There are no medications specifically approved for the treatment of personality disorders. However, there are several medications that may help with certain traits or co-morbid conditions.
Antidepressants are possibly the most widely prescribed medications for those with personality disorders. As the name suggests, they help to alleviate feelings of depression. They can also be useful for long-term treatment of anxiety, or for difficulty sleeping. There are several different types of antidepressants, and many people find that they need to try more than one antidepressant before they find the right one for them.
Antipsychotics are prescribed for several reasons. They are often prescribed when a person becomes psychotic (i.e. loses their grasp on reality in some way). However, they may be prescribed when a person has no psychotic symptoms. As some of them can be quite sedating, they are used to treat impulsivity and aggression as well as difficulty sleeping. They tend to have more side effects than antidepressants, although newer antipsychotics have less side effects than older ones. Antipsychotics are sometimes prescribed as mood stabilisers (which will be discussed next), although this is not usually their main purpose.
Mood stabilisers are used for extreme mood swings, particularly for those who have manic episodes. Most mood stabilisers are anticonvulsant medications that are also used to treat epilepsy. While these have very few side effects for many people, several of them require regular blood tests to check they're not causing damage to the body. Lithium is also often used as a mood stabiliser. This is a salt naturally produced in the body, but adjusting the level of it can sometimes help regulate mood. However, high levels of lithium can be very dangerous, so it requires close monitoring and blood tests.
Benzodiazepines are sometimes used as a short-term treatment for anxiety or difficulty sleeping. They take effect within minutes, so they're very effective. However, they are highly addictive, so many doctors are reluctant to prescribe them. Stopping benzodiazepines can also result in withdrawal or worsening of original symptoms.
Nonbenzodiazepines are used for difficulty sleeping. They act in a similar way to some benzodiazepines, but tend to be more sedating. They are slightly less addictive than benzodiazepines, but still carry a risk of addiction, especially if taken for more than a few weeks.
Antihistamines are commonly prescribed for allergies, but some are sedating enough to be used to help people sleep. They have little potential for addiction. However, tolerance to them builds up very quickly, so they are often only effective as a short-term treatment.
Stimulant medications are used to treat attention deficit disorder symptoms, and also for some types of depression. They are often addictive, particularly if used for long periods of time, so many doctors only prescribe them after trying other medications.