for correlation with the CAPS; ). Of the different scoring strategies, none added additional information above the simple method of adding up the number of events that ever occurred; subsequent analyses were therefore performed with this simple scoring technique.
Properties of ETI Using Full List of Items
All domains showed high internal consistency (Cronbach coefficient α > 0.7). Items with the highest correlation to total score in the general trauma domain (r > 0.4) included personal accident (T2), observing the death or serious injury of others (T13), witnessing violence (T15), and being victim of assault (T21; ). Items in the physical domain with the highest item-total correlations (r > 0.41) included being slapped (P2), being punched (P4), having objects thrown at you (P6), and being shoved (P8). Weakest correlations were seen for being spanked with a hand (P1; r = 0.34), which was also most frequently endorsed (85%) along with being hit with objects (68%). These 2 items were highly correlated, suggesting that they were measuring the same thing. Emotional abuse items were all highly intercorrelated and had high correlations with emotional abuse domain total score, ranging from 0.52 to 0.76, with the lowest item-total correlation for parents controlling one’s life (E6). Among the sexual abuse items, being made to pose for suggestive photographs (S13) and being forced or coerced to perform sexual acts for money (S14) were both very infrequently endorsed (4%) and showed the weakest associations with ETI sexual abuse domain totals. Apart from these items, the other sexual abuse items showed a strong association with total score, with r values ranging from 0.47 to 0.77.
For general trauma items, correlations of >0.2 with the CAPS were seen for natural disaster (T1), personal accident (T2) or injury (T3), separation of parents (T7), being raised in someone else’s home (T8), serious injury or illness of a sibling (T10), witnessing death or serious injury of others (T13), divorce or separation of parents (T14), witnessing violence (T15), family member with mental illness (T16), parents with alcoholism (T17), parents with substance abuse (T18), victim of armed robbery (T20) or assault (T21), victim of rape (T22), or seeing someone murdered (T23; ). For physical abuse, all of the items had a correlation of >0.2 with the CAPS except for being spanked with a hand (P1). All of the emotional abuse items were correlated with the CAPS. The ones with the highest correlations (>0.3) with CAPS included being often put down or ridiculed (E1), often ignored (E2), often told you were no good (E3), often treated in a cold or uncaring manner (E5), and parents often failed to recognize your needs (E7). Sexual abuse items correlated at >0.2 with the CAPS included all items except someone performing anal sex on you against your will (S11) and being forced to pose for sexy photographs (S13).
Factor Analysis of the ETI-SR
Factor analysis within the general trauma domain identified one primary factor that accounted for 16% of the variance and included exposure to natural disaster, personal accident, injury, illness, witnessing violence, and being victim of assault. Other factors represented items that were overlapping, redundant, or measuring similar events. These included death of a friend and serious illness/injury of a friend, death of parent and serious illness/injury of parent, separation/divorce of parents or divorce of parents, rape or having someone close to you raped, seeing someone murdered and having someone close to you murdered, family violence and alcoholic parents, death or illness of a sibling, and family mental illness. Together, all of these factors accounted for 51% of the variance. For physical abuse, two factors emerged that accounted for 50% of the variance, one related to being spanked (P1) or hit with objects (P5) (13%), while the second factor included all of the other items. For emotional abuse, there was only one factor including all of the items that accounted for 57% of the variance. For sexual abuse, there were two factors, one accounting for 8% of the variance including being forced or coerced to pose for sexy photographs (P13) and being forced or coerced to perform sexual acts for money (P14). Coercive sexual acts like having someone perform anal sex or oral sex on you against your will also loaded onto this factor to some degree. The second factor included all of the other sexual abuse items and accounted for 44% of the variance.
Selection of Items for Short Form
Items were selected as candidates for a possible short version of the ETI. Several items showed high correlations with each other or clustered in a factor analysis, suggesting that these items were redundant or were measuring similar constructs. In the general trauma domain, there was a high correlation between death of parent (T5) and illness of parent (T6) (r = 0.33), separation or divorce of parent (T7) and divorce of parent (T14) (r = 0.82), personal accident (T2) and injury (T3; r = 0.38), death of sibling (T9) and serious illness of sibling (T10; r = 0.36), death of friend (T11) or injury of friend (T12; r = 0.41), parental alcoholism (T17) or substance abuse (T18; r = 0.29), seeing someone murdered (T23) and having someone close to you murdered (T24; r = 0.36), and being raped (T22) and having someone close to you raped (T25; r = 0.36). Other items were weakly correlated with the total score or were infrequently present, including being raised in home other than parents (T8), observing death or injury of others (T13), personal theft (T19), personal armed robbery (T20), stressful job (T26), POW (T27), combat (T28), death of child (T29), miscarriage (T30), and death of spouse (T31). Some items were redundant with the physical and sexual abuse domains, including personal assault (T21) and rape (T22). Based on factor analysis, item-total correlations, interitem correlations, considerations of redundancy, and correlations of individual items with the CAPS, a shortened list of items was selected ().
Frequency of Endorsement and Item-Total Correlations of Items on ETI-SR Shortened List of Items (N = 288)
For physical abuse, factor analysis showed two factors, with one factor related to being spanked with a hand (P1) or being hit with objects (including being spanked with a belt; P5), and the other related to all 7 remaining items. The items spanked with a hand (P1) and hit with objects (P5) were shown to be frequently endorsed, have a low correlation with PTSD symptom severity, and to overlap with one another. The item being choked (P7) was highly correlated with other items and felt to be redundant/overlapping, while being tied up or locked in a closet (P9) was more infrequent than other items. For these reasons, these 2 items were dropped, in addition to spanked with a hand (P1) and hit with objects (P5).
For emotional abuse, there was only one factor, and all 7 items were highly intercorrelated. Items retained based on correlation with PTSD symptom severity included being often put down or ridiculed (E1), often ignored (E2), often told you were no good (E3), often treated in a cold or uncaring manner (E5), and parents often failed to recognize your needs (E7).
Two primary factors emerged for the sexual abuse domain. One factor was primarily related to being forced to pose for suggestive photographs (S13) and to perform sex acts for money (S14); this factor was also related to the coercive sexual acts of being forced to have anal sex against your will (S11). All other items were related to the other factor. Of these, several were seen as having necessarily occurred if subjects were exposed to other, more advanced forms of sexual abuse. These included being exposed to comments about sex (S1), being exposed to flashing (S2), someone spying on you in the bathroom (S3), and someone watching you undress (S4). Other items, including someone performing oral sex upon you against your will (S10), or someone trying to have sex with you but not actually doing so (S12), were more uncommon or not correlated with PTSD symptom severity. Retained items are shown in .
Properties of the Short Form ETI
The short form of the ETI-SR therefore had 11 general trauma items, 5 physical abuse items, 5 emotional abuse items, and 6 sexual abuse items, for a total of 27 items (, ). The properties of the short-form ETI were compared with the full list of items. Domain scores for the short list correlated highly with the original list for general trauma (0.91), and physical (r = 0.94), emotional (r = 0.97), and sexual abuse (r = 0.97). The short form showed a similar internal consistency for the individual domains (0.70–0.87; ) and the long form (0.78–0.91) (). Both the short form () and the long form () were able to discriminate patients with known associations with trauma from comparison subjects. There was also a similar validity based on the CAPS measurement of PTSD symptoms for the long form (r = 0.37– 0.47; ) and the short form (r = 0.32– 0.44; ). For items on the shortened list, there was a correlation of 0.23 to 0.56 of individual items with domain score in the general trauma domain, 0.37 to 0.63 in the physical abuse domain, 0.56 to 0.75 in the emotional abuse domain, and 0.58 to 0.78 in the sexual abuse domain. There was also a high level of internal consistent as measured by Cronbach α for the domains of general trauma (0.70), and physical (0.75), emotional (0.86), and sexual abuse (0.87) trauma domains. Factor analysis of the shortened list showed a high factor loading (>0.5) for all items within the physical, emotional, and sexual abuse domains. For general trauma, there were three primary factors. One corresponded generally to “random events,” including natural disaster (T1), serious accident (T2), serious injury of a friend (T12), and seeing someone murdered (T23), all with factor loading >0.55. The second factor of “dysfunctional family events” included separation of parents (T7), witnessing family violence (T15), and alcoholic parents (T17; with factor loading >0.6). Another factor of “family accidents” included serious injury to self (T3), parent (T6), sibling (T10), and family mental illness (T16), all with factor loading >0.6. These items in general were less random and were related to physical abuse items—that is, events that could occur in a household where physical abuse was prevalent.
Mean ETI Scores in Healthy Subjects, Trauma Controls, and Patients With PTSD, BPD, and Depression Using Restricted Number of Itemsa
Properties of ETI Using Restricted Number of Items