How fast are antidepressants?

BACKGROUND: For years, investigators have tried to determine the speed of onset of antidepressant drugs. Claims that particular drugs may produce a faster response in patients than other agents have been made, but such claims have never been confirmed.
METHOD: The authors reviewed reports from studies of the speed of onset of antidepressant therapies and other studies that revealed information on this topic. We compiled a list of factors that can affect the results of such studies and interpretations of study results. In addition, we reviewed literature concerned with methods of speeding up antidepressant responses.
RESULTS: No antidepressant medication currently available has been shown conclusively to have a more rapid onset of action than any other. However, some methods of augmentation may have the potential to speed responses. Somatic therapies such as electroconvulsive therapy, phototherapy, and therapeutic sleep deprivation may be the fastest options available at this time.
CONCLUSION: All available antidepressant medications are usually taken for several weeks before future responders will display a significant therapeutic benefit. If a patient does not show at least a 20% improvement within the first 2 to 4 weeks of treatment, the treatment regimen should be altered. For patients who do show early benefits from a medication trial, one can expect additional benefits to accrue over an 8- to 12-week period and to improve overall outcome compared with those slower to respond. Future trials need to address methodological confounds, but a truly "faster antidepressant" will probably require new neuroscience technology.