Depression represents a huge pharmaceutical market opportunity. There are 
approximately 350 million people worldwide with depression, and it is the 
leading cause of disability in the world. In the U.S., 9.1% of the population 
suffers from depression. Globally, fewer than half of depression sufferers 
receive treatment for their illness, and in some countries this figure falls to 
fewer than 1 in 10. The high incidence rate, combined with limited market 
penetration, makes depression a high potential market for pharmaceuticals. 
However, companies developing drugs for depression also face a number of serious 
challenges. Psychosocial treatment options remain the preferred first-line 
therapy ahead of medication-and when it comes to drug treatment, the abundance 
of generic options available has significantly contributed to halving the value 
of the branded antidepressant market over recent years. Another hurdle faced by 
new drugs is the requirement that all antidepressants carry a black-box warning 
regarding the increased risk of suicide in children, adolescents and young 
adults, which limits their use in this population. Switching between medications 
presents both an opportunity and a challenge, as a significant number of 
patients will switch away from their first medication within the first year of 
treatment. The lack of complete understanding of why depression occurs also 
makes this area a difficult one, although it opens the door for the development 
of drugs with novel mechanisms of action.