Psychosis & Schizophrenia Flashcards
Explain the factors in the formulatgion of psychosis
Genetic vulnerability to expression of the illness or disorder
Environmental influences - macro enviornment such as life events, exposures, and micro environment such as cellular biochemistry, hormones, neurotransmitters
If you don’t have the gene, but have psychosis/schizophrenia, a gene is not altered and cannot be passed genetically. Macro-adaption may occur if macro-environmental influences happen throughout generations, can cause genetic mutation of a gene
Explain psychosis
Psychosis is a thought disorder characterized by disturbances of reality and perception.
Perceptual distortions - cognitive disorders characterized by an impaired ability to percieve the nature of objects or concepts through the sense organs. These include spatial neglect syndromes, where an individual does not attend to visual, auditory or sensory stimuli presented from one side of the body.
Involves impairment of cognitive functioning
Inappropriate or diminished affect (mood)
Delusions - are defined are fixed, false beliefs that conflict with reality
Explain schizophrenia
A serious mental disorder in which people interpret reality abnormally. Schizophrenia may result in some combination of hallucinations, delusions, and extremely disordered thinking and behavior that impairs daily functioning, and can be disabling.
Separated into positive and negative symptoms
Positive: hallucinations, delusions, paranoia, ideas of reference, catatonic behaviour, agitation, disorganised speech
Negative: apathy, social withdrawal, anhendonia, emotional blunting, cognitive defects, extreme inattentiveness or lack of motivation to interact with the enviornment
Explain the different subtypes of schizophrenia
Paranoid: characterized by predominantly positive symptoms of schizophrenia, including delusions and hallucinations.
Disorganized: disorganized behaviour and speech and includes disturbance in emotional expression. Hallucinations and delusions are less pronounced with disorganized schizophrenia, though there is evidence of these symptoms occurring.
Catatonic: rare severe mental disorder characterized by striking motor behaviour, typically involving either significant reductions in voluntary movement or hyperactivity and agitation
Undeferential: an outdated term describing a subtype of schizophrenia that the medical community no longer recognized
Schizoaffective: abnormal thought processes and an unstable mood
Simple: onset of prominent negative symptoms and the lack of delusions, hallucinations, and thought disorder are the essential clinical features of simple schizophrenia
Residual: subtype of schizophrenia in which the individual has suffered an episode of schizophrenia but there are no longer any delusions, hallucinations, disorganized speech or behaviour
Explain the dopamine hypothesis
The dopamine hypothesis explains that hyperactivity of dopamine D2 receptor neurotransmission in subcortial and limbic brain regions contributes to positive symptoms of schizophrenia.
High levels of production of doapmine can cause psychosis.
Explain the dopamine pathway
The mesolimbic pathway is a dopaminergic pathway in the brain. This is where the anti-psychotic medication is intended to go. Anti-psychotics work by blocking the post synaptic receptor D2.
However, if it doesn’t go to the intended D2 receptor, it can block other dopamine receptors which means the service user can experience apathy, depression etc. This is known as the mesocortial pathway.
Explain the nigrostriatal pathway
The nigrostriatal pathway is a dopaminergic pathway that is helps with co-ordination and movement.
Side effects can include trembling, shakiness, poor co-ordination etc (similar to Parkinson’s). Parkinson’s disease is a result of not enough dopamine within this pathway.
Explain the tuberoinfundibular pathway
The tuberoinfundibular pathway is one of the major dopamine pathways. Dopamine released at this site regulates the secretion of prolactin from the anterior pituitary gland. Some anti-psychotic drugs block dopamine in the tuberoinfundibular pathway, which can cause an increase in blood prolactin levels (hyperprolactinemia). This can cause abnormal laction (even in men), disruptions to menstrual cycle in women, visual problems, headaches, sexual dysfunction and oestoprosis in women.
Explain the glutamate theory
Glutamate is an agonist neurotransmitter.
Evidence suggests psychosis can be caused by glutamate. The glutamate hypothesis of schizophrenia is cantered on a deficiency in activity of glutamate at the glutamate synapse, especially in the prefrontal cortex. In many brain areas, dopamine inhibits glutamate release, or glutamate excites neurons that dopamine inhibits.
GAD67 can help in the reduction of glutamate by an intermediary. Uses GABA to reduce glutamate. GAD67 then produces GABA which reduces glutamate.
There is not yet an anti-psychotic based on the glutamate theory, only dopamine theory. However, are physical health medications that used the glutamate. New evidence may be moving towards using these physical health medications for schizophrenia.
Explain the use of conventional/typical anti-psychotics
First generation anti-psychotics were the first medications produced to reduce psychotic symptoms - mesolimbic pathway was unknown at this time. Therefore, it only blocks D2 receptors. However, they found some of these medications were causing low blood pressure and blocking the alpha 1 receptor for the heart.
• Strong dopamine D2 receptor antagonists
• Alpha adrenergic receptor - cardiovascular
• Histamine receptors – weight gain, sedation
• Muscarinic cholinergic receptors – dry mouth, constipation, urinary retention, blurred vision
Different medications have different ability to cause those side effects
Explain the use of atypical anti-psychotic’s
Atypical anti-psychotics are second generation anti-psychotics. They are classified as serotonin (dopamine antagonist). The serotonin inhibits the release of dopamine in various dopamine pathways but the degree of control differs from one pathway to another. They have fewer EPS modulated by the 5HT2A component, and can improve positive and negative symptoms. However, they can cause metabolic disorders.
