Stringhalt to three years. Horses may be affected so severely that euthanasia is necessary. It is unknown how long it takes for clinical signs to develop after the exposure to the cause of the condition. The majority of horses affected by stringhalt are dependent upon pasture for nutrition. Removal of the horse from its original paddock containing low-quality pasture, weeds and native grasses, along with dietary control, was the most common and successful treatment. Lateral digital extensor tenectomy has also been used as a treatment by veterinarians with a success rate of just over 50%. Phenytoin has been used in the
Antisocial personality disorder the Factor 1 traits of psychopathy, which describes its core affective (e.g. lack of empathy, fearlessness) and interpersonal (e.g. grandiosity, manipulativeness) personality disturbances. This is suggestive of two different forms, one associated more with impulsive behavior and emotional dysregulation, and the other with predatory aggression and affective disturbance, of the disorder. Various other gene candidates for ASPD have been identified by a genome-wide association study published in 2016. Several of these gene candidates are shared with attention-deficit hyperactivity disorder, with which ASPD is comorbid. Traumatic events can lead to a disruption of the standard development of the central nervous system,