OPD is associated with a large variety of symptoms, such as deficits in cognitive function, dysfunctional/abnormal behaviour, psychosis, neurosis, higher irritability and altered emotional expression.
In addition, patients may show a reduction in ability of perseverance with goals and they disinhibition, often characterised by inappropriate sexual and antisocial behavior.
The most common reason for this profound change in personality is the traumatic brain injury.
[citation needed] OPD may also be caused by lesions in other circumscribed brain areas.
This personality disturbance must be explainable directly as a result from a pathophysiological health condition affecting the brain.
There are seven sub-classifications of secondary personality change based on disturbances of affect, which includes "constricted", "blunted", "flat", "labile" and "inappropriate", along with other specified and unspecified categories.
It is characterized by "a significant alteration of the habitual patterns of behaviour displayed by the subject premorbidly, involving the expression of emotions, needs and impulses.
The symptom of epileptic seizure has influence on patients' personality that means it causes behavioural alterations.
[6] Patients with OPD show a wide variety of sudden behavioural changes and dysfunctions.
However, the choice of drug therapy relies on the seriousness of patient's situation and what symptoms are shown.
For this reason, it is crucial for patients' treatment to be assessed by clinical psychologists and psychiatrists before the administration of drugs.