Freud argued that dreams are really just our repressed subconscious desires being given an outlet. By examining the private content of these dreams we can identify our true desires but also what's really bothering us. SSRIs otherwise known as antidepressants cause especially vivid dreams or even nightmares because they make more serotonin available to brain. There are certain medications that make our dreams incredibly vivid because they change the chemicals in our brain which will ultimately change how our neurons interpret information consolidate memories and process our emotions.