"The course of mental health after miscarriage and induced abortion: a longitudinal, five-year follow-up study"
, by Anne Nordal Broen, Torbjørn Moum, Anne Sejersted Bødtker and Øivind Ekeberg, published in BioMedCentral BMC Medicine, 2005, 3:18 doi:10.1186/1741-7015-3-18.
This is apparently a follow-up study to the one we posted on 9/17/14, by several of the same researchers.
Miscarriage and induced abortion are life events that can potentially cause mental distress. The objective of this study was to determine whether there are differences in the patterns of normalization of mental health scores after these two pregnancy termination events.
Methods: Forty women who experienced miscarriages and 80 women who underwent abortions at the main hospital of Buskerud County in Norway were interviewed. All subjects completed the following questionnaires 10 days (T1), six months (T2), two years (T3) and five years (T4) after the pregnancy termination: Impact of Event Scale (IES), Quality of Life, Hospital Anxiety and Depression Scale (HADS), and another addressing their feelings about the pregnancy termination. Differential changes in mean scores were determined by analysis of covariance (ANCOVA) and inter-group differences were assessed by ordinary least squares methods.
Results: Women who had experienced a miscarriage had more mental distress at 10 days and six months after the pregnancy termination than women who had undergone an abortion. However, women who had had a miscarriage exhibited significantly quicker improvement on IES scores for avoidance, grief, loss, guilt and anger throughout the observation period. Women who experienced induced abortion had significantly greater IES scores for avoidance and for the feelings of guilt, shame and relief than the miscarriage group at two and five years after the pregnancy termination (IES avoidance means: 3.2 vs 9.3 at T3, respectively, p < 0.001; 1.5 vs 8.3 at T4, respectively, p < 0.001). Compared with the general population, women who had undergone induced abortion had significantly higher Hospital Anxiety and Depression Scale (HADS) anxiety scores at all four interviews (p < 0.01 to p < 0.001), while women who had had a miscarriage had significantly higher anxiety scores only at T1 (p < 0.01).
Conclusion: The course of psychological responses to miscarriage and abortion differed during the five-year period after the event. Women who had undergone an abortion exhibited higher scores during the follow-up period for some outcomes. The difference in the courses of responses may partly result from the different characteristics of the two pregnancy termination events.
Background: ...A recent review of post-1990 research articles  concluded that anxiety symptoms are the most common adverse response, and that our understanding of abortion as a potential trauma has increased. Recent studies have explored the traumatic aspects of abortion. One study reported that 1% of participants suffered from post-traumatic stress disorder (PTSD) two years after the event , and another reported that 10% of women were traumatized (according to a high Impact of Events Scale [IES] score) six months after the induced abortion . In a previous study  in which the subjects were the same as those evaluated in this study, we found that 18.1% of women were classed as "cases" (> 19 points on one or both of the IES subscales) two years after an induced abortion.
...Regarding the nature and direction of possible selection bias, a former study has shown that those who do not participate in studies such as this have more problems than those who do participate .
...Another limitation arises from the selection of the participants. As described in the Methods section, there was an overrepresentation of women who coped well with the termination among those who completed the study. This was particularly evident for women who had had an induced abortion. Therefore, the results at T2, T3 and T4 may have been biased towards overly favorable mental health outcomes.
...The elevated scores for guilt, shame and IES avoidance for women who had had an induced abortion may require more attention. Several recent studies have focused on the relationship between guilt, shame and PTSD [33-35]. One article states that "the affects of shame and guilt in particular can be very disabling, in so far as they ... affect the experience of the self and social behaviour, contribute to later psychopathology, effect help-seeking, and impede emotional processing of the event." . In our previous article , we found that feelings of guilt and shame 10 days after a pregnancy termination predicted high IES avoidance scores two years later (a statistical interaction effect showed that this tendency was even more important for women who had had an induced abortion). It is possible that feelings of guilt and shame associated with the induced abortion contribute to a slower improvement in mental health.
(All those [##] footnotes in the above excerpts have links to the research cited, at that site. It's a long but mostly-easily understood article on the research. If you're a statistician, those parts will make more sense to you, but if you aren't, it won't detract from the readability of it.)
So the short of it is, no, you're not crazy to feel guilt, shame, or try to stuff down those feelings after an abortion, or to feel like you have PTSD. It happens to more of us than Planned Parenthood's own personal research arm, the Guttmacher Institute, wants any of us to believe. But we do know better.