Author’s Suspicions Confirmed: Cognitive Impairment Common in Bipolar Disorder

August 28, 2009 at 5:40 am | Posted in Cognitive Problems | Leave a comment

I’ve been on Google Scholar researching the relationship between cognitive impairment and bipolar disorder again, and the news is bleak. As I suspected, study after study finds a significant relationship between deficits in cognitive function and bipolar disorder, even when bipolar patients are in remission. I should point out that since I only have access to abstracts (I do not subscribe to a raft of medical journals), my ability to analyze the studies critically is limited. However, the studies I reviewed included several meta-analyses, which backed up the results of individual studies.

The last time I researched this topic systematically — about two years ago — researchers were still unsure if lingering depression caused the cognitive deficits they routinely observed in manic-depressive patients. A good deal of research has been published within the last two years indicating that even during remission most bipolar people show deficits in executive functions and verbal memory, in particular. Study results also suggest that, far from inhibiting cognitive function, lithium has a neuroprotective effect. Many bipolar patients would disagree with this last, but my experience certainly bears out the rest.

According to Wikipedia, executive function includes “planning, cognitive flexibility, abstract thinking, rule acquisition, initiating appropriate actions and inhibiting inappropriate actions, and selecting relevant sensory information.” Though a citation is missing for this list, these are the skills that I’ve seen referenced most commonly when discussing executive function.

Also via Wikipedia: this list of situations compiled by psychiatrists Dan Norman and Tim Shallice in which executive function plays a role:

1. Those that involve planning or decision making.
2. Those that involve error correction or troubleshooting.
3. Situations where responses are not well-learned or contain novel sequences of actions.
4. Dangerous or technically difficult situations.
5. Situations which require the overcoming of a strong habitual response or resisting temptation.

Clearly, executive function is crucial to social and occupational success.

Though this research is scary as hell, it squares with my experience, and vindicates me to a certain extent. When I worry about memory slips — often ones with serious consequences, especially at work — people tend to brush off my concerns. For me, this research confirms a set of facts that I’d suspected all along: that the cognitive deficits I’ve been experiencing are real, and that they are not iatrogenic (that is, caused by treatment). For instance, often and often I’ve experienced the inability to find a concrete noun. That started in my late 20’s, and has gotten markedly worse. At first I attributed it to mood stabilizers; now I’m pretty certain it’s a result of the disease itself.

It’s interesting to note that a good-sized subset of studies suggest that healthy first-degree relatives of bipolar people often experience the same sorts of cognitive deficits. So there’s plenty of bad news to go around. Cognitive deficits are also associated with poor occupational and social outcomes, which gives me a frisson of horror.

So, bad news this time around. I wish I could say it were otherwise.

Love to all.

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