The aims of the study were to: 1) assess the validity of the mood and anxiety modules of the PRIME-MD Patient Health Questionnaire (PHQ) in otorhinolaryngology outpatients consulting with dizziness; and, 2) the prevalence of anxiety and mood disorders in these patients and in 3 subgroups based on of the cause of dizziness (Functional group, with psychogenic or hyperventilation factor; Organic group with an organic cause; Unspecified group without indication of organic or psychogenic cause). The PRIME-MD PHQ was completed by 268 consecutive outpatients. In 97 patients a psychiatric interview was performed. Operating characteristics indicated good criterion validity for the assessed modules of the PRIME-MD PHQ. Thirty five percent of the patients were diagnosed with "Any Anxiety or Depressive Disorder". In the Functional group, the prevalence of "Any Anxiety or Depressive Disorder" was significantly higher than in the Organic group (P<.0001) and than in the Unspecified group (P<.0001). In the Unspecified group, the prevalence of "Any Anxiety or Depressive Disorder" was significantly lower than in the Organic group (P =.007). Our findings support the criterion validity of the PRIME-MD PHQ for anxiety and depressive disorders in otorhinolaryngology outpatients with dizziness. Psychiatric disorders were highly prevalent and differences in psychiatric status between the different subgroups were demonstrated.