Arch Gen Psychiatry -- Life Event Dimensions of Loss, Humiliation, Entrapment, and Danger in the Prediction of Onsets of Major Depression and Generalized Anxiety, A…
1/27/07 10:12 AM
T w Our twin sample was derived from 2 projects with the population-based Virginia i n R e g i s t r y f o r m e d f r o m a s y s t e m a t i c r e v i e w o f a l l b i r t h c e r t i f i c a t e s i n t h e 3 5 Commonwealth of Virginia. The female-female twin pairs come from birth years 1934 to 1974 and were eligible if both members had previously responded to a mailed questionnaire, which had a response rate of approximately 64%. Eighty-
eight percent of our sample was first interviewed face to face between 1987 and 1989 and has
subsequently been the subject of 3 additional telephone interview waves. We examine herein results from
the second wave of telephone interviews, completed between 1992 and 1994.
35 The male-male and male-female twin pairs, from birth years 1940 to 1974, were ascertained in 1993. We succeeded in interviewing by telephone 72% of those eligible. This sample was followed up in a second wave of interviews (79% of which were completed face to face), the results of which we examine herein. Interviewers were blind to information about the co-twin and previous interviews with the twin. The research protocols were approved by the institutional review board of Virginia Commonwealth
University. Signed informed consent was obtained before face-to-face interviews, and verbal consent was obtained before telephone interviews.
We assessed the occurrence during the year before interview of 14 individual symptoms disaggregating
the 9 A criteria for DSM-III-R MD.
For each reported symptom, interviewers probed to ensure that it was
due to neither medical illness nor medication use. The interviewer and respondent then aggregated these into syndromes of co-occurring symptoms about which they then asked the months of onset and offset. The diagnosis of MD was made using DSM-III-R criteria excluding criterion B2.
In addition, we asked whether there were times in the past year when participants felt "anxious, nervous, or worried," their "muscles felt tense," or they "felt jumpy or shaky inside." Positive responses to these probes were followed by an assessment of all the individual symptoms of DSM-III-R GAD. For this study, we defined GAS as a syndrome lasting 2 weeks or longer and meeting 6 or more DSM-III-R D criteria for GAD. We used this definition so that our analyses examine symptomatic differences and not duration differences between GAD-like and MD syndromes.
We examined 3 episode types: pure MD, during the MD episode, the participant never met the criteria for GAS; pure GAS, during the GAS episode, the participant never met the criteria for MD; and mixed MD- GAS, during one episode of illness without any 2-week remission, the participant met the criteria
for both MD and GAS.
As outlined previously,
in a separate portion of the interview, we assessed the occurrence by month of
11 "personal" events (assault, divorce or separation, major financial problems, serious housing problems, serious illness or injury, job loss, legal problems, loss of confidant, serious marital problems, robbery, and serious difficulties at work) and 4 classes of "network" events (serious trouble getting along with an individual in the network, a serious personal crisis of someone in the network, and death or serious illness of an individual in the network). All respondents were asked about the occurrence
of each of these individual events, which had to be temporally discrete. In an earlier wave of this study,
Kendler et al
assessed the interrater reliability for the occurrence and dating of our SLE categories and
found them to be good to excellent, with
values equaling 0.93 and 0.82, respectively. Each SLE was
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