DEVELOPMENTS IN THE DRUG-TREATMENT OF PANIC DISORDER - WHAT IS THE PLACE OF THE SELECTIVE SEROTONIN REUPTAKE INHIBITORS

Panic disorder is becoming better recognised and understood as a chron ic, debilitating but treatable condition. Drug treatment options shown by adequate research to be beneficial in this condition include mainl y the benzodiazepine alprazolam, the tricyclic antidepressants (TCAs) imipramine and clomipramine, the monoamine oxidase inhibitor (MAOI) ph enelzine, and the newer selective serotonin reuptake inhibitors (SSRIs ) fluvoxamine and paroxetine. Alprazolam, although approved for use in panic disorder in the US and very widely used, is associated with a r isk of dependence and withdrawal syndromes. Given that depression freq uently occurs as a comorbid condition with panic disorder the use of a ntidepressants is a logical choice. Among the antidepressants, MAOIs a re little-used in panic disorder, mainly because of their potential fo r precipitating hypertensive crises if tyramine is ingested. TCAs are widely used and are effective but they are associated with initial act ivation, or 'jitteriness', have a 4-6-week time lag before onset of be neficial effect and produce troublesome side effects in a high proport ion of patients, particularly during long-term use. TCAs are also card iotoxic in overdosage, and panic disorder patients with comorbid depre ssion are at high risk of attempted suicide. Serotonin dysregulation h as been implicated in the pathogenesis of anxiety disorders in general , and panic disorder in particular. Among the TCAs, those with an effe ct on serotonin reuptake are most effective in panic disorder. SSRIs a re specifically active on serotonin reuptake and do not have anticholi nergic effects or act on the noradrenergic system. There is a clear ph armacological rationale for believing that SSRIs should be as effectiv e as TCAs in panic disorder and better tolerated. Accumulating clinica l research evidence supports this hypothesis. Further comparative stud ies with standard agents and additional long-term studies to support t he initial long-term data with paroxetine are needed to confirm SSRIs as drug treatment of choice in panic disorder.