The panic disorder respiratory ratio: a dimensional approach to the respiratory subtype

OBJECTIVE: The respiratory ratio is a dimensional construct of the respiratory subtype of panic disorder (PD). The respiratory subtype has been correlated with an increased sensitivity to CO2 inhalation, positive family history of PD and low comorbidity with depression. The objective of our study was to determine whether the respiratory ratio is correlated with CO2-induced panic attacks and other clinical and demographic features. METHODS: We examined 91 patients with PD and submitted them to a double-breath 35% CO2 challenge test. The respiratory ratio was calculated based on the Diagnostic Symptom Questionnaire (DSQ) scores recorded in a diary in the days preceding the CO2 challenge. The scores of the respiratory symptoms were summed and divided by the total DSQ score. RESULTS: The respiratory ratio was correlated with CO2 sensitivity, and there was a non-statistically significant trend towards a correlation with a family history of PD. CONCLUSIONS: The positive correlation between the respiratory ratio and the anxiety elicited by the CO2 inhalation indicates that the intensity of respiratory symptoms may be proportional to the sensitivity to carbon dioxide.

Imipramine for vestibular dysfunction in panic disorder: a prospective case series / Imipramina para disfunção vestibular em transtorno do pânico: uma série de casos prospectiva

OBJECTIVE: The purpose of this study was to evaluate the efficacy and effectiveness of imipramine on the treatment of comorbid chronic dizziness and panic disorder. METHOD: Nine patients with panic disorder and agoraphobia associated with chronic dizziness underwent otoneurological screening and were treated with a 3-months course of imipramine. Anxiety levels were measured with the Hamilton Anxiety Scale (HAM-A), dizziness levels were evaluated using the Dizziness Handicap Inventory (DHI), and panic severity and treatment outcome were assessed with the Clinical Global Impression Scale (CGI). RESULTS: At the baseline 33.3 percent (n=3) had a bilateral peripheral deficit vestibulopathy, the mean scores for HAM-A were 27.2±10.4, for DHI were 51.7±22.7, and for CGI-S were 4.8±0.9. All patients had a significant reduction in their HAM-A (11.1±5.5, p=0.008), DHI (11.5±8.1, p=0.008) and CGI-I (1.8±0.7, p=0.011) levels after 3-months imipramine treatment (mean=72.2±23.2 mg/day). CONCLUSION: This study found a decrease in anxiety levels and in the impact of dizziness in the patients' quality of life after a 3-months treatment course with imipramine.

OBJETIVO: O objetivo deste estudo foi avaliar a eficácia e efetividade da imipramina no tratamento da tontura crônica e do transtorno de pânico comórbidos. MÉTODO: Nove pacientes com transtorno do pânico e agorafobia associada com tontura crônica foram submetidos à avaliação otoneurológica e tratados durante 3 meses com imipramina. Os níveis de ansiedade foram medidos através da Escala Hamilton de Ansiedade (HAM-A); os de tontura foram avaliados usando o Dizziness Handicap Inventory (DHI), e a gravidade do pânico e sua resposta pela Escala de Impressão Clínica Global (CGI). RESULTADOS: Na avaliação inicial, 33,3 por cento (n=3) da amostra apresentavam vestibulopatia periférica deficitária bilateral; as médias foram: da HAM-A 27,2±10,4, do DHI 51,7±22,7 e do CGI-S 4,8±0,9. Todos tiveram uma redução significativa nos escores de HAM-A (11,1±5,5, p=0,008), DHI (11,5±8,1, p=0,008) e CGI-I (1,8±0,7, p=0,011), após 3 meses de tratamento com imipramina (média=72,2±23,2 mg/dia). CONCLUSÃO: Este estudo encontrou uma diminuição dos níveis de ansiedade e do impacto da tontura na qualidade de vida dos pacientes após um curso de 3 meses de tratamento com imipramina.