Anxiety disorders show a tendency to become chronic. Behavioral treatment and pharmacotherapeutic measures must frequently be applied over a lengthy period of time. The most suitable drugs for long-term treatment are the selective serotonin reuptake inhibitors (SSRI) and the serotonin norepinephrine reuptake inhibitor (SNRI), venlafaxine. With regard to side effects, the specific characteristics of the anti-anxiety drugs used for long-term therapy must be taken into account.