Yes, the cyst can cause depression if it grows big enough to 'squeeze' certain brain regions. In my case, with severe hydrocephalus, several areas of my brain were affected. There are symptoms with the hydrocephalus, and symptoms as it goes away. Both are important. The brain accommodates he cyst, and then it must accommodate again after the cyst is removed. The degree to which a person is affected relies on many factors. We all have certain levels of resilience and/or reserve. This is an area of intensive research.