We have compared imagery and verbal thoughts related to suicide in bipolar disorder and unipolar depression: both groups were selected for past suicidality. Replicating previous work, the unipolar group all reported experiencing imagery related to suicide, that is, flashforwards (
3). As we had predicted, and for the first time, we found that all the participants with bipolar disorder also reported such imagery. Further, compared with the unipolar group, the bipolar group reported greater preoccupation with suicide-related images. The bipolar group rated their flashforward images as being significantly more compelling than did the unipolar group. These findings were unlikely simply to be due to a response bias in the bipolar group as there were no such between-group differences for the equivalent verbal thoughts related to suicide. Thus, strikingly, the bipolar group was more than twice as likely to report in the interview that the images made them want to take action to complete suicide.
As predicted, the bipolar group indeed had greater trait propensity to use mental imagery in general (i.e., non-suicidal imagery), in line with our recent cognitive model of the disorder (
13); this underscores their greater preoccupation with images specifically relating to suicide. The psychological literature has shown that imagining a behaviour is causally linked to then performing that behaviour (
6,
31). Our bipolar disorder sample, as predicted, specifically indicated an increased desire to act on their flashforwards and had higher scores on a measure of impulsivity. On theory-driven grounds this finding could be linked to risk for completed suicide, and is a possible contributing mechanism to the high rates of suicide found in bipolar disorder (
1). However, participants in both suicidal groups reported a preponderance of flashforwards to suicide relative to verbal thoughts of suicide, so further exploration of imagery of future events might provide a novel and much-needed general target for intervention.
In both groups, the suicidal imagery was as comforting as it was distressing. Interestingly, there are also many vivid artistic representations of the act of suicide which date back at least to the 15
th century (
32), in which suicide can be depicted in a positive light. For example, the painting
Ophelia by John Everett Millais (1829–1896) is a romantic depiction of a young woman who is drowning herself (
33). A comparison of flashforward images with their verbal counterparts showed that both groups reported greater preoccupation with these suicide-related images rather than words (verbal thoughts or narratives about suicide).
It has been suggested that engaging in suicidal fantasies may serve as an emotion regulation strategy (e.g.,
4,
34), and so that the generation of suicidal flashforwards is an
active process. In line with this argument, it seems that flashforward images can function as a means to escape or seek comfort from the examples reported by the bipolar disorder participants in our sample. However, flashforwards may also be the result of a more
passive, automatic process in which the image is unwanted and comes to mind unbidden. The type of process associated with the flashforward may also be linked to whether the image is experienced as comforting or distressing.
The degree of comfort and distress associated with the suicidal flashforwards may vary according to whether the content of the imagery is consistent with the goals of the individual or represents a conflict. For example, if an individual is distressed by the prospect of living and comforted by the idea of killing themselves, ensuing comforting emotions could be considered to be consistent with the content of suicidal flashforward imagery, potentially increasing suicide risk. However, if a patient reports both fear and comfort associated with the idea of killing oneself then the flashforward imagery may be experienced as conflictual, and represent ambivalence about suicide. Future studies could use a functional/conflicted goals analysis to investigate these aspects of suicidal imagery further as it may be a useful tool in assessing clinical levels of risk.
Our hypothesis remains that the use of imagery is particularly associated with bipolarity as a dimension of experience and psychopathology, and this is supported by this study. We would expect a contrast with other clinical groups such as schizophrenia with reduced rather than increased levels of imagery for the future compared to controls (
35). It will be of great interest to investigate whether flashforwards to suicide are present in other disorders characterized by mood instability and suicidal thinking, such as borderline personality disorder, schizoaffective disorder and so forth.
Limitations
Comparisons between bipolar and unipolar groups pose problems of experimental design because it is not entirely clear which clinical measures should be matched/controlled and which allowed to be different (because the bipolar diagnosis implies they should be different). The characteristics of much larger clinical samples suggest, for example, that bipolar depression tends to be associated with more frequent episodes and admissions and higher impulsivity as observed here. A recent consensus review of bipolar depression (
36) emphasized the gradient between bipolar and unipolar depression and the relative absence of a clear boundary between the two. Moreover, it may be generally true that a bipolar diagnosis is associated on average with more severe psychopathology. The present study cannot decide whether higher suicidal imagery should be attributed simply to severity rather than diagnosis
per se, and clinically this may not matter.
The groups did not differ in current depressed mood, current mania, state anxiety, or IQ, all of which might have influenced the results. There was a higher lifetime illness intensity in the bipolar group, with more hospitalizations, more episodes of illness, higher impulsivity scores and a tendency towards greater anxiety [see also (
37)]. Such features are present in larger representative samples of bipolar disorder patients. The homogeneity and size of our sample prevented investigation of relationships between, for example, appraisal of imagery and severity of client psychopathology. This would be interesting to explore in the future using logistic regression methods in a larger sample. Finally, we excluded severely suicidal participants in part to satisfy the conventions of our local ethics committee. Future research, perhaps in an inpatient setting (cf.,
38), could examine an actively suicidal population in more detail.
In a cross-sectional design the causal direction of any association will remain uncertain, but investigating a possible relationship between number of hospitalizations and flashforward imagery may be of particular interest. Thus, if such imagery is causally related to future behaviour, high levels of suicidal imagery would predict an increased risk of hospitalization. Larger prospective studies of at-risk individuals will be needed to partial out this or other causal effects in the evolution of mood disorder.
Lastly, our finding of very specific images associated in memory with suicidal acts appears incompatible with studies showing that bipolar disorder patients have overgeneral memories compared with controls (
39,
40). However, such overgenerality in the narrative domain may be attributable to processes for keeping specific distressing images at bay (
37).
Interestingly, the vast majority of participants spontaneously remarked that they had never discussed their suicidal images with their clinicians. This may be because typically clinicians ask for verbal narrative when eliciting suicidal ideation (“Do you have any thoughts of killing yourself?”), rather than specifically enquiring about suicidal imagery. However, we did not assess this formally, and a replication study should aim to investigate this.