The short answer is that you may be inadvertently causing mood swings if your loved one is experiencing Alzheimer’s disease or dementia. When a person is experiencing dementia, they lose the ability to manage their own moods because they lose their memory skills and rational thinking skills. Worse, those are also the skills needed to interpret or understand why someone else might look unhappy or seem distant, so they cannot help but take your moods personally. If you look worried, they will become worried. As a companion, you need to be aware of this and use your nonverbal cues to communicate a positive mood. Whatever your face or voice communicates is the mood they will mirror back to you. And it will be absorbed and shared long after you’ve left the room.