12- psychosis Flashcards
Definition of psychosis
The presence of hallucinations or delusions. Describes symptoms not a diagnosis
Definition hallucinations
Perception without a stimulus. Can be in any sensory modality.
Definition delusions
A fixed false belief which is unshakeable. Outside of cultural norms
When are hallucinations normal
Hypnogogic- as you fall asleep. Or hypnopomic- as you wake up.
First rank symptoms of schizophrenia
Auditory hallucinations, passivity experiences, thought withdrawal, broadcast or insertion, delusional perceptions, somatic hallucinations
Auditory hallucinations
- Thought echo- hearing thoughts aloud
- running commentary
- third person voices having a conversation
What is a passivity experience
Patient believes an action or feeling is caused by an external force
Thought withdrawal
Thoughts are being taken out of the mind
Thought broadcast
Everyone knows what the person is thinking
Thought insertion
Thoughts implanted by others
Delusional perception
“Attribution of new meaning, usually in sense of self reference to a normally perceived object”
Eg. The traffic lights went read and in knew that aliens were going to land soon
Somatic hallucinations
Mimics feelings from inside the body
Positive vs negative symptoms
+ve- delusions, hallucinations, thought disorder, lack of insight
-ve- under activity, low motivation, social withdrawal, emotional flattening, self neglect
3 things thought to be involved in pathophysiology of schizophrenia
Dopamine pathways, brain changes, limbic system
Describe the dopamine (DA) theory of schizophrenia
Drugs eg. Amphetamines cause relapse of DA induce psychotic symptoms. Allmedications t that antagonise DA receptors can be used to treat psychosis
What are the 4 DA pathways
Mesocortical, Mesolimbic, nigrostriatal, tuberoinfundibular pathway
Describe the mesolimbic pathway
From ventral tegmantal area to limb in structures and nucleus accumbens.
Describe the mesocortical pathway
From ventral tegmental area to frontal and cingulate cortex.
Which pathways are under/overactive in schizophrenia
Mesolimbic- overactive. Mesocortical- under active
Brain changes in schizophrenia
Enlarged ventricles, reduced grey matter, decreased temporal lobe volume, reduced hippocampal formation, amygdala, parahippocampal gurus and prefrontal cortex
Neuropathology of schizophrenia
Decreased pre-synaptic markers, decreased oligodendroglia, fewer thalamic neurones.
Theory of aberrant connectivity
Other theories of cause of schizophrenia
Involvement of limbic structures, basal ganglia involvement
Treatment of schizophrenia
Antipsychotics- D2 blockers in all CNS dopaminergic pathways, and mesolimbic/mesocortical pathways.
Atypical antipsychotics- lower affinity for D2 receptors, blocking 5HT2 receptors
Where are D2 receptors located
Striatum, substantia nigra, pituitary gland
Describe nigrostriatal pathway
From substantia nigra pars compacta to striatum
How does dopamine affect activity of cortex
Less dopamine, less excitation
Difficulties of atypicals
Weight gain, loss of motivation
What can happen if Parkinson’s patients are prescribed with Levadopa
They can become psychotic.
What is catatonia
Catatonia is a type of schizophrenia that usually involve a lack of movement and communication, and also can include agitation, confusion, and restlessness. Cannot move for a period of time
Symptoms catatonia
Stupor, excitement, posturing, negativism, rigidity,waxy flexibility
What causes catatonia
Less gaba binding so loss of inhibitory effect
Describe tuberoinfundibular pathway
From accurate and periventricular nuclei of hypothalamus to infundibular region of hypothalamus
How do antipsychotics cause their side effects and what are they
- amenorrhoea, galactorrhoea, decreased fertility, reduced libido, osteopenia/osteoporosis
- dopamine normally inhibits prolactin release from pituitary. DA antagonists lead to loss of DA inhibitor, increasing prolactin release.
Difficulties treating schizophrenia
Lack insight so don’t always take medication.
Prognosis schizophrenia
- the earlier treatment the better
- good prognosis associated with absence of family history, acute onset, mood disuurbance, prompt treatment, maintenance of initiative and motivation
Why is prognosis poorer for other conditions with schizophrenia
-shorter life expectancy, morre CVS and resp disease, higher suicide risk, higher risk of violent death, substance misuse, cigarette smoking.
