Memory problems in patients with depression increase the risk for medication noncompliance, a pilot study has found.
SAN ANTONIO—Depression and fatigue have a negative impact on memory function in patients with multiple sclerosis (MS), researchers reported at the 24th Annual Meeting of the Consortium of Multiple Sclerosis Centers. Although the study found that patients with depression had impairments in recall and recognition, patients who experienced fatigue along with depression showed even greater impairments.
“Depression, a common comorbid diagnosis in MS, is often debilitating and can result in a diminished quality of life, increased social stress, and cognitive deficits, such as reduced information processing speed and working memory,” Megan Ensley, Cognitive Coordinator at the Neurology Center of Fairfax, Virginia, told Neurology Reviews. “Additionally, a significant portion of MS patients report fatigue, a subjective lack of physical and/or mental energy that is perceived by the individual or caregiver to interfere with usual or desired activities, as either their worst symptom or the symptom that has the greatest effect on their quality of life.”
In a study of 29 patients with MS, Ms. Ensley and colleagues assessed subjects using a standardized cognitive screening battery to evaluate simple attention, verbal learning, verbal recall, verbal recognition memory, information processing speed, executive function, mental status, and mood. The researchers also administered the 36-item Short Form Health Status Survey (SF-36), using its vitality scale to evaluate subjects’ quality of life.
Almost half of all subjects (48%) reported significant fatigue, 79% reported clinical depression, and 41% reported both fatigue and depression. Of the subjects who were both depressed and fatigued, 83% scored below expectations on one or more cognitive screening elements, while 73% of those reporting depression without fatigue (38% of subjects) scored below expectations.
For information processing speed, 78% of depressed and fatigued subjects and 75% of depressed-only subjects were impaired. In verbal learning, 67% of the depressed-fatigued group and 50% of the depressed group were impaired. Recall was impaired in 67% of depression-fatigue subjects and 50% of depressed subjects. Recognition was impaired in 67% of the depression-fatigue group and 13% of the depression-only group. Executive function was hindered in 33% of depressed and fatigued subjects and in 63% of depressed-only subjects. Language skills were impaired in 78% of depressed and fatigued subjects and 50% of the depressed-only group. Simple attention was impaired in 22% of the depressed and fatigued subjects and 38% of the depressed-only group.
“The patients reporting clinically significant depression and fatigue appear to have had more difficulty with verbal learning, delayed recall, and recognition than patients only reporting clinically significant depression,” Ms. Ensley said. “This information suggests that fatigue may be exacerbating the cognitive difficulties of patients already reporting depression. In the clinical setting, this may mean that patients do not have the cognitive energy to attend to their doctor’s instructions once they have left the office. This could be particularly detrimental if a patient is unable to recall important details, such as what prescriptions to take and when.
“Patients with MS are most likely to discuss their experience of memory loss, depression, and fatigue with their clinician, and as such it is important for clinicians to assess the potential impact of depression and/or fatigue on such memory difficulties, as this information could be diagnostically important for distinguishing between an organic versus functional etiology of the memory dysfunction,” she added. “This information could be significant for clinicians in determining the best course of treatment. It can be presumed that treating the patient’s depression and/or fatigue will greatly improve cognitive function … subsequently leading to an overall enhancement of quality of life.”
—Rebecca K. Abma