Key considerations for long-term studies with anxiolytics

Long-term (minimum six months) safety and efficacy studies with an anti-anxiety agent are aimed at identifying the emergence of any clinical effects not observed during shorter periods of treatment including the identification of late occurring adverse events, loss of therapeutic benefit, or post-treatment withdrawal effects. There is the need to establish diagnostic criteria for persistent anxiety for patients who truly benefit from long-term therapy. Risk factors predisposing to drug dependence should be assessed prior to continuous use. Ideally, long-term continuous studies should be blinded, comparative and placebo-controlled, with an adequate duration of the withdrawal phase. The treatment response of the elderly in comparison to the overall patient sample should be emphasised.