Rapid response of a disorder to the addition of lithium carbonate: panic resistant to tricyclic antidepressants

There is evidence that panic disorder and major depression might share some common neurobiological factors. This would be consistent with the fact that most antidepressant drugs are effective in preventing panic attacks. This is a case report of a 40 year old woman who was suffering from a panic disorder. Following the discontinuation of a long-term lorazepam treatment, she developed severe depressive symptoms. The depressive syndrome improved rapidly with amitriptyline (150 mg/day), but the panic attacks persisted. Twelve weeks later, amitriptyline was replaced by clomipramine (150 mg/day), the dosage of which was increased to 225 mg/day three weeks later. The patient remained anxious with no resolution of her panic attacks. Two weeks later, lithium carbonate (900 mg/day) was added to clomipramine. Sixty hours later, a dramatic improvement was observed. The lithium plasma level was 0.8 mEq/L. Because of some tremors, lithium was discontinued five days later. Within four days, the anxiety as well as the panic attacks reappeared. Lithium carbonate (600 mg/day) was then resumed. Forty-eight hours later, the patient was showing a clinical improvement similar to that observed following the first addition of lithium. She remained symptom free with the maintenance of the drug combination. To date, several reports have confirmed the beneficial effect of adding lithium to a tricyclic antidepressant drug in resistant major depression. However, we believe that the present case report is the first one documenting the augmentation of a tricyclic antidepressant drug by lithium in a patient suffering from a panic disorder.