Psychotic disorders Flashcards
Define psychosis
- A set of symptoms, not a diagnosis itself
- The presence of hallucinations or delusions
What is a hallucination?
- A perception without an accompanying stimulus
- In any sensory modality
- Visual hallucinations are frequently caused by organic pathologies (e.g. tumour, eye disease)
Give some examples of hallucinations that are not pathological
- Hypnogogic - experienced when going to sleep
- Hypnopompic - experienced upon waking
What is a delusion?
- A fixed, false belief which is unshakeable
- Outside of cultural norms
What are some misconceptions about schizophrenia?
- Not ‘split mind’
- Patients are no more dangerous than any other patient
- Only 5% of violent crimes are committed by those with severe mental illness
What are the clinical features of schizophrenia?
- Auditory hallucinations
- Passivity experiences
- Thought withdrawal, broadcast or insertion
- Delusional perceptions
- Somatic hallucinations
How can auditory hallucinations appear?
- Thought echo - hearing thoughts out loud
- Running commentary
- Third person - multiple voices talking about the patient
What are passivity experiences?
- Belief that an action or feeling is caused by an external force
What is thought withdrawal?
- Belief thoughts are being taken out of the mind
What is thought broadcast?
- Belief that everyone knows what patient is thinking
What is thought insertion?
- Belief that thoughts are being implanted by others
What are delusional perceptions?
- Attribution of a new meaning to a normally perceived object
What are somatic hallucinations?
- E.g. the sense of being touched when no one is there
What are the positive symptoms of schizophrenia?
- Something added
- Delusions
- Hallucinations
- Thought disorder (problem with organisation of thoughts)
- Lack of insight
What are the negative symptoms of schizophrenia?
- Something taken away
- Underactivity
- Low motivation
- Social withdrawal
- Emotional flattening
- Self neglect
What is the dopamine theory describing the pathophysiology of schizophrenia?
- Drugs that increase dopamine levels (e.g. amphetamines) induce psychosis
- Drugs that antagonise dopamine treat psychosis (especially those that act at D2 receptors)
What structural changes could lead to schizophrenia?
- Enlarged ventricles
- Decreased grey matter
- Decreased temporal lobe volume
- Reduced size of limbic structures and prefrontal cortex
- Changes at synapses
- Fewer oligodendrocytes
- Fewer thalamic neurones
What is the possible role of the basal ganglia in schizophrenia?
- Some schizophrenics show movement disorder features
How is schizophrenia treated?
- Typical antipsychotics
- Atypical antipsychotics
What is the action of the typical antipsychotics used to treat schizophrenia?
- Block D2 receptors throughout the CNS
- Antipsychotic action from inhibition of mesolimbic and mesocortical pathways
- Side effects come from blocking other pathways
What is the mechanism of action of the atypical antipsychotics?
- Lower affinity for D2 receptors than typicals so milder side effects
- Also block 5HT2 receptors (so some action on serotonin systems)
What are the side effects of the atypical anipsychotics?
- Can affect movement due to involvement of nigrostriatal pathways (similar to Parkinson’s disease)
- However, untreated patients can also develop hypokinetic movement disorders (catatonia)
- Endocrine side effects
What can cause hypokinetic movement disorders in schizophrenic patients?
- Might be caused by involvement of GABA
What are the endocrine side effects of antipsychotics?
- Dopamine normally inhibits prolactin release
- Antipsychotics lead to increased prolactin levels
- Amenorrhoea
- Galactorrhoea
- Decreased fertility
- Decreased libido
- Osteoporosis
What are the challenges in treating schizophrenia?
- Patients tend to lack insight, which can affect compliance with treatment
- To get around this, medication can be given in different ways such as a depot injection
What is the prognosis of schizophrenia?
- If treatment is started early then good outlook
- About 50% will do well long term
What are the factors associated with a good prognosis for schizophrenia?
- No family history
- Good premorbid function
- Acute onset
- Mood disturbance
- Prompt treatment
- Maintenance of motivation
What are the long term complications of schizophrenia?
- All cause mortality twice as high as general population
- Shorter life expectancy
- Higher incidence of cardiovascular, respiratory disease and cancer
- 9x greater suicide risk than general population
- 2x greater risk of violent death than general population
- Substance misuse is common
- Many patients smoke
