Studying interictal behavioral and cognitive changes is complicated by the multiple variables that may be associated with epilepsy, such as:
- structural brain lesions (e.g., vascular lesions, tumors, scars), which may produce both behavioral symptoms and seizures
- the effects of antiepileptic drugs (AEDs)
- psychosocial effects, including isolation, stigmatization, dependence, inability to drive
In many people with epilepsy, interictal changes in personality do not develop. A distinct interictal behavioral syndrome associated with temporal lobe epilepsy (TLE) was first suggested in the English literature in the 1970s. The features of the syndrome are more appropriately described as behavioral changes than as a behavioral disorder, because some of the behaviors are not maladaptive or pathologic. One clinical feature is altered sexuality, usually in the form of hyposexuality. A confounding variable may be the effect of antiepileptic drugs (AEDs) on sexual functioning. However, hyposexuality has been reported to improve after adequate treatment with AEDs or temporal lobectomy. Rarely, hypersexuality or other altered sexual behaviors may develop.
Viscosity, another frequently described finding, refers to an interpersonal style marked by increased verbalization, circumstantiality, and difficulty shifting topics in conversation. Some suggest that subtle language impairment may play a role, but a tendency to develop intense personal relationships (social cohesiveness) may be more critical.
Other changes highlighted in the literature include increased religious beliefs and a heightened concern for morality. Religious and moral themes tend to predominate when patients display hypergraphia, an increase in the volume of written material the person produces and a preoccupation with details within the content. The association of these behaviors to epilepsy, including TLE, is controversial.
Since the publication of such reports, a number of authors have questioned the linking of these personality changes with TLE. Indeed, various authors have indicated that such changes are not specific to patients with epilepsy but are also identified in other neurologic disorders. Furthermore, a recent review pointed out that patients with frontal lobe epilepsy are more likely to present these personality changes than those with temporal lobe epilepsy.
Adapted from: Holzer JC and Bear DM. Psychiatric considerations in patients with epilepsy. In: Schachter SC, Schomer DL, eds. The comprehensive evaluation and treatment of epilepsy. San Diego, CA: Academic Press; 1997. p. 131-148. With permission from Elsevier (www.elsevier.com).