Antidepressants in panic disorder

Panic disorder is a serious and common illness affecting 1% of the population at any one time. Comorbidity with depression may be as high as 40%. The illness has been recognized as a separate entity since the 1960s and treatment with tricyclics being used since that time. Tricyclics, monoamine oxidase inhibitors, benzodiazepines, beta-blockers and anticonvulsants have all been used with varying degrees of success. Until recently, tricyclics and benzodiazepines were the treatments of choice but selective serotonin reuptake inhibitors (SSRIs) have recently been studied intensively and, based on studies of citalopram and paroxetine, must now be considered first line therapy. Both SSRIs and tricyclics suffer from a long latency period, possibly as long as 12 weeks before maximal benefit is obtained, which is in contrast to the benzodiazepines that produce almost instant symptom relief. The dependency potential of the benzodiazepines, however, limits their usefulness. Paroxetine and citalopram have good efficacy data over both the short and long term and are effective at standard dosages, the most effective for citalopram being 20-30 mg. Both drugs performed better than the comparator tricyclic antidepressant (chlomipramine) and must now be considered current drugs of choice. Despite the superior efficacy of these drugs, however, many patients are poorly controlled and investigation of combination therapies for resistant panic disorder is needed.