This is the latest in our series of posts looking at thinking difficulties in dealing with bipolar disorder. As I noted in Problems Thinking, the pioneering diagnostician Emil Kraepelin referred to “amentia” in his description of what he described as manic-depression (a term he coined) way back in the early twentieth century. Similarly, there is widespread consensus among today’s experts that cognitive dysfunction needs to be regarded as a core feature of bipolar disorder.

Typically, a sizable number of those with bipolar have to work their brains harder to accomplish a simple cognitive task and experience difficulty responding correctly to more complex challenges, even when moods are stable. The brain scans tend to reveal disruptions in various areas of the brain communicating with each other.

Part of this has to do with the overlap between bipolar and schizophrenia. Yes, the two are separate illnesses, but schizophrenia traits such as psychosis and cognitive dysfunction are no strangers to bipolar, either. The loss of cognitive function in schizophrenia may be far more profound and disabling, but even a slight loss in processing speed and related functions can pose enormous challenges.

Another part of this has to do with stress, which has a way of knocking the cortical areas of the brain off-line. No surprise - those with bipolar tend to be vulnerable to stress. Two months ago, at the NAMI national convention in Chicago, Jill Bolte Taylor, author of “My Stroke of Insight,” told us that when the amygdala (involved in fight or flight) feels safe, the rest of the brain can do its job. “Happy amygdala? That’s the bottom line for me.”

This week, we examine yet another impediment to our thinking. This concerns sleep and fatigue. In all my time listening to patients and facilitating support groups I never once encountered someone with bipolar who did not have major issues with sleep. Sleep dysregulation is a symptom of both depression and mania. "Fatigue or loss of energy" is listed as a symptom of depression, and the DSM-5 will include increased energy as a feature of mania and hypomania.

But these disturbances are hardly restricted to mood episodes. Typically, these are difficulties we are contending with every day of our lives, and when it’s not our moods that are thrown out of whack it’s our thinking. 

Even the chronically normal face similar challenges. All it takes is a bad night’s sleep for the brain to fail to boot up right. Four years ago, at the 2007 American Psychiatric Association annual meeting in San Diego, I attended a three-hour symposium devoted to hypersomnia and cognitive difficulties. The neurotransmitters of arousal are also the neurotransmitters of concentration, Stephen Stahl of UCSD told the gathering. These include norepinephrine, dopamine, acetylcholine, and histamine. Serotonin, he said is like an "anti-dopamine or anti-norepinephrine," which is why those talking SSRIs, he said, may feel flat.