Multiple sclerosis (MS) can affect the brain. Sometimes a change in mood, behavior or personality is the only sign of the illness.
With MS, damage can happen anywhere in the nervous system. That leads to wide variations in symptoms.
People with MS have a higher rate of depression. That is partly because of the impact of the illness on a person's life. In addition, MS can cause changes in brain chemistry that can lead to depression.
MS can affect memory and intellectual functioning. Attention problems may develop. Problem solving can become impaired. Information processing may slow. The illness can cause confusion and disordered thinking. Personality may be affected by any of these symptoms.
The front parts of the brain (frontal lobes) are often involved when there is a personality change in MS. The frontal lobes have influence over language, judgment and problem-solving. It molds social and sexual behavior. Thus, a wide range of changes are possible.
MS can reduce a person's emotional control. The person may get more impulsive or socially inappropriate.
Apathy and indifference can also happen. The person may become more detached. He or she may have trouble understanding the impact of behavior on others. The person may be less spontaneous or may appear less expressive.
These observations do not cover every possibility. And just because a person has MS does not mean it is causing changes in feelings or behavior. Sometimes a mood problem or a thinking problem is the cause.
Psychotherapy and education about these problems (for the affected person and family members) can help everybody adjust. Of course, also continue to pursue whatever MS treatment the neurologist recommends.