This is a direct quote from Lundy Bancroft which I've copied and pasted from the Abuser Profiles thread:
THE MENTALLY ILL OR ADDICTED ABUSER
This last category is not actually separate from the others; an abusive man of any of the aforementioned styles can also have psychiatric or substance-abuse problems, although the majority do not. Even when mental illness or addiction is a factor, it is not the cause of a man's abuse of his partner, but it can contribute to the severity of his problem and his resistance to change. When these additional problems are present, it is important to be aware of the following points:
- Certain mental illnesses can increase the chance that an abuser will be dangerous and use physical violence. These include paranoia, severe depression, delusions or hallucinations (psychosis), obsessive-compulsive disorder, and antisocial personality disorder known as psychopathy or sociopathy). These psychiatric conditions also make it next to impossible for an abuser to change, at least until the mental illness has been brought under control through therapy and/or medication, which can take years. Even if the mental illness is properly treated, his abusiveness won't necessarily change.
- An abuser's reactions to going on or off medication are unpredictable. A woman should take extra precautions for her safety at such a time. Abusers tend to go off medication before long—I have had few clients who were consistent and responsible about taking their meds in the long term. They don't like the side effects, and they are too selfish to care about the implications of the mental illness for their partners or children.
- The potential danger of a mentally ill abuser has to be assessed by looking at the severity of his psychiatric symptoms in combination with the severity of his abuse characteristics. Looking at his psychiatric symptoms alone can lead to underestimating how dangerous he is.
- Antisocial personality disorder is present in only a small percentage of abusers but can be important. Those who suffer from this condition lack a conscience and thus are repeatedly involved in behaviors that are harmful to others. Some signs of this condition include: (a) He started getting into illegal behavior when he was still a teenager; (b) his dishonest or aggressive behavior involves situations unrelated to his partner, rather than being restricted to her; (c) he periodically gets into trouble at workplaces or in other contexts for stealing, threatening, or refusing to follow instructions and is likely to have a considerable criminal record by about age thirty, though the offenses may be largely minor ones; (d) he is severely and chronically irresponsible in a way that disrupts the lives of others or creates danger; and (e) he tends to cheat on women a lot, turn them against each other, and maintain shallow relationships with them. The psychopath's physical violence is not necessarily severe, contrary to the popular image, but he may be very dangerous nonetheless. Antisocial personality disorder is very difficult to change through therapy, and there is no effective medication for treating it. It is highly compatible with abusiveness toward women.
- Those who suffer from narcissistic personality disorder have a highly distorted self-image. They are unable to accept that they might have faults and therefore are unable to imagine how other people perceive them. This condition is highly compatible with abusiveness, though it is present in only a small percentage of abusive men. Clues to the presence of this disorder include: (a) Your partner's self-centeredness is severe, and it carries over into situations that don't involve you; (b) he seems to relate everything back to himself; and (c) he is outraged whenever anyone criticizes him and is incapable of considering that he could ever be anything other than kind and generous. This disorder is highly resistant to therapy and is not treatable with medication. The abuser with this disorder is not able to change substantially through an abuser program either, although he sometimes makes some minor improvements.
- Many abusers who are not mentally ill want women to think that they are, in order to avoid responsibility for their attitudes and behavior.
Substance abuse, like mental illness, does not cause partner abuse but can increase the risk of violence. Like the mentally ill abuser, the addicted abuser doesn't change unless he deals with his addiction, and even that is only the first step. Chapter 8 examines the role that substances play in partner abuse.
The attitudes driving the mentally ill or addicted batterer are the same as those of other abusers and will likely follow the pattern of one of the nine styles described above. In addition, the following attitudes tend to be present:
• I am not responsible for my actions because of my psychological or substance problems.
• If you challenge me about my abusiveness, you are being mean to me, considering these other problems I have. It also shows that you don't understand my other problems.
• I'm not abusive, I'm just———(alcoholic, drug addicted, manic-depressive, an adult child of alcoholics, or whatever his condition may be).
• If you challenge me, it will trigger my addiction or mental illness, and you'll be responsible for what I do.
Although I have focused on the emotionally abusive styles of these different kinds of abusers, any of them may also use physical violence, including sexual assault. Although the Terrorist and the Drill Sergeant are especially likely to become dangerous, they are not the only ones who may do so. Many abusers occasionally use physical violence or threats as a way to intimidate you when they feel that their power or control over you is slipping; violence for them is a kind of trump card they use when their normal patterns of psychological abuse are not getting them the degree of control they feel entitled to. If you are concerned about how dangerous your partner may be, see Is He Going to Get Violent? in Chapter 6 and Leaving an Abuser Safely in Chapter 9.