Reversible cognitive disorders are due to conditions that severely affect a person's cognition (thinking abilities). However, if the condition is treated, the person's thinking abilities return to normal or near normal levels. Thinking abilities can change due to many possible situations or conditions. People who have mild forms of mental illness may often experience difficulties with their thinking abilities. In many cases, when the mental disorder can be treated, the person may regain all or some of their disrupted thinking abilities.
A condition that was previously referred to as pseudodementia is now more appropriately referred to by many clinicians as the dementia syndrome of depression or neurocognitive disorder due to depressed mood. This condition can happen in people who have very severe cases of depression that significantly affect their thinking abilities.
The Diagnosis of Depression
In the DSM-5 the diagnosis of depression (officially known as major depressive disorder) happens when a person meets at least five or more of nine specific symptoms that happen during the same two-week period. One of the symptoms must either be displaying a depressed mood or a loss of interest/ pleasure in daily activities. The symptoms must lead to a decrease in the person's normal level of functioning. The symptoms also cannot be due to some other mental disorder or medical condition.
A diagnosis of major depressive disorder is not made when a person displays normal changes in their mood such as sometimes being sad over the type of things that happen to most people. A diagnosis of major depressive disorder represents a diagnosis of a severe psychological disorder. This disorder most likely requires some form of treatment for the person's mood to improve. One of the major categories of the symptoms that happens are cognitive symptoms such as troubling thinking, remembering, or concentrating. When a person has a very severe onset of depression, their cognitive symptoms may be so severe that the person appears to have a form of dementia. This is most common in elderly people, but can happen in younger people as well.
The Dementia Syndrome of Depression
The prevalence of depression in elderly people is lower overall than it is in younger groups of people. However, older people with depression will more often have more physical symptoms. These physical symptoms often cause problems in their ability to think, concentrate, and make decisions. When a doctor is diagnosing possible dementia in any elderly person, they should consider the effect of depression or other issues such as anxiety on the person's symptoms. Younger people who have symptoms that look like dementia, but who do not have a family history of dementia would should make a competent clinician investigate the cause of their thinking issues. Often, the first potential causes that may be responsible for these types of dementia-like symptoms would be major depressive disorder.
Symptoms of the Dementia Syndrome of Depression
Some people who have severe depression may appear as if they have dementia. However, clinicians can use specific rules to determine if depression may contribute to the person's cognitive problems. A few of these include:
- The person appears to have dementia, but also has moderate to severe depressive symptoms.
- The person displays many of the physical signs of significant depression. This particularly includes very slowed thinking processes, very slowed and drawn out speech, and slow physical movements.
- A person with depression complains of having cognitive problems and can explain when they began, what they are, etc. Generally, someone with dementia will be more likely to try and cover up their thinking issues or will not be aware of them.
- If there are issues with memory, the person's performance on tests of memory improve when they are given reminders, cues, or asked to recognize information from a list. In many forms of dementia, these memory aids are not helpful.
- The examination of the person reveals that there is depression and that the start of their thinking problems has been relatively recent. The exam also reveals that problems happened relatively quickly, and there is no evidence that the person has had a stroke or other condition that can explain these symptoms.
A person's thinking abilities may even be affected by mild levels of depression. When people are treated for their depression, they will often experience a return of their thinking abilities. People with severe cognitive issues that are believed to be due to depression should also show a return of their abilities if the depression can be successfully treated. However, in some cases that include other possible causes of the person's decline in cognition, a full return of the person's thinking abilities may not happen. In general, clinicians expect a significant return in the person's thinking abilities if their depression can be successfully treated.
Treatments for Depression
Depression can be treated with medications, psychotherapy, or a combination of both. There are many medications that are now used to treat depression. Different types of antidepressants are likely to cause different side effects. These medications will typically take a few weeks before the person begins to show improvements in their mood. Other medications, such as mild stimulant medications, may also be used to help the person function better physically and to concentrate in the short term. The use of psychotherapy has been shown to be at least as effective as the use of medications to treat depression. It also can help the person to develop skills that will help them not to have serious issues with depression in the future. However, psychotherapy for depression most often requires a longer time commitment. For people who have the dementia syndrome of depression, it would most likely be used in combination with medications.
The treatment of the depression will very often result in significant improvements in a person's thinking abilities. However, there are studies that suggests that having a history of major depressive disorder is a risk factor for the development of later issues including developing dementia. People who have been diagnosed with moderate to severe depression that resulted in significant cognitive problems should be followed closely by their doctors. This can help to identify any early warning signs of potential dementia or other cognitive disorders.