Old age, depression and recently started hallucinating about once a week. Is this dementia?

My mother hada fall 3 months ago and has no memory of it. She has all past and recent memories. Good with recent incidents and names. Has severe spinal stenosis and was prescribed Vicodin and steroid shots. Since then started hallucinating. Initially it was thought Vicodin was the cause and was totally stopped. Had a steroid shot last week and again this week she is hallucinating. Has major depression. Could this be dementia?