Schizophrenia Flashcards
What is schizophrenia?
Separation between perception, memory, personality and cognition
What is the impact of schizophrenia?
- Typically occurs between 15-45 years of age
- High suicide rate
- Many having to live in assisted care/with families
- Only 25% recover
What are the positive symptoms of schizophrenia?
Acute -> respond to treatment
- Hallucinations (auditory, visual, olfactory)
- Delusions (grandeur, paranoia)
- Thought disorder
What are the negative symptoms of schizophrenia?
- Affective flattening
- Apathy and social withdrawal
- Alogia (lack of speech)
- Anhedonia (inability to experience pleasure)
What are the different subtypes of schizophrenia?
Paranoid - Delusions of persecution
Disorganised - Early onset with personality deterioration
Catatonic - Mutism and abnormal postures (rare)
What are the causes of schizophrenia?
Genetic - however not full story as only co-occurance of 50% of monozygotic twins
Environmental factors - such as drug use in developmental years and prenatal stressors
What is the pathology of schizophrenia?
Evidence of neurodeveopmental disorder with defects in cortex (atrophy) and enlarged cortices
HOWEVER NO CLEAR PATHOLOGY
What is the dopamine hypothesis of schizophrenia?
- Over activity of the dopaminergic neurons innervating the mesolimbic and mesocortical pathways
- Mesolimbic cortex associated with emotions and memory (positive symptoms?)
- Prefrontal cortex involved in organisation of behaviour, motivation, planning, attention, and social behaviour (negative symptoms?)
What is the evidence supporting the dopamine hypothesis?
- Drugs acting as dopamine agonists induce psychosis (e.g cocaine)
- Antipsychotic drugs tend to block dopamine receptors
What were the first drugs used to treat scizophrenia?
Antipsychotics e.g chloropromazine which had sedative effect
- Later found to be dopamine antagonist
- However 15-30% of patients ‘drug resistant’
What are the ‘atypical’ second generation drugs to treat schizophrenia?
e. g Clozapine
- Less side effects
- Better treatment of negative symptoms
Which receptors do the typical schizophrenia drugs act on?
- High affinity for D2 present in limbic system but also nigrostriatal pathway (cause parkinsons-like symptoms)
- Occupancy of histamine receptors associated with sedative effect
What receptors do the atypical schizophrenia drugs act on?
- Bind to many receptors
- Affect D3 and D4 receptors in the cortex creating less Parkinsons-like effect
- Possible increased 5-HT activation may be decreasign negative symptoms
What are etrapyramidal motor disturbances?
- Associated with block of D2
- Involuntary movements, rigidity (Parkinson’s-like) typically disapear after first weeks of treatment
- Tarditive dyskinesia (involuntary movements in face/body trunk) can occur in 20-40% of patients for months or years of treatment relating to adaptive hypersensitivity of nigrostriatal pathways that can be irreversible
What are the endocrine side effects of schizophrenic treatment?
D2 usually inhibits prolactin, inhibition can therefore lead to breast swelling and lactation in men and women
