Teenage mood swings
On top of the world in the morning, depressed over lunch time and angry in the evening - teenagers have a reputation for mood swings.
Any rapid fluctuation in hormones is usually accompanied by irritability, recklessness, aggression and depression. In early puberty, teenagers are experiencing very rapid rises in the level of sex hormones. So mood swings at this early stage could be caused by hormones, although there is very little evidence to prove it.
Girls will continue to experience fluctuations in oestrogen and progesterone levels with their periods. Pre-Menstrual Syndrome or PMS is an acknowledged cause of irritability and mild depression in adult women. It also affects teenage girls and they might struggle to accept or control this emotional change because they are experiencing it for the first time.
Staring in the mirror
Other changes in teenagers' lives are thought to contribute to their moodiness. Their rapidly changing physical appearance can cause them to become much more self-conscious. Teenagers often start to hide themselves away, locking their bedroom doors or spending hours holed-up in the bathroom working on their appearance.
Stuck in the middle of being a child and an adult, many teenagers get frustrated. Their bodies have developed adult capabilities, but the adult world is not ready to welcome them yet.
Moodiness in the vast majority of teenagers might be difficult to live with at the time, but it passes with increasing age and confidence. However low moods persist in some teenagers and they are diagnosed with depression.
Whereas it is highly unusual for a child to become depressed, in teenage years the frequency of depression does begin to rise. The causes of teenage depression could be anything from a genetic predisposition, to stress and difficulties in family relationships.