Anosognosia is common in people with a mental illness and can indicate a serious illness, such as schizophrenia or bipolar disorder. In this case, the patient does not realize that he is sick, and actively protests against the treatment prescribed to him. People with mental pathologies usually develop a total rejection of their disease state without a system of evidence. Anosognosia in patients develops most often under the influence of the following factors:
- progressive decline in intelligence and other mental functions, especially memory impairment (amnesia, dementia);
- acute psychosis with disorganization of consciousness, inability to critically evaluate and generally rational thinking;
- hysterical psychosis;
- autopsychic disorientation in chronic psychosis;
- all-consuming indifference (apathy);
- stunning consciousness of any depth, since higher nervous activity suffers.
Anosognosia often develops in chronic alcoholics and drug addicts, they do not want to consider themselves sick, ignore the symptoms and refuse treatment. Most psychiatrists attribute this phenomenon in narcological patients to a defensive reaction to information about the occurrence of persistent addiction, since recognition of this fact is detrimental to the patient’s self-esteem, and some researchers attribute the inability of alcoholics (drug addicts) to critical self-perception with unconscious activation of protective repression (denial) of guilt.
According to K. Jaspers, anosognosia in alcoholics and drug addicts is based on their pathological self-perception. Narcological patients have a special personality warehouse, their nature is characterized by a pathological attraction to the use of psychoactive substances. Most alcoholics and drug addicts rarely recognize themselves as ill and do not notice symptoms of the development of pathological alcoholization (anesthesia), especially mental ones. This contingent has a disposition only to receive the next dose of alcohol or a drug, the harm of which is well known, and addiction to them is considered a vice. Anosognosia allows you to mask the perception of dependence and not be afraid of the consequences, with prolonged abuse, an organic psychosyndrome develops and a mental disorder develops on this basis. 
Rejection of one’s disease also develops in patients with damage to the central nervous system of various origins. Risk factors: traumatic brain injuries, infections, intoxications, in particular, carbon monoxide or mercury, hypoxia, ischemia, strokes, progressive atherosclerosis. Depending on the localization of the lesion focus, patients with a completely preserved ability to navigate in a real situation do not recognize their physical disabilities, blindness or deafness, believe that their paralyzed limbs move, and so on.
In somatic and somatopsychic patients, anosognosia is observed as a debut symptom of such diseases as cancer, AIDS, tuberculosis, hepatitis, peptic ulcer, arterial hypertension. In these cases, some researchers consider the anosognosic type of attitude toward the disease necessary to maintain psychological health.