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Meta-analyses

With so many scientists, papers, and perspectives, it is almost impossible to gain an accurate “big picture” understanding of anything in psychology. This is certainly true of suicide science, where thousands of papers are published each year from very different perspectives. To try to make sense of all of this information — and to try to understand why the suicide rate is increasing despite all this research — we conduct broad meta-analyses. Our hope is that these meta-analyses will tell us what we really know, what unfounded assumptions and beliefs we may carry, and where we need to concentrate our efforts to make meaningful advances in knowledge. So far, most of our published work in this area has focused on suicidality prediction. But we also have several forthcoming and ongoing projects that focus on other broad areas of suicide science.

a. Suicide/Self-Injury Prediction Meta-Analyses. There are many lists of warning signs and risk factors put out by different organizations and recommended by different experts. Curiously, there are substantial differences among many of these lists. So we wanted to know — based on over 50 years of research — which risk factors are most important? That is, which factors most accurately predict future suicidal thoughts and behaviors? All of our meta-analyses on this topic have produced the same two findings. First, no factor or small set of factors (e.g., depression, prior SITBs, risk questionnaires) predicts future self-injurious thoughts and behaviors much better than random guessing. Second, there are hundreds - and potentially thousands - of things that predict future self-injurious thoughts and behaviors slightly better than random guessing. These results were surprising to us, and they contradicted all expert-derived lists of risk factors and all known theories of suicidality. We have spent several years trying to understand what these broad patterns mean, and we think we finally have a way to make sense of them (see Paradigm/Theory section below).

b. Brain imaging and suicidality meta-analyses. Researchers have long pointed to brain abnormalities as a potential cause of self-injurious thoughts and behaviors. Several studies have detected brain abnormalities in groups of people with a history of self-injury/suicidality, but these findings are highly variable. Rarely do two studies find the same structural or functional abnormalities. To try to understand this literature better, we worked with Dr. Derek Nee's lab at FSU to conduct a meta-analysis. In short, findings showed that - based on the current literature - there are no consistent structural or functional brain imaging abnormalities among people with a history of any kind of self-injurious thought or behavior. This manuscript is currently under review. As a whole, these findings are consistent with the position that self-injurious thoughts and behaviors cannot be reduced to brain abnormalities and have no specific neural signature.

c. Systematic review of affect during suicidality. Based on popular theories, we assumed that virtually all people felt extremely negative during suicidality (i.e., during suicidal thoughts and immediately before/during suicidal behaviors). But based on some pilot studies tangential to this topic, we began to wonder if this was true. We conducted a systematic review of the literature and found that, surprisingly, very few studies had directly examined affect during suicidality, and those that had found evidence of tremendous heterogeneity.  In other words, most people feel moderately negative during suicidality, some feel extremely negative, and some even feel positive. These findings challenge some of the fundamental assumptions about suicidality and show the need for much more direct work in this area. This manuscript is currently under review.

d. Meta-analyses of treatments/interventions for self-injurious thoughts and behaviors. It is unclear which interventions work and what might moderate their efficacy. To try to gain a clearer understanding of this literature, we collaborated with Drs. Kathryn Fox at Harvard and Christine Cha at Columbia University to meta-analyze hundreds of randomized controlled trials that had included self-injurious thoughts and behaviors as an outcome. Surprisingly, interventions produced (at best) small reductions in suicidality (e.g., 10-15%), no intervention was significantly better than any other, and intervention efficacy has not improved across over 50 years of research. This manuscript is currently under review. Broadly, these findings indicate that radically different approaches to treatment may be needed to successfully treat those at-risk for suicide and self-injury. 


New Paradigm and theory

The broad patterns revealed by our meta-analyses are not consistent with existing explanations for suicidality. In fact, these broad patterns are very, very far from what would be expected based on existing theories. This has inspired us to spend the past few years coming up with a new explanation for suicidality that can account for the sum of the evidence on suicidality (not just study-specific findings or a few narrow lines of evidence). To construct such an explanation, we found that we needed to rely on fundamentally new assumptions. These assumptions constitute a totally new paradigm for suicide research, out of which many new theories may grow. We have a forthcoming paper on this new approach that will be out later this year.