Two types of disorders of the brain, bipolar spectrum disorders and Alzheimer's disease, affect the patient's mood and behavior. Bipolar spectrum disorders refer to diseases where the patient cycles between mania and depression, the two mood extremes: bipolar disorder I (mania and major depression), bipolar disorder II (major depression and hypomania) and cyclothymia (hypomania and mild depression); a fourth disorder, bipolar disorder NOS, has the distinct mood swings, but does not fall under the other forms of bipolar disorder. The Mayo Clinic notes that Alzheimer's disease is the most common form of dementia.
Age on Onset
The symptoms of each disorder start at different points of the patient's life. Alzheimer's disease is considered a disease of the elderly, with symptoms starting at about age 65. The Mayo Clinic notes that Alzheimer's disease occurs in nearly 50 percent of people ages 85 and over. Bipolar spectrum disorders, on the other hand, start when the patients are in their adolescence. The National Institutes of Health (NIH) states that the first symptoms of bipolar spectrum disorders are seen between the ages 15 and 25.
Cognitive Problems
A patient with Alzheimer's disease has severe cognitive problems, especially in more advanced cases of the disease. The patient can have memory loss, affecting her ability to recall stored memories and to form new memories. The patient can also have problems with abstract thinking and judgment. A patient with a bipolar spectrum disorder can have poor judgment while in the mania phase and some concentration problems during both the depression and mania phases. However, the cognitive problems with a bipolar spectrum disorder are not as severe as those found in Alzheimer's disease, and are only issues when the patient is in one of the mood phases.
Problems Completing Tasks
An Alzheimer's disease patient also has problems completing tasks. It begins with trouble doing sequential or procedural tasks, like balancing a checkbook. As the disease advances, the patient loses his ability to care for himself: He cannot bathe himself, use the bathroom, choose appropriate clothing and eat without assistance. A patient with a bipolar spectrum disorder, on the other hand, does not have such severe problems completing tasks, though the mood swings can impair his performance. During the depressive stage, the patient may be absent from school or work, which can impact his performance. The patient may also have issues with hygiene due to social withdrawal, but still has the ability to care for himself. Poor performance is also possible during the manic stage; however, the patient has a greater drive to fulfill his goals and do more work.
