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CBT Improves Memory Functioning in Patients with Bipolar I Disorder

According to a recent study published in the Journal of Behavior Therapy and Experimental Psychiatry, cognitive behavior therapy (CBT) improves explicit memory recall and reduces explicit memory bias for negative words in patients with bipolar type I disorder.  Both mania and depression are associated with impaired memory.  In tests in which participants learn words and are then asked to recall them, bipolar patients, both manic and depressive, have been shown to recall less words overall but more words with negative emotional valence than non-bipolar or depressed people.  This suggests that bipolar disorder affects global memory performance and introduces a negative memory bias.  The present study sought to examine if a CBT intervention would improve global memory performance and reduce the negative memory bias in bipolar I patients using a randomized, wait-list controlled design.

Participants (n=73) were bipolar I patients aged 18-65 on a treatment waiting list.  The experimental group (N=53) was given CBT in addition to medication, and the control group (N=20) was treated with just medication.  Participants were assessed for memory at baseline and at a 6-month follow up.  In this procedure, they were given 30 words that had either positive, neutral, or negative affective valence (10 words for each category).  They were first asked to rate the emotional valence of each word on a one to five scale.  Then, they were told to write down as many words as they could recall.  Participants were also assessed for disorder levels with the Hamilton Depression Rating Scale (HDRS), Mania Rating Scale (MRS), and the Hamilton Anxiety Rating Scale (HARS), and completed the Dysfunctional Attitudes Scale (DAS).

Before treatment, there were no significant differences between the two groups in the number of words recalled in any affective valence category or in the severity of bipolar symptoms.   At the follow-up, 11 patients from the experimental group had dropped out.  Of the remaining 42, significant improvements on the HDRS, HARS, and DAS were observed.  No such improvements were observed in the control group.  The primary effect of interest, explicit memory recall, was also improved in the CBT group.  Futher, recall for positive and neutral words was significantly improved, and recall for negative words significantly decreased in this group.  No memory effects were observed in the control group.

These results indicate that CBT is not only effective in improving the general dysfunctional symptoms of bipolar I disorder, but also in improving explicit memory functioning and reducing negative memory bias in patients.  By reducing negative memory bias, CBT may help modify bipolar patients’ cognitive schemas and can contribute to decreased cognitive vulnerabilities such as the negative memory bias. Further, CBT techniques for regulating both positive and negative thoughts and emotions can allow patients to modify unhelpful and intrusive past memories.

Docteur, A., Mirabel-Sarron, C., Guelfi, J.-D., Rouillon, F., & Gorwood, P. (2013). The role of CBT in explicit memory bias in bipolar I patients. Journal of Behavior Therapy and Experimental Psychiatry, 44, 3, 307-311.