Potentially treatable psychiatric problems are common in patients with degenerative brain diseases affecting movement and coordination, according to a study by Johns Hopkins scientists. Up to 80 per cent of those with either Huntington's disease or degenerative diseases affecting the cerebellum also suffer from depression, impaired thinking and changes in personality, the study found.
"Traditionally, there has been this distinction between neurological and psychiatric disorders, but it is an artificial distinction," said lead author Russell L. Margolis, M.D., associate professor of psychiatry at Hopkins and director of the Laboratory of Genetic Neurobiology.
"Indeed, the high rate of psychiatric disorders in these patients suggests that many, if not most, can benefit from treatment, even if the course of the brain disease itself cannot be reversed. Many symptoms can be eased, and the quality of life for these patients and their families can be greatly enhanced," says Margolis.
"Our findings of high rates of psychiatric disorders in Huntington's disease confirm the results of previous studies, and we believe we've found the first well-established link between serious psychiatric disorders and the cerebellum, a region at the back of the brain densely packed with nerve cells," notes Margolis.
In the study, Margolis and his colleagues conducted detailed interviews and analyzed brain images of three groups: 31 patients with degenerative cerebellar disease, 21 patients with Huntington's disease and 29 people who had no signs of brain disease. The results, reported in the August issue of the American Journal of Psychiatry, found that 77 per cent of patients with cerebellar disease had psychiatric disorders, and 81 per cent of Huntington's disease patients did so, rates nearly double those seen in healthy control subjects (41 per cent). Sixty-eight per cent of those with cerebellar disease suffered from mood disorders like depression, compared to 43 per cent of Huntington's disease patients and 31 per cent of healthy subjects. Personality change was present in 26 per cent of cerebellar disease patients, 48 per cent of Huntington's disease patients and none of the healthy patients. Nineteen per cent of cerebellar disease patients, and 71 per cent of Huntington's disease patients had either cognitive disorder or dementia.
According to Margolis, Huntington's disease primarily affects the striatum, a region of the brain below the surface of the cerebral cortex that helps regulate movement, emotion and cognition. The role of the cerebellum, the brain region damaged in the second group of patients included in the study, has traditionally been thought to be limited to regulation of movement. However, connections between the cerebellum and the cerebral cortex suggest that the cerebellum, like the striatum, might also regulate cognition and emotion. Comparing these two patient groups allowed the researchers to demonstrate that the cerebellum, like the striatum, does indeed influence cognition and emotion, and that this influence is of potential clinical significance. Individuals within the groups were matched for duration of their disease and level of impairment, so that minimally affected individuals were not compared to those with severe disease.
A third control group of people with no signs of neurological disease was also included. Rather than a random collection of people from the community, however, the researchers chose people who lived with the patients, usually the spouses, because they are likely to share some of the same psychological and social stresses as the brain-diseased patients. Margolis says spouses were chosen because one of the problems with studying psychiatric problems in patients with brain disease is determining whether a psychiatric problem is from the brain disease itself or is a psychological reaction to having a chronic, debilitating disease.
"We're really excited about what our findings mean for patients with cerebellar disease, since many of their psychiatric problems can be managed with a combination of education, medication and psychotherapy," Margolis added.
Other authors of the study are Iracema Leroi, M.D., Elizabeth O'Hearn, M.D., Laura Marsh, M.D., Constantine Lyketsos, M.D., M.H.S., Adam Rosenblatt, M.D., Christopher Ross, M.D., Ph.D., and Jason Brandt, Ph.D.
The study was funded by the National Association for Research in Schizophrenia and Affective Disorders, the National Institute of Neurological Disorders and Stroke, and the National Center for Research Resources.
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