When taking sertraline for anxiety or depression it can take between 1 to 2 weeks for the Sertraline to work for anxiety and depression after taking it.
The Sertraline usually works on depression and anxiety within the first two weeks of treatment, and the improvement continues over the following few weeks.
However for full effects it can take up to 4 weeks to see the full effects of the sertraline to take affect but you should notice results within a few weeks of taking it.
If you don't notice any results or much results after 4 weeks of taking the sertraline then speak with your doctor because they may need to up your dosage.
But don't simply up your dosage of the Sertraline until you speak with your doctor first.