Background and Objectives Psychiatric disease is a frequent co-morbidity in idiopathic intracranial hypertension (IIH) and has been associated with a poor subjective outcome. No prospective studies have investigated psychiatric co-morbidities in new-onset IIH. Our primary aim was to investigate disease severity in IIH depending on co-morbid psychiatric disease. Important secondary outcomes were disease severity after 6-months and prevalence of psychiatric diseases in IIH. Methods This prospective, observational cohort study consecutively included patients with clinically suspected, new-onset IIH from two headache centers. A standardized diagnostic work-up was completed to confirm or exclude IIH according to the revised Friedman criteria: semi-structured interview, neurological and neuro-ophthalmological exam, lumbar puncture with opening pressure, neuroimaging. Exclusion criteria were known IIH, secondary intracranial hypertension, missing data, pregnancy. Disease severity was evaluated based on papilledema, visual fields, opening pressure and headache in IIH patients without psychiatric disease (IIH-P) compared to IIH patients with psychiatric disease (IIH+P). A blinded neuro-ophthalmologist assessed visual outcomes. Age- and sex matched prevalence rates of psychiatric diseases in the general population were found in national reports. Results 258 patients were screened, 69 were excluded. 189 patients with clinically suspected IIH were then evaluated with the diagnostic work-up, and IIH was confirmed in 111 patients (58.7%). 45% of IIH patients had a psychiatric co-morbidity. Visual fields were worse in patients with IIH+P at baseline (-8.0 versus -6.0 dB, p = 0.04) and after 6 months (-5.5 versus -4.0 dB, p < 0.01) compared to IIH-P. Highly prevalent psychiatric disorders were major depressive disorder (24.3%, n = 27), anxiety or stress-related disorders (24.3%, n=27) and emotionally unstable personality disorder (6.3%, n=7). Substance abuse (1.8%), schizophrenia (0.9%) and bipolar disorder (0.9%) were rare. In the general population prevalence estimates of major depressive disorder and emotionally unstable personality disorder were 1.8-3.3% and 2% respectively. Discussion Visual fields were significantly worse at baseline and 6 months in IIH+P compared to IIH-P. Psychiatric co-morbidities, particularly depression and emotionally unstable personality disorder, were highly prevalent in IIH. Increased awareness of psychiatric disease as a marker for worse visual status may improve patient care.

The diagnosis and management of idiopathic intracranial hypertension (IIH) can be difficult and multiple medical subspecialities are often involved. Several national and international guidelines regarding the investigations and management of IIH have been published in recent years but still there is no consensus about the optimal organization of IIH-care. The objective of this review was to propose and describe a referral pathway and an organization scheme for diagnosis and management of IIH. An extensive search of existing literature was conducted and summarized. In total, 237 IIH-articles were identified and hereof 43 included. The clinical practice in our specialized IIH-clinic is characterized and described. We conclude that an educational campaign involving medical care providers and patients with chronic headaches is necessary. A detailed organizational proposal for a referral pathway and management of IIH patients based on the literature search and our clinical experience from a highly specialized IIH outpatient clinic is suggested and discussed.