In one sentence, describe what the following article is about:

If your nightmares are the result of an underlying condition such as sleep apnea, narcolepsy, REM disorder, or restless leg syndrome, receiving treatment for these conditions should help to reduce nightmares.  If your nightmares are related to anxiety, depression or PTSD, certain forms of therapy or medications might help to alleviate these conditions and lessen nightmares. In particular, a drug known as Prazosin is often prescribed to help patients with PTSD, anxiety and panic disorders, and can alleviate nightmares. It is important that you speak to your doctor to figure out a treatment option that is best for you. Eating before bed can trigger nightmares, as food speeds up your metabolism and sends signals to your brain to become more active. Therefore, it's a good idea to cut out bedtime snacks, particularly those that are high in sugar. . Stress can contribute to nightmares, so take some time to relax throughout the day and aim to go to bed with a calm, clear mind.   Yoga and meditation are both good activities for relieving stress and clearing the mind. Consider taking a class, or simply practice for a few minutes each day in the comfort of your own home.  Other activities such as reading, knitting, running or just spending more time with your family and loved can also help to relieve stress. Taking a hot bath before bed can help you to unwind after the stresses of the day and leave you feeling calmer and more relaxed . Certain medications can increase the likelihood of nightmares, so speak to your doctor if you feel this might be an issue for you.  Anti-depressants and certain blood pressure medications are often responsible for causing nightmares, so speak to your doctor about switching to a different drug. Sometimes a change in dosage or coming off a particular drug can cause nightmares, in which case the bad dreams should subside once your body adjusts. Although nightmares may cause sleep deprivation, sleep deprivation can also cause nightmares. Therefore, taking steps to improve the quality of your sleep can help to prevent nightmares.   Make your bedroom a relaxing environment. Keep your bedroom neat and tidy, make sure it's dark enough and avoid temperatures that are too hot or cold. Make sure your bed is comfortable. Use a white noise machine to block out any undesirable sounds. Reserve your bedroom for sleeping - working in your bedroom may cause you to associate it with stress.  Get more physical exercise. Tiring yourself out with physical exercise is a great way to improve your sleep. Find an activity that you enjoy, whether it's running, strength training, dancing, rowing or rock climbing and work out 3 to 5 times a week. Schedule it for the morning if you can. Just don't exercise right before bed - it will leave you too amped up for sleep.  Cut back on your caffeine, alcohol and nicotine intake. These substances can interfere with your sleep, so it's a good idea to cut them out or at least cut down. Also try to avoid drinking, smoking or consuming caffeine less than 3 to 4 hours before bedtime.  Avoid blue light. The light emitted from electronics like phone, computers, and tablets can suppress sleep hormones and affect the quality of your sleep. Avoid using these devices close to bedtime. Imagery rehearsal treatment is a type of cognitive therapy which has been found very effective in reducing nightmares in PTSD and insomnia patients.  With imagery rehearsal treatment, the patient is encouraged to imagine an alternate ending to their nightmares - one with a more pleasant or satisfying outcome - while they are still awake.  For example, if you're dreaming you're being chased, you could imagine the monster that's chasing you, when it catches you, saying "tag, you're it" and it's really a game of tag. If you're dreaming that you're falling, you could imagine that a parachute opens up and saves you.   Sometimes this is done orally, other times the patient is asked to write down, draw or paint the alternate ending to their nightmares.

Summary:
Treat any underlying disorders. Avoid eating before bed. Reduce stress Talk to your doctor about any medications you're taking. Improve your sleep. Try imagery rehearsal treatment.