Facts about Schizophrenia
Some Quick Facts about Schizophrenia
- Approximately one percent of the population suffer from schizophrenia.
- 10 to 15 percent of those affected by the illness take their own lives, usually within the first ten years of developing the disorder.
- Typically strikes young people when they are maturing into adulthood.
- The true cause of schizophrenia is widely debated but the leading multiple convergent factors include: DNA, Gene Expression, Viruses, Toxins, Nutrition, Birth Injury, and Psychological Experiences.
- Most schizophrenics are unemployed; the governmental and family costs each year are enormous.
The Etiology of Schizophrenia
- “Schizophrenia is a disease of the brain that is expressed clinically as a disease of the mind. It is a disease of neural connectivity caused by multiple factors that affect brain development.
- Despite a hundred years of research, the neuropathology of schizophrenia remains obscure. In general, the relationship between neurochemical findings (which focus on dopamine, 5-HT, glutamate and GABA systems) and the neuropathology of schizophrenia is unclear.
- A final common pathway defines the illness: schizophrenia is a misregulation of information processing in the brain.
- Delusions
- Hallucinations
- Bizarre Behaviors
- Dissociated or fragmented thoughts
- Incoherence and Illogicallity
Negative Symptoms
- Blunted Affect
- Impaired emotional responsiveness
- Apathy
- Loss of motivation and interest
- Social Withdrawal
The differentiation of symptoms is important in the psychopharmacology of antipsychotic drugs because the classic agents affect primarily the positive symptoms, while the atypical antipsychotic drugs relieve both the positive and negative symptoms.
Dopaminergic Involvement
- In the 1970’s, scientific evidence favored a dopamine theory of schizophrenia.
- Dopamine Theory: the disorder arises from the dysregulation in certain brain regions of the dopamine system, and antipsychotic drugs work by being pharmacological antagonists of the neurotransmitter dopamine.
- The traditional view of antipsychotic drug activity involves antagonism of D2 receptors, some drugs blocking D2 receptors and some blocking D4.
- Traditional antipsychotics which block D2 receptors have been found to cause acute drug-induced Parkinson symptoms, persistent and sometimes permanent residual motor dysfunction, and may even worsen negative symptoms.
- Atypical antipsychotics are also D2 antagonists but usually have a second action; perhaps D1, 5-HT, or adrenergic blockade.
- D2 receptor blockade is thought to be associated with the abovementioned side effects but there is still a strong correlation between D2 blockade and clinical efficacy and potency.
- The exact serotonin mechanisms involved have been very elusive.
- The serotonin psychedelic drugs psilocybin and LSD produce a state similar to schizophrenia and these drugs are thought to be agonists of 5-HT receptors. 5-HT antagonism may be beneficial in antipsychotic efficacy.
- Serotoninergic activity may be a complementary action to dopaminergic blockade, reducing negative symptoms and blocking the production of abnormal drug-induced motor problems. This has been found to be true of many atypical antipsychotics that are capable of blocking 5-HT2 receptors.
Glutamate Involvement
- Olney and Farber found NMDA receptor hypofunction can cause psychosis in humans and corticolimbic neurodegenerative changes in the rat brain; changes that could in fact be prevented by certain atypical neuroleptic agents like clozapine and olanzipine.
- Therefore there is a glutamate-NMDA receptor hypofunction hypothesis of schizophrenia that is proposed to result in excessive release of excitatory neurotransmitters (glutamate and acetylcholine) in the frontal cortex, damaging cortical neurons and triggering the deterioration seen in patients with schizophrenia.
- Mohn and colleagues developed genetically engineered mice in which NMDA receptors were reduced by 95 percent. The mice exhibited behaviors remarkably similar to schizophrenia, unrelated to dopaminergic dysfunction and sensitive to antipsychotic drugs.
Source: http://wings.buffalo.edu/aru/P402chpt17.doc
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Tags: 5-HT, 5-HT2 receptors, antipsychotic drugs, apathy, Atypical antipsychotics, atypical neuroleptic agents, Birth Injury, Bizarre Behaviors, Blunted Affect, brain development, Clozapine, corticolimbic neurodegenerative changes, delusions, Dissociated or fragmented thoughts, DNA, dopamine, dopamine theory of schizophrenia, Dopaminergic Involvement, GABA, Gene Expression, glutamate, Glutamate Involvement, glutamate-NMDA receptor, hallucinations, hypofunction, Impaired emotional responsiveness, Incoherence and Illogicallity, Loss of motivation and interest, LSD, negative symptoms, neuropathology of schizophrenia, NMDA receptor, Nutrition, olanzipine, positive symptoms, psilocybin, Psychological Experiences, psychopharmacology of antipsychotic drugs, schizophrenia, Serotonin Involvement, Serotoninergic activity, social withdrawal, The Etiology of Schizophrenia, Toxins, Viruses
