Our review confirms the usefulness of long-term pharmacological treatments for PD and GAD and suggests that they can provide further improvement over that obtained during short-term therapy .
Paroxetine , escitalopram , and clonazepam can be effective for long-term treatment of PD .
Pregabalin and quetiapine can be effective for long-term treatment of GAD , while preliminary suggestions emerged for agomelatine and vortioxetine .
We did not find any evidence for determining the optimal length and /or dosage of medications to minimize the relapse risk .
Many aspects of long-term pharmacological treatments for  anxiety disorders ( AnxDs ) are still debated .
We undertook an up date d systematic review of long-term pharmacological studies on panic disorder ( PD ) , generalized anxiety disorder ( GAD ) , and social anxiety disorder ( SAD ) .
Time to relapse after 6 and 12 months' treatment of generalized anxiety disorder with venlafaxine extended release.
CONTEXT Generalized anxiety disorder ( GAD ) is a chronic disorder in need of reliable data to guide long-term treatment . OBJECTIVES To assess the benefits of 6 and 12 months ' treatment of GAD with venlafaxine hydrochloride extended release ( XR ) in patients who improved after 6 months ' open-label venlafaxine XR treatment . DESIGN After 6 months ' open-label venlafaxine XR treatment , improved patients were r and omized to venlafaxine XR or placebo for 6 months . All venlafaxine XR patients still in the study at 12 months were r and omized to receive venlafaxine XR or placebo , and all placebo patients continued taking placebo for another 6 months . SETTING One urban site ( 5 locations ) . PATIENTS Of 268 patients with a diagnosis of GAD entering the open-label venlafaxine XR treatment phase , 158 ( 59.0 % ) completed 6 months , and 136 ( 50.7 % ) entered relapse phase 2 ( 6 - 12 months ) . Fifty-nine ( 43.4 % ) of 136 patients entered phase 3 ( 12 - 18 months ) . INTERVENTION Six months ' open-label treatment with venlafaxine XR , followed by double-blind venlafaxine XR or placebo for 2 relapse phases , each lasting 6 months . MAIN OUTCOME MEASURES Time to relapse while receiving venlafaxine XR or placebo after 6 and after 12 months of treatment . Relapse was strictly defined to safeguard against assigning patients with venlafaxine XR discontinuation symptoms or temporary anxiety increase as relapse . RESULTS For objective 1 , relapse rates in phase 2 ( months 6 - 12 ) were 9.8 % on venlafaxine XR and 53.7 % on placebo ( P < .001 ) . For objective 2 , relapse rates after 12 months on placebo ( 32.4 % ) were lower than after 6 months on venlafaxine XR ( 53.7 % ) ( P < .03 ) . CONCLUSIONS Treatment of GAD with an antidepressant should be continued for at least 12 months . Preliminary data demonstrate that improved patients who relapse while off their antianxiety medication after at least 6 months of treatment will again most likely respond to a second course of treatment with the same medication . Trial Registration clinical trials.gov Identifier : NCT00183274
Our review confirms the usefulness of long-term pharmacological treatments for PD and GAD and suggests that they can provide further improvement over that obtained during short-term therapy .
Paroxetine , escitalopram , and clonazepam can be effective for long-term treatment of PD .
Pregabalin and quetiapine can be effective for long-term treatment of GAD , while preliminary suggestions emerged for agomelatine and vortioxetine .
We did not find any evidence for determining the optimal length and /or dosage of medications to minimize the relapse risk .
Many aspects of long-term pharmacological treatments for  anxiety disorders ( AnxDs ) are still debated .
We undertook an up date d systematic review of long-term pharmacological studies on panic disorder ( PD ) , generalized anxiety disorder ( GAD ) , and social anxiety disorder ( SAD ) .