Possible Dangers Of Lucid Dreaming
There is no current evidence of lucid dreaming being abnormal or unhealthy in any way. However, there may be some more or less minor side effects associated with having lucid dreams. Please don’t let this scare you away from this trying this; rather, remember that with dreams you are dealing with your own subconscious mind and recklessness is not recommended.
Addiction
Lucid dreaming can be used for different purposes. Some may want to try it just for fun, using it as a "safe drug", or a personal virtual reality machine. Having fun is a fully valid application of lucid dreaming. However, be careful not to be addicted to this way of escaping your waking life. If you find that you are spending more time asleep than actually needed, or that you are thinking more about lucid dreams than your real waking life, you might want to consider taking a look at your life: if you're accomplishing the goals you have for yourself, and/or are content with the state of your life, there's likely no cause for alarm. If you see that your life needs work, you might take a break... or, you might use the tools of lucid dreaming to explore what needs to be done in your life.
Alienation
Most people have never even heard of lucid dreaming, much less ever experienced it. Some people are also less than open-minded and receptive to new ideas. Don’t be surprised if someone considers this whole phenomenon “weird” or “crazy” (which it is not). Don’t preach, either; you don't have to convince anybody.
Often people who spontaneously lucid dream, especially children, may find it surprising that not everyone does. They may even start thinking that they are the only people in the world who have lucid dreams. If they’re worried, the best support is to let them know that they’re not alone.
Dissociation
Lucid dreaming may weaken the borders between waking and dreaming, the conscious and subconscious mind, reality and fantasy. This might lead to problems of a dissociative nature. Probably the most common form of dissociation involves having problems distinguishing your waking memories from dream memories. Everyone who recalls at least one dream will have to sort out their dreams from reality in the morning. This can really be a problem for those who have previously had zero recall and, due to lucid dreaming, have had a major uptake in recall. Now, suddenly, they have all these excess, illogical memories to sort out. This is unlikely to be a major problem, but may be a big annoyance. An example is when you have actually misplaced an item, and "find it" in a dream. If you cannot distinguish dream from reality you will now think you know where that item is, perhaps even placed it where you felt sure to find it later, but when you awake it will not be there.
However, there are signs that you should watch for which indicate a larger problem may be developing. Lucid dreaming in itself should not cause these to appear in a waking state:
Ability to ignore extreme pain or what would normally cause extreme pain
Absorption in a computer game, television program or movie
Remembering the past so vividly one seems to be reliving it
Finding evidence of having done things one can’t remember doing
Not remembering important events in one’s life
Being in a familiar place but finding it unfamiliar
Seeing oneself as if looking at another person
Other people and objects do not seem real
Looking at the world through a fog or haze
Not recognizing friends or family members
Finding unfamiliar things among one’s belongings
Finding oneself in a place but unaware of how one got there
Finding oneself dressed in clothes one doesn’t remember putting on
If this has happened, and there is no other cause (e.g. drugs), take a break from lucid dreaming for a while. In fact, take a break from anything fictional for a while, at least until symptoms stop. In addition, you may consider avoiding experimentation with lucid dreaming if you have some form of schizophrenia (although very few schizophrenic people admit that they are).
PLEASE NOTE: The following possibilities are controversial and have not been proven.
Controversial: Accidentally encountering “spiritual” entities
This depends on your worldview. If dreams are a creation of your brain and nothing more, you don’t need to worry about spirits or anything similar. If you want to be on the safe side, treating objects in your dream decently and politely won’t do you any harm.
The book "The Art of Dreaming" by Carlos Castaneda has a lot to say on this subject. (See Further Reading)
Controversial: Creating bad habits or becoming a control freak
When lucid dreaming, you have the option to control the dream world in ways that are impossible in the waking world. You can, for example, make objects appear or disappear, or make people act according to your will. Some people believe this may lead your subconscious to desire this kind of control in the waking world, where it’s highly inappropriate. Also, you might be tempted to apply dream-world solutions to waking-life problems instead of actually facing them; for example, just willing bad things to go away or escaping or destroying them by superpowers. Again, this is probably more of a problem if you are not mentally stable at the outset of your dreaming process.
Controversial: Exhaustion
Some people believe that experiencing many artificially induced lucid dreams often enough can be very exhausting. The main reason for this phenomenon is the result of the lucid dreams expanding the length of time between REM states. With fewer REMs per night, this state in which you experience actual sleep and your body recovers becomes infrequent enough to become a problem. This is just as exhausting as if you were to wake up every twenty or thirty minutes and watch TV. The effect is dependent on how often your brain attempts to lucidly dream per night. If you enter into a routine of attempting to lucidly dream, you may cause recursive lucid dreams that occur at each state change.
Controversial: Inability to stop
If you have trained your mind to the point where it can step over the boundary without conscious effort, you might find it difficult to stop. Do not become alarmed if you have trouble stopping the process of lucid dreaming, it is possible to get out of the habit. As long as you truly expect to stop having lucid dreams regularly, you will. You just need to stop any further attempts to lucid dream, and within a few months the lucid dreaming will go away by itself. Remember; do not be alarmed if, even with your attempts to stop, you experience further lucid dreams. It might take a while to break the habit. If you have real concerns, it may be advisable to talk with your doctor or therapist regarding appropriate treatment, including medication.
Controversial: Undesirable false awakenings
One of the advantages of having lucid dreams is being able to change a dream or wake up if things are not turning out as planned. But sometimes, while trying to leave a dream, you'll get "stuck" in a series of false awakenings. A false awakening is when you seem to have woken up but are actually still dreaming. For example, you may find yourself waking up in your room. But once there, new things will start happening—for example, someone might visit, or you might wander outside because of an odd noise, or there might be objects all over the place. Then you might realize you're dreaming, but "wake up" immediately, and the cycle repeats until you eventually do wake up or else dream about something different. This happens mostly with nightmares or when your body is very tired, so your attempts to wake up cause false awakenings. It's a good idea to get in the habit of doing a reality check just after waking up so that you'll realize when this happens and become lucid.
When this happens repeatedly in the same night, it can be very tiring and often frightening. Not only can the belief of being fully awake in your room while being exposed to unusual situations be scary, but you also may start fearing you won't be able to actually wake up. And, depending on the content of the dream, since all your dreams tend to start in your room, you may fear what could happen once you actually do wake up.
But this is not a very common situation. Once you are lucid, it is usually easier to wake up or lose the dream than it is to keep dreaming.
She asked me whether we've met during some high-school basketball championship or something (me, basketball, hahaha), to which I replied that I don't play basketball at all, but she wasn't discouraged. I distinctly remember being captivated by her, like almost staring at her, unable not to look at her. The thing is, she was a kind of a feminine version of me: she had my green-brown eyes, my shade of wavy brown hair, my shape of mouth, and some other features as well. She was very beautiful (eat that, Freud!), but due to all this likeness I was terribly afraid that she was my sister - some I didn't know about. Like, my mother had my twin brothers 4.5 years after me, so it is conceivable she could have had a daughter in the meantime and put her away for some reason. I asked how old she was, she said 26, which only kind of reinforced my doubts. By this time, she had both her arms around my neck, trying to kiss me. I laughed and tried to politely avoid the kisses by turning my head aside 
