It would be irresponsible to publish a list of potential alien abduction signs without accompanying it with a reminder that these are merely symptoms commonly reported by people claiming to be abductees and not really the same as a checklist for a medical condition. Still, given the uniformed nature of some abduction cases, it may be equally irresponsible to withhold this information simply because of its controversy. Do you think you may be an abductee?
The first thing many people say to look for is a period of lost time. Lost time occurs when suddenly you find yourself somewhere or doing something without recalling how you got there. In the psychological field, the term is called a blackout or a memory blackout. Alcoholism is a mundane cause unrelated to the paranormal, and it's not alone. Everything from stroke to chronic fatigue syndrome can contribute to the loss of memories in the short term.
Blackouts should not be confused with simply forgetting something or losing track of time. Lost time occurs often directly after sighting an unidentified flying object or other unexplainable phenomena, but doesn't always follow such sightings. There are many in the abduction community that suggest hypnosis can help abductees tap old or blocked memories. Since blackouts are attributed to natural medical phenomena as well, each case should be considered on all the data gathered and a doctor may need to be consulted in order to check for common causes.
If you recall memories from your childhood that simply don't make sense, such as interacting with beings that you know couldn't exist in a specific place, it could be the result of a screen memory, but as memories are so unreliable it's difficult to base an abduction belief solely on this information. They are simply one of several factors that must be considered.
Pressure in the nasal cavity or behind one eye is also said to be a symptom of alien interaction. Abductees believe these are typical locations for unknown implants to be placed in human subjects, and even suggest the implants themselves can cause a person great pain if they are interfered with. Some abductees claim to have had these objects removed only to find out later that they are composed of a material not of this world.
Dreams are another important place to go. Abductees claim dreams can indicate not only whether a person has interacted with aliens, but also give hints about when and where. Do you rarely have dreams about a certain location in your childhood, but then dream regularly that aliens are appearing there or you are seeing a UFO? Abductees believe these can be indicative of alien interaction.
While these are only a few symptoms, there is also often a feeling that "something" is going on you aren't quite remembering or aware of. If this is the case, then you might consider looking into the abduction phenomenon or trying to recall when these events originate from. The very idea often sends a shudder of fear down many peoples' spines.