Schizophrenia

INTRODUCTION

Schizophrenia is a serious mental illness. Patients experience progressive personality changes and a breakdown in their relationships with the outside world. They have disorganized and abnormal thinking, behaviour and language and become emotionally unresponsive or withdrawn.

"The first signs, usually only noticed in looking back on events, are likely to include an unexpected withdrawal of the degree or type of contact that the person used to have with family or school. The person seems less capable of of dealing with "minor" stresses in the accustomed way. This may develop to an extreme over months or years (sometimes termed negative symptoms). Alternatively, the person may develop elaborate constructions to interpret the world, as they see it, which may reflect matters that are only in their mind (sometimes termed productive or positive symptoms, that, in the extreme, can take the form of delusions or auditory hallucinations)." (Schizophrenia: A Background Sketch http://www.biopsychology.uni-essen.de/Background%20Sketch(1).htm)

People who suffer from schizophrenia may have a very broad range of symptoms which can cause great distress to themselves and their families. These symptoms can take many forms including:

* 'Positive symptoms' (abnormal experiences), such as hallucinations (seeing, hearing, feeling something that isn't actually there), delusions (false and usually strange beliefs) and paranoia (unrealistic fear)

* 'Negative symptoms' (absence of normal behaviour), such as emotional withdrawal, and lack of motivation and enjoyment

* Cognitive dysfunction (problems with concentration, learning abilities and memory)

The lifetime risk of someone suffering from schizophrenia is about 1%, and most people first experience symptoms between the ages of 15 and 35 years.

"Schizophrenia is a chronic, severe, and disabling brain disease. Approximately 1 percent of all populations develop schizophrenia during their lifetime. In the vast majority of cases, onset of the illness occurs between the ages of 15 and 25, making schizophrenia the single biggest cause of permanent disability starting in youth. Schizophrenia causes around 10 percent of patients to suicide, usually before the age of 30. This makes the illness a major cause of youth suicide, and responsible for more deaths than AIDS, SIDS and MS combined." (NISAD: A Schizophrenia Research, What Is Schizophrenia http://www.nisad.org.au/schizophrenia/default.asp )

The cause of schizophrenia is not known, but it is thought to involve many different factors:

1) It may be partly hereditary; in other words the genes that we inherit might be partly to blame

2) The other causes of the illness remain unknown, although it is thought that schizophrenia sufferers may have some parts of the brain that have not developed in exactly the normal way

3) Some believe that something that happens in the womb might cause schizophrenia many years later

4) Possibly there is an imbalance in the chemicals that the brain uses to send messages from one cell to another

5) An attack can be brought on by stress, although this is not the cause of schizophrenia

CAUSES

The causes of schizophrenia are not known but several factors may play a role in the development of the condition:

1) Hereditary or not?

Genetic Risk of Schizophrenia

Familial Relationship Risk

Identical twin affected 50%

Fraternal twin affected 15%

Sibling affected 10%

One parent affected 15%

Both parents affected 35%

Second-degree relative affected 2-3%

No affected relatives 1%

General population 1%

Source: Roberts, Leigh, & Weinberger (1993)

(NISAD: A Schizophrenia Research, http://www.nisad.org.au/schizophrenia/default.asp )

As you can see, researchers in the past did see that schizophrenia runs in families. However, that was in 1993. Today, it has been established that over 90 percent of cases arise in families with no known medical history of mental disorders.

"...but for a large number of people who fall ill in this way there are no indicators of a "familial contribution". Even in familial cases, the contribution seems likely to arise from a number of features, each of which only makes the person vulnerable, if other things go wrong. These other things could include the person's perception of intermittent and long-lasting stress. Much research is being carried out at the moment into those features that may have adversely affected the development of the brain ("neurodevelopment") in patients who later had schizophrenia." (Schizophrenia: A Background Sketch http://www.biopsychology.uni-essen.de/Background%20Sketch(1).htm )

Also, from the NISAD website, It states that, "Schizophrenia can affect any family and in most cases arises where there is no previous history of the illness."

Thus, to assume that schizophrenia is directly caused by genes in a familial relationship is too broad and general.

2) Brain Development

The darker staining of ACC tissue indicates more glutamate receptors in the schizophrenia sample on the right compared to the control. Image courtesy of Dr Katerina Zavitsanou, NISAD Neurobiology Research Panel.

Composite brain images from normal and schizophrenia affected brains display differences. Image courtesy of Paul Rasser, NISAD Cognitive Neuroscience Research Panel.

Here, it shows how the brain develops differently for people with Schizophrenia. Despite the differences seen, "[Such as]abnormalities in brain structure (for example, enlargement of the fluid-filled cavities called the ventricles in the interior of the brain, and decreased size of certain brain regions) or function (for example, decreased metabolic activity in certain brain