The dopamine side(s) of depression

Depression is a disease with a difficult set of symptoms. Not only are the symptoms difficult to describe (how do you really describe anhedonia, before you know the word for it?), symptoms of depression manifest in different ways for different people. One person will eat more, sleep all the time, move slowly. Another will eat almost nothing, never sleep, and be irritable and nervous. They are both depressed. The only universal symptom is the feeling of...depression, and the need for successful treatment. Treatments which often take several weeks to work, are often ineffective, and which come with a host of side effects.So I was particularly intrigued when Nature published two papers this week looking at the role of dopamine in depressive-like behavior. What I particularly like is that these two papers have somewhat opposite results, due to different behavioral methods, something which I think highlights some of the problems associated with studying depression. Ed Yong covered both of the studies together fabulously over at Not Exactly Rocket Science , but I'd like to look at them both separately, to take a deeper look at each one, see what they've achieved, and what other questions they raise. So I will start with one today, and post the other tomorrow, looking at both sides of dopamine's potential role in depression. [More]