A presentation by Robert Dan and Emily Duke

The Neuroanatomical Explanation for Schizophrenia

Ventricles are spaces in the brain filled with cerebrospinal fluid.

MRI Scans have shown differences in the size of the ventricles of schizophrenic and non-schizophrenic patients.

Ventricles

A ventricle

Its friend

Torrey found that ventricles of sufferers of schizophrenia are 15% larger than those of non-sufferers, especially in the case of Type 2 schizophrenics.

However, he suggested that the ventricles themselves were not the cause of schizophrenia but rather the decreased brain tissue due to size of the ventricles.

Torrey (2005)

Roughly 97% brain tissue, 3% ventricle.

Rougly 82% brain tissue, 18% ventricle. BIG difference.

Lambert and Kinsey put forward two possible reasons for enlarged ventricles, and thus schizophrenia.

Smaller frontal and temporal lobes: less space taken up by the lobes means more space can be taken up by the larger ventricles.

Abnormal blood flow to certain parts of the brain: More or less blood to certain parts of the brain advances/stunts growth respectively as blood carries nutrients crucial to tissue development.

Lambert & Kinsey (2005)

Frontal Lobe

Temporal Lobe

How blood comes in

Researched the relationship between size of ventricles and development of schizophrenia.

One control group: No schizophrenics, no family history of schizophrenia. A group of schizophrenics were compared to this control group.

Schizophrenics had larger ventricles and brains made more cerebrospinal fluid.

Ho et al (2004)

The study was longitudinal and followed the participants for several years. They found that the larger the ventricles became, the less easy it was for the patients to cope with their symptoms.

Ho et al (cont.)

Stop following me, already! It’s been years! Go make a dog salivate or something.

Subject is openly aware of my presence and shows signs of distress...

A problem with the neuroanatomical explanation is that it doesn’t set up a clear cause and effect system between the two events: schizophrenia development and enlarged ventricles.

Does schizophrenia cause enlarged ventricles? OR

Do enlarged ventricles cause schizophrenia?

Cause & Effect

There is no way to operationalise ventricle size from one person to the next as we all develop in different ways.

There is also no set criteria for what constitutes as “enlargement”. Ventricles naturally get bigger as we age and males tend to have larger ventricles anyway. Therefore, it is difficult to say what counts as schizophrenic-causing enlargement and what doesn’t.

Individual Differences

Researched gender differences.

Found that there are numerous different brain abnormalities in different parts of male and female brains. This questions the idea that abnormality in a specific part of the brain – such as ventricles – causes schizophrenia as we all have brain abnormalities in one way or another.

Highly et al (1999)

FIN