Nightmares and Depression

This is a really good question. Although the research does not have a good answer, I think there might be really good answer in the practical sense. I'll try.

There is very little research on this question. The research usually has two categories of bad dreams: disturbing dreams and nightmares. Nightmares are those bad dreams that wake you up in the middle of the night. Disturbing dreams are the bad ones that you remember when you wake up after you finish sleeping. There is different data for the two types of bad dreams.

What has been generally found is that there is a correlation between nightmares and depression. But that is a correlation, and does not indicate that one is caused by the other.It does not even mean that the nightmares happened before the depression. It might be that in the people that were studied, they were depressed and then experienced nightmares. We just do not know.

If you have a history of depression or a history of abuse, there is a greater likelihood that nightmares can trigger the factors and anxiety connected to the depression or abuse and, in turn, trigger depressive symptoms. Also, if you are losing sleep because you wake up and cannot fall back asleep, you are at greater risk for all sorts of problems, but not necessarily depression (although it is possible.)

You say you are not on any new medications. That sounds like you might be on some long term medications. That need to be considered. Even though the chemicals you are putting into your body haven't changed, your body and brain are constantly changing. 

Since you do not sound like you are depressed now (only concerned about the future) you should consider doing things that can ward off depression. Look at activities that enhance a sense of well-being. If you like some sport or challenging hobby now would be a good time to reengage in that activity by dedicating two hours two or three times a week. That can include dancing or playing a musical instrument. Or you can get involved in a charity or other socially helpful organization or movement. You might be or have been active in a religious organization and rededicating yourself is another helpful tactic to lower the risk of depression. Renewing old friendships is also helpful. The involvement in such activities not only increases your resilience to depression, it enhances you sense of well-being and when you use you mind for these activities you are less likely to experience the bad dreams.

Good luck and if you need more help or information, please do not hesitate to contact me.