Why does it happen?

In the next few sections we’re going to use the term “mental illness”, because we’re talking primarily about the development of diagnosable illnesses such as mood, psychotic and anxiety disorders. We want to acknowledge, however, that it can be difficult to distinguish between these disorders and more common, and less serious mental health problems such as having the “blues”.

Sometimes problems and stresses keep building up until there is a point where something gives, often known as a "crisis". Looking back, it may become clear that things haven't been quite right for a while.

No one's quite sure of the exact cause of mental illness, but it is generally accepted that it has to do with chemistry of the brain.

There are many different -factors that have been identified as having a possible role in causing or triggering a mental illness to develop. Genetic factors, such as having a parent or close relative with a serious mental illness (like schizophrenia or bipolar disorder) will mean that a person will have a slightly greater chance of developing the condition. Stress also does seem to play a part, and although we don’t really know that it can cause mental illness, we do know that it can act as a trigger for the illness or make it worse.