Treatment-Resistant Depression in Real-World Clinical Practice: A Systematic Literature Review of Data from 2012 to 2022.

Many people continue to experience depression even after trying two or more medications. This is called treatment-resistant depression (TRD). Most of the information we have on TRD comes from clinical trials, which take place under tightly-controlled conditions. It is important to understand the effects of TRD and TRD treatments on people in their day-to-day lives. Researchers studying people's day-to-day lives call this researching in a "real-world setting". We searched for studies carried out in real-world settings in the last 10 years. We found 20 relevant studies. As these studies were in real-world settings, there were many differences between them, including differences in how TRD was diagnosed, the treatments used, how long people were monitored and how results were measured. This made it difficult to compare how successful different treatments were. Most studies included a small number of people and monitored them for a relatively short time. We found people with TRD had usually lived with it for many years and their symptoms were moderate or severe. Only two studies asked people how TRD affected their lives. These two studies found health-related quality of life and work productivity was low. Most studies found lots of people still had symptoms of depression after treatment. However, symptoms typically improved more when studies monitored people for a longer time. To improve our knowledge of TRD, future studies should monitor more people for longer and use the same ways of measuring results. They should also ask how TRD affects people's daily lives.