Depression affects how a person feels, how they thing about things, their energy levels, their concentration, their sleep.  It has an effect on many aspects of a person's live.

It affects their motivation to do things.  They can feel lethargic and experience a loss of energy and interest - nothing seems worth doing, everything seems pointless.  Each day can be extremely difficult and challenging and may mean that they have the sense that they have to force themselves to perform even the most minor of activities. 

They can experience an increase in negative emotions, especially anger.  They might become extremely irritable, snappy at family and friends.  They may then feel guilty about this and this makes them more depressed.  

Other very common symptoms are anxiety and fear.  When we are depressed we feel we can feel extremely vulnerable.  Things that we may have done easily before seem frightening.

Other negative feelings that can increase in depression are sadness, guilt, shame, envy and jealousy.

Depression interferes with the way we think in two ways.  It affects concentration and memory.  We find that we cannot focus on anything.  Reading a book or watching TV can become impossible.  It is easier to remember negative things than positive ones.  It also affects our thoughts in the way that we think about ourselves, our future and the world.  Very few people who are depressed feel good about themselves and they generally tend to see themselves as inferior, flawed, bad or worthless.

Behaviours change when we become depressed.  We engage in much less positive actvity and may withdraw socially and want to hide way.  Since everything seems to take so much effort, we do much less than we used too.  We tend to do fewer positive things with others and are more likely to find ourselves in conflict with them  If we become very anxious, we might also start to avoid meeting people or lose our social confidence.

Depressed people sometimes become agitated and find it extremely difficult to relax.  Sometimes the desire to escape and run away can be very strong but where to go and what to do is unclear.