If a person is depressed, it will usually affect his or her appetite (too little or too much food), sleeping patterns (often too much), libido, self-esteem, level of motivation, energy, feelings of guilt, fear of the future, and could lead to thoughts of suicide.
While medications, such as SSRIs (e.g. Celexa) are effective at reducing depressive symptoms, their effectiveness is incumbant on the persons continued use of them - stop using your meds, the depression often returns because the psychological reasons that led to the depression are often still active.
Cognitive behaviour therapy (CBT) has been shown to be at least as effective as medications in treating depression and offers the added benefit that the results can continue after therapy stops.
Here are some strategies to manage your depression:
1) You need to engage with life. When people are depressed, they typically have low energy and subsequently lack the motivation to engage with activities that used to be fulfilling and enjoyable. This leads the individual to winnow their world down to several mundane tasks without anything positive or rewarding.
One of the most important strategies is called behavioural activation. This essentially means that you need to choose several activities that used to bring you happiness and start engaging in them. For example, if you used to enjoy exercising or you had creative pursuits, start with those and slowly add more activities to your schedule. There is a belief among those who are depressed that you need motivation before you do something but motivation can actually follow behaviour. Forcing yourself to do something fun will eventually lead you to be motivated to continue with the activity.
2) Start slow. One of the most common mistakes I see with those suffering from depression is an expectation that they should be just as productive as they were when they were not depressed. I will hear statements such as, "I used to be able to study for 5 hours straight but now I can barely remember a single paragraph of what I've just read." Well, of course not, you are depressed!
If you had cancer and found your energy level depleted, you would not be critical of your lowered productivity but people do not equate mental health issues with physical health issues but they should.
If you are trying to reengage with exercise, begin slowly. Even if you used to go to the gym for 1 hour, three times a week, start with a goal of doing 15 minutes of exercise. When you are done, praise yourself because what you just accomplished was hard. Slowly build how much you do but be mindful not to be critical of yourself - recognize that you are going through a hard time and be gentle.
3) Don't judge your depression. I sometimes hear clients say, "I get angry at myself when I am depressed." This makes no sense and only makes things worse for you because you are judging yourself for something beyond your control. Nobody chooses to be depressed, it is something people suffer with. If you are depressed, accept it ("I am feeling depressed these days and I accept that"), and be kind to yourself. This means that you change your expectations for how much you can accomplish and you engage in self-care activities like a warm bath, soothing tea, reading a book or magazine and saying kind things to yourself.
4) Reach out to family and friends (and a therapist if necessary). People who are depressed tend to isolate themselves, exacerbating their low mood because they now also feel lonely and like a burden. Tell your friends and family what you are going through. Don't be dismissive of it. If you think you are being a burden, tell that to your friends and see what they say. It is highly likely that they will thank you for opening up to them and it could lead them to tell you about their own struggles with a mental health issue. If you are finding that you are having suicidal thoughts or that it is difficult to get things done in your life, consider contacting a therapist to get support.
5) Pay attention to your negative, maladaptive thoughts. Depression can lead distorted ways of thinking about yourself or your future. Thoughts such as, "Nothing is going to change" or "Nobody cares about me" are perpetuating your depression. It is important to become aware of these kinds of thoughts and challenge them. Ask yourself, with this thought, am I predicting the future, am I engaging in all-or-nothing thinking, am I catastrophizing? Strive to develop realistic thinking and keep repeating it. For example, the original thought of ,"Things are never going to change" could become "Things are difficult now because I am depressed but this is likely temporary - what can I do right now to feel a little better?"
6) Here is the classic book on depression:
Some more depression management strategies can be found here