MedWire News: Patients with bipolar disorder often experience intrusive memories of the past that become more distressing during depressive episodes, UK study findings show.
The results also showed that bipolar depression was associated with seeing vivid images focussed on death and suicide.
In contrast, intrusive memories were rare in hypomanic states, and these episodes were more associated with vivid, enjoyable images of future events.
“Behaviors and emotions in different bipolar states may be amplified by characteristic intrusive memories and images, suggesting novel opportunities for therapeutic intervention,” say Chris Brewin, from University College London, and colleagues.
The researchers studied the presence of memory and image intrusions in 29 euthymic patients with bipolar disorder. Intrusive memories were defined as visual images of a particular event or episode from the past that were recalled spontaneously and repeatedly, while intrusive images were scenes that came to mind repeatedly but that did not correspond directly to an event from the past and could be an imaginary situation.
The participants were asked to report on intrusive memories and images from the previous week when they were euthymic and from their most recent episode of depression and hypomania.
In all, 17 (59%), 22 (76%), and four (14%) participants reported experiencing intrusive memories during euthymia, depression, and hypomania, respectively.
For intrusive images, none were reported during euthymia, and 13 (45%) and 19 (66%) patients reported experiencing them during depression and hypomania, respectively.
Follow-up tests indicated that there was no difference in the frequency of intrusive memories between euthymia and depressed states, but they occurred significantly more during these times than during hypomania.
Intrusive images were equally prevalent during depression and hypomania, and were significantly more common during these episodes than during euthymia.
The characteristics of intrusive cognitions differed according to mood states. During euthymia and depression they appeared to encapsulate past-focused negative experiences, which were more distressing and interfered more with daily activities during depression.
Depression was also associated with vivid and distressing future-focused images that typically involved death or suicide.
In contrast, intrusive images in hypomania rarely featured past-focused negative experience; instead, they tended to be vivid positive future-oriented events involving goal-oriented events that were interpersonal in nature.
Brewin and team suggest in the journal Behavior Research and Therapy that treatments that have shown promise for reducing intrusive memories in patients with unipolar depression may also be effective for bipolar disorder patients.
The two possibilities they cite are: imagery rescripting to create an alternative representation that will compete effectively with the intruding image or memory to prevent the amplification of an unwanted mood state; and more general, meta-cognitive strategies such as detached mindfulness in response to intruding memories and images.
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