Objective To improve treatment outcomes for patients with chronic dizziness by identifying clinical conditions associated with persistent symptoms and delineating key diagnostic features that differentiate its causes and direct attention to specific treatments.
Design Prospective cohort study from 1998 to 2004.
Setting Tertiary care balance center.
Patients A total of 345 men and women, aged 15 to 89 years, referred for evaluation of chronic dizziness (duration of 
3 months) of uncertain cause.
Interventions Patients were systematically directed through multiple specialty examinations until definitive diagnoses were made.
Main Outcome Measure Final diagnoses associated with dizziness.
Results Nearly all patients with chronic subjective dizziness were diagnosed with psychiatric or neurologic illnesses. These included primary and secondary anxiety disorders (n = 206 [59.7%]) and central nervous system conditions (n = 133 [38.6%]), specifically migraine headaches, mild traumatic brain injuries, and neurally mediated dysautonomias. A small number of patients (6 [1.7%]) had dysrhythmias. Four of 5 patients with migraine or dysrhythmias had comorbid anxiety.
Conclusions Chronic dizziness has several common causes, including anxiety disorders, migraine, traumatic brain injuries, and dysautonomia, that require different treatments. Key features of the clinical history distinguish these illnesses from one another and from active neurotologic conditions. The high prevalence of secondary anxiety may give a false impression of psychogenicity.
