Psychiatry is a branch of medicine which studies and treats mental disorders. The word originates from the Greek words for mind or soul (psyche) and heal or medical treatment (-iatry). A practitioner of psychiatry is known as a psychiatrist and is a trained medical doctor who has chosen this field in which to specialise, requiring several years’ further training. They are not to be confused with psychologists who are not medically trained and study human behaviour, although the two professions can work closely together.

Before a psychiatric diagnosis can be made, a patient must undergo a thorough biological assessment to rule out other possibilities first, such as a brain scan for tumours and blood tests. The patient will be interviewed and information may also be gathered from other external sources such as relatives of the patient and other medical professionals. Mental illness is seen to be a disorder of the brain itself, with the circuits of the brain affected by genetic factors or by the life experiences of the patient.

There are many branches of psychiatric illness, which are grouped into four areas – cognitive, affective, perceptual and behavioural. Cognitive processes are involved in the way we gather information on the world, such as language, memory and problem solving, and can be severely affected by dementia. Affective disorders are those connected with feelings and emotion. Perception is how someone understands and is aware of the world around them and behaviour is the response a person makes to his environment, whether subconscious or conscious.

A psychiatric disorder may be treated with medicine, for instance bi-polar disorder can be made more manageable by taking lithium salts, which acts a mood-stabiliser, helping with both the depression and the mania. There are other treatments such as electroconvulsive therapy, or ECT, which has been in use since the 1930s although not without controversy as to its efficacy. It involves inducing an artificial seizure in the patient and can be useful in treating severe depression or mania, particularly where a patient has failed to respond to earlier medication.

The history of psychiatry has evolved over many centuries, from the ancient Greeks and the Middle Ages, to a much greater understanding that began in Victorian times. Over that period, the way mental disorders are viewed has changed dramatically and now it is thought that problems such as addiction which were previously seen as moral weakness are now classed as mental illnesses and therefore have to be treated as such.