Psychiatric Comorbidity and Hostility in Patients with Psychogenic Nonepileptic Seizures Compared with Somatoform Disorders and Healthy Controls *Kjell Mökleby, *Svein Blomhoff, *Ulrik Fr. Malt, *Astri Dahlström, †Erik Tauböll, and †Leif Gjerstad Departments of *Psychosomatic and Behavioral Medicine and †Neurology, Rikshospitalet, University of Oslo, Oslo, Norway Summary: Purpose: To investigate the prevalence of psychi- atric comorbidity and level of anxiety, depression, and aggres- sion in patients with psychogenic nonepileptic seizures compared with those in patients with somatoform disorders and healthy controls. Methods: Twenty-three patients with psychogenic nonepi- leptic seizures (PNESs) and 23 age- and sex-matched patients with somatoform disorders (SDs) underwent a clinical and a semistructured psychiatric interview (MINI) and filled in the Hospital Anxiety and Depression scale (HAD) and the Aggres- sion Questionnaire (AQ). Twenty-three sex- and age-matched controls without psychopathology also underwent a clinical in- terview and completed the HAD and AQ. Results: PNES reported more minor head injuries in the past than did the two comparison groups, and more unspecific EEG dysrhythmias were observed on EEG. Twenty-one PNES pa- tients and 18 with SDs had comorbid psychiatric diagnoses. However, the mean number of comorbid psychiatric diagnoses was higher in the PNES group (1.9 ± 0.3 compared with 1.5 ± 0.5 in the SD group; p  0.003). Ten PNES patients addition- ally had a somatoform pain disorder, and seven had an undif- ferentiated somatoform disorder. Both patient groups reported significantly higher levels of anxiety, depression, and anger than did the healthy controls, but the PNES patients had sig- nificantly higher level of hostility than both comparison groups. Conclusions: Increased psychiatric comorbidity is known to be associated with poorer response to regular interventions, and hostility is associated with more hostile coping patterns, often interfering with treatment compliance. Thus the in- creased prevalence of soft neurologic signs and comorbid psychiatric disorders and increased hostility as well in the PNES group, emphasizes that assessment and treatment of pa- tients with PNES referred to a tertiary center requires an inte- grated approach involving both neurologic and psychiatric resources. Key Words: Epilepsy—Psychogenic nonepileptic seizures (PNESs)—Somatoform disorder (SD)—Psychiatric comorbidity—Depression—PTSD—Hostility. The incidence of psychogenic nonepileptic seizures (PNESs) has been estimated to be 3.03–4.6 per 100.000 subjects (1). In contrast, between 10 and 20% of patients referred to epilepsy centers have PNESs, thus constitut- ing a major differential diagnosis for epileptic seizures (2,3). The disorder is frequently of long duration, and there is no general agreement on the best treatment (4–6). Accordingly, we need studies exploring the role of per- sonality and psychiatric disorders in PNES. So far, most studies have focused on a narrow range of comorbid psychopathology [i.e., anxiety and depression (7,8)]. The most common disorders reported to occur with PNESs are posttraumatic stress disorder (PTSD), panic disorder with or without agoraphobia, and affective disorders (9– 11). However, similar findings have been reported in somatoform disorders and depression, questioning the specificity of these findings relating PNESs to specific psychiatric disorders. Some studies have suggested that aggression and stress-related emotions such as anxiety and depression might be related to PNESs (12–14). However, our knowledge on this topic is hampered by the fact that the number of studies in this field has been few (11). In some studies, no control group was added, and comparison groups of other diagnostic groups known to be associated with anxiety, depression, and aggression were not in- cluded. Furthermore, neurologic or psychiatric diagnos- tic criteria have not been adequately assessed through structured methods. To overcome these limitations in our knowledge, we selected PNES patients based on strict neurologic criteria (PNES group). Second, we characterized all patients by the use of structured psychiatric interviews that defined diagnoses according to Diagnostic and Statistical Manual of Psychiatric Disorders, Version IV (DSM-IV) criteria (15). Third, the PNES group was compared with Revision accepted December 17, 2001. Address correspondence and reprint requests to Dr. K. Mökleby at Department of Psychosomatic and Behavioral Medicine, Rikshospita- let, N-0027 Oslo, Norway. E-mail: kjell.mokleby@rikshospitalet.no Epilepsia, 43(2):193–198, 2002 Blackwell Publishing, Inc. © International League Against Epilepsy 193