During depression a great deal of time and mental resource is given over to repetitive negative thinking. Once the process starts it can become so ingrained and persistent that it can become your reality. Conversely, the greater the distance you can put between yourself and depressed thinking the less trapped you will feel and the more your sense of control will improve. Changing your relationship with your thinking isn't something that comes easily to everyone but it can be surprisingly therapeutic.
Neutralizing negative thinking is not about trying to think happy thoughts. It's more about accepting the fact that you are thinking negatively but recognizing they are just thoughts and have no more substance than that. Thoughts do not require us to behave in certain ways nor do we have to believe in them, feel ourselves judged by them, or view the world from their perspective.
There are all kinds of available strategies to manage our worries. Something as simple as distraction through a pleasurable activity can be completely absorbing. Even thinking pleasurable or calming thoughts can evoke potent and relaxing sensations. Some people allow themselves 'worry time' where they allow themselves a set time frame (maybe 30 minutes) to ruminate before getting on with something else.
One particular set of techniques currently generating research interest is termed mindfulness-based approaches. Essentially these represent a fusion of ancient Buddhist practices with current psychological understanding. There may be some differences in approach but a common factor is the entirely pragmatic emphasis on stillness, breathing, and paying deliberate attention to our experiences from moment to moment without self-criticism.
At face value standing back from the feelings and bodily sensations that trouble us may not seem like an especially useful or effective strategy, but the evidence is fairly impressive. I'll be exploring mindfulness-based stress reduction and mindfulness-based cognitive therapy in later Shareposts.