WE ARE OUR BRAINS - CHAPTER 10
SCHIZOPHRENIA AND OTHER REASONS FOR HALLUCINATIONS
Schizophrenia affects only 1% of the population, but because suffered have it for such a long time, half of the beds in psychiatric hospitals are filled with schizophrenic patients.
They are often depressed and 10% of them try to kill themselves.
"Positive" symptoms: delusions and hallucinations. Areas of the brain that process auditory and visual input are extremely active. They cannot be distinguished from real experiences because they are processed in the same brain regions as them. Delusions are the belief that they are being watched or controlled by mysterious powers.
Negative symptoms: loss of normal abilities: taking initiative, organising one's life, tidying up one's room, looking after oneself, muted emotions, cognitive deterioration. Many take drugs or addictive substances to try to combat the negative symptoms, but they exacerbate the positive symptoms. The negative symptoms are caused by reduced activity in the prefrontal cortex.
Schizophrenia is more common in men. Psychosis starts around the age of twenty. It is largely due to genetic factors. In women there is a second peak of symptoms around menopause.
Female hormones reduce the negative symptoms if taken alongside standard medication.
With its progression, the brain shrinks and its ventricles become larger. The same is seen in ageing and dementia. There are no brain changes specific to schizophrenia, so diagnosis depends on psychotic investigation.
There is an 80% genetic component to the disease. Tiny variations in genes for brain development and/or production and breakdown of chemical messengers in the brain.
Maternal malnourishment in the first three months of pregnancy doubles the risk for schizophrenia.
There is also higher risk if the child is born in winter or if the mother had the flu during her sixth month of pregnancy.
Toxoplasmosis and Borna disease virus also increase the risk.
Life events: the death of a relative or stress during pregnancy.
Problems during birth: forceps delivery, low birth weight, need for an incubator period, premature birth.
Many cells of the hippocampus are in disarray, there are also groups of cells that have failed to migrate to the right place in the cerebral cortex: early development problems even though the symptoms start later in life.
If the brain stop receiving information the normal way, it starts making up information. A deaf patient hearing non-stop songs in his head until magnetic stimulation of the auditory cortex can stop it temporarily and hearing glasses can stop it permanently.
Charles Bonnet Syndrome: visual hallucinations in individuals with impaired eyesight.
Korsakoff's Syndrome: demential that causes fake memory confabulations.
The same principle applies to schizophrenic hallucinations, which is why magnetic stimulation of those areas reduces them. Conversely, isolation cells which they are usually put in in institutions, diminish brain input even further, making the symptoms worse.
Mountaineers, especially when alone, may have very vivid hallucinations, out of body experiences or be overcome by fear.
Delirium: confusion, restlessness, memory problems, aggression, noisy, hyperactive. The people do not know where they are, can't think or concentrate, often hallucinate, see creepy crawlies everywhere, refuse food because it is filled with bugs, believe their bed is a grave etc. It is cause by a dopamine overdose, so your susceptibility to it depends on your polymorphisms in the DNA of the gene that produces the protein that receives the dopamine message in brain cells. Delirium causes brain damage and increases dementia risk. it can cause long-term effects: problems walking, reading, writing, memory never fully recovers. A third of people who suffer a delirium episode over the age of 65 die within a few months.
Delirium is mostly seen in older patens who have been under anaesthesia. Up to 80% of patients in intensive care develop it. Pneumonia, dehydration, medication, drugs, malnourishment, low oxygen levels, blood sugar, infarcts, alcohol poisoning are risk factors.
Hearing voices: between 7-15% of the population hear voices, yet only a fraction have mental health problems. In healthy people it starts at a young age and runs in families. When a symptom of a mental health problem, usually the voices are with threatening, negative messages. Healthy people alone can control them, tell them to leave or call them up.