Can Bipolar Disorder Cause Dementia?

We normally think of bipolar disorder as a treatable for most patients.  My experience is that if the patient is compliant with treatment (and that is a big "if"), then symptoms can be mostly controlled. 

Unfortunately, there is some evidence that some persons with bipolar disorder may eventually develop more enduring memory problems and other cognitive deficits.  I frequently have bipolar patients referred to me for assessment of memory problems or evaluation for possible dementia, and usually I do find mild to moderate problems. 

Most of the patients referred to me in this situation are in their fifties, not in their sixties, seventies, and eighties, as usually occurs when I am testing patients for dementia.  This suggests to me that there is something very different about this process than Alzheimers.  It seems to develop earlier in life, causing problems in one's job.  In addition, the patient seems to have more insight that they are having problems, whereas many of the patients with Alzheimers are brought by their family members and do not have insight that they are having cognitive problems.  However, if there is such a thing as a bipolar dementia, we do not as yet have a clear picture of what t would look like in terms of specific symptoms like to differentiate it from Alzheimers, ischemic dementia, and so on.

In a situation of testing a person with bipolar disorder, it is always possible that their memory problems are actually due to their depression.  Depression causes a generalized decrease in brain function and interferes with memory.  And so, part of the evaluation always has to be looking at the current severity of depression.  But the cognitive deficits associated with bipolar disorder do not appear to be linked to whether the person is currently depressed or not.  There seems to be something else going on.  It is possible for example that the excessive cortisol release caused by depression and mania over the lifespan have damaged the hippocampus, so that even after depression improves, there is a memory problem.

Three factors tend to make the problem worse: older age, having an onset at a younger age, and having a more severe illness overall.  There is some evidence that the more episodes of depression and mania, the greater the cognitive deficits may be.  Thus, the cognitive deficits in later life may be preventable if persons take management of their illness seriously and treat it conscientiously.

Problems occur in other aspects of brain functioning besides just memory.  These include problems with executive functioning, concentration, and visuospatial skills.

The cognitive problems appear to be persistent and sometimes severe, so that sometimes a diagnosis of dementia may be appropriate.  Usually, I do not diagnose dementia with these patients because the symptoms are not quite severe enough.  I use the milder DSM-IV diagnosis of Cognitive Disorder Not Otherwise Specified. Until we have more information about the reversible or irreversible nature of this illnes and how it responds to treatment, I prefer to use the less serious diagnosis.

The Importance of Regular Body Rhythms

Recent research has shown that in Bipolar patients, but also perhaps with Unipolar depressed patients, the 24-hour sleep/awake cycle is very important in establishing a normal mood condition. People with Bipolar Disorder are very susceptible to disruption of their moods when their 24-hour sleep/awake cycles are disrupted. Bipolar Disorder, for example, is the only psychiatric disorder which can be triggered by something positive happening in the person’s life. When a person has positive events occur it may lead to changes in their routine and in their sleep/awake cycle. When people stay up later and later, it can trigger the onset of a bipolar episode. In working with bipolar patients, we emphasize the importance of getting regular sleep, and regular waking periods. That is easier said than done, but it is important.

Research has also shown that in addition to having regular sleep/awake periods that it is important to have regular social interaction. The body sets its 24-hour cycle not just on the basis of sunlight, sleeping and waking, but also on the basis of regular social interaction. This could include something such as going to work, going to church, going at a regular time for doughnuts with a social circle, and so on. For that reason, the therapy based on this principle is called "Social Rhythm Therapy” because it involves both biological rhythms and using social events to set those biological rhythms.

For many individuals, the seasons of the year are important, and getting enough sunlight is important in stabilizing their moods. For that reason, one option is for people to stabilize their moods by walking every day at noontime for an hour. This ensures that they will get enough sunlight, and it also establishes a particular time by which the body can set its internal clock.

Persons living with Bipolar Disorder often seek out excitement and stimulation. They like change. However, too much change and too much stimulation will often trigger episodes of mania or depression.