Emotional Mental Imagery Abnormalities in Monozygotic Twins With, at High-Risk of, and Without Affective Disorders: Present in Affected Twins in Remission but Absent in High-Risk Twins.

Background: Mental imagery abnormalities feature across affective disorders including bipolar disorder (BD) and unipolar depression (UD). Maladaptive emotional imagery has been proposed as a maintenance factor for affective symptomatology and a target for mechanism-driven psychological treatment developments. Where imagery abnormalities feature beyond acute affective episodes, further opportunities for innovation arise beyond treatments, such as for tertiary/relapse prevention (e.g., in remitted individuals) or primary prevention (e.g., in non-affected but at-risk individuals). The aim of our study was to investigate for the first time the presence of possible mental imagery abnormalities in affected individuals in remission and at-risk individuals for affective disorders using a familial risk design. Methods: A population-based cohort of monozygotic twins was recruited through linkage between the Danish national registries (N=204). Participants were grouped as: affected (remitted BD/UD; n = 115); high-risk (co-twin with history of BD/UD; n = 49), or low-risk (no co-twin history of BD/UD; n = 40). Twins completed mental imagery measures spanning key subjective domains (spontaneous imagery use and emotional imagery) and cognitive domains (imagery inspection and imagery manipulation). Results: Affected twins in remission reported enhanced emotional mental imagery compared to both low- and high-risk twins. This was characterized by greater impact of i) intrusive prospective imagery (Impact of Future Events Scale) and ii) deliberately-generated prospective imagery of negative scenarios (Prospective Imagery Task). There were no significant differences in these key measures between affected BD and UD twins in remission. Additionally, low- and high-risk twins did not significantly differ on these emotional imagery measures. There were also no significant differences between the three groups on non-emotional measures including spontaneous imagery use and cognitive stages of imagery. Conclusions: Abnormalities in emotional prospective imagery are present in monozygotic twins with affective disorders in remission-despite preserved cognitive stages of imagery-but absent in unaffected high-risk twins, and thus do not appear to index familial risk (i.e., unlikely to qualify as "endophenotypes"). Elevated emotional prospective imagery represents a promising treatment/prevention target in affective disorders.

Neural response during emotion regulation in monozygotic twins at high familial risk of affective disorders.

PURPOSE: We investigated the neural correlates of emotion regulation and -reactivity in adult unaffected monozygotic twins with a co-twin history of unipolar or bipolar disorder (high-risk), remitted or partially remitted twins with a personal history of unipolar or bipolar disorder (affected) and twins with no personal or first-degree family history of unipolar or bipolar disorder (low-risk). METHODS: We assessed 37 high-risk, 56 affected and 28 low-risk participants. Participants viewed unpleasant and neutral pictures during functional magnetic resonance imaging and were instructed to down-regulate their emotional response through reappraisal or mental imagery, as well as to maintain the elicited emotion. RESULTS: After adjusting for subsyndromal depressive symptoms, bilateral supplementary motor areas, posterior dorsal anterior cingulate cortices and the left frontal eye field showed less activity during reappraisal of unpleasant pictures in high-risk than low-risk participants. Notably, affected participants did not differ from high-risk or low-risk participants in neural response during reappraisal. There were no group differences in ventrolateral prefrontal cortex seed based functional connectivity during reappraisal or neural response during mental imagery or emotional reactivity. CONCLUSION: Lesser response in dorsal midline areas might reflect familial risk related abnormalities during down regulation of emotional reactivity through reappraisal.