schizophrenia Flashcards
evidence of genetic vulnerability
1 – 4 %
- Earlier first episode in men; men have higher and longer hospitalisation and worse prognosis than women
- Higher rate among the urban poor
- In part a genetic disorder
paranoid schizophrenia
- extensive hallucinations
- systemised delusions
- intense or formal presentation
hebephrenic schizophrenia
- hallucinations/delusions
- disorganised and body centric
- internal focus – external neglect
- voluble/ incoherent presentation
- marked lack of hygiene
catatonic schizophrenia
- hallucinations/ delusions
- excessively excited/agitated or frozen motor activity
residual schizophrenia
- isolation/withdrawal
- flat/inappropriate emotive expression
- bizzare/incomprehensible thought
- apathy/loss of motivation
type 1 schizophrenia
- sudden onset
- hallucination/delusion, thought disorder
- positive symptoms
- excess dopamine activity -> neuroleptics
type 2 schizophrenia
- flat effect
- motivation/volition loss
- impaired speech
- negative symptoms
- structural changes in the brain
- smaller frontal lobes
- enlarged ventricles
- neuronal degeneration
acute schizophrenia
rapid, sudden onset
precipitating incident/experince
neural connectivity
- Evidence of neural connectivity impairment, particularly involving hippocampus and frontal lobe areas
- Less task-related frontal lobe activation
dopmine hypothesis
- Positive symptoms of schizophrenia could be due to excess dopamine activity
- Some recent studies show larger number of dopamine receptors (type D2) in patients’ brains
- Dopamine agonists (amphetamine, L-Dopa, etc.) can generate psychosis
- Typical antipsychotics: Chlorpromazine and haloperidol block D2 type dopamine receptors
Reduce positive symptoms, but not effective against negative symptoms
minor Side effects of typical antipsychotics
• depression, disturbed bowel movements, weight deregulation, drowsiness, menstrual problems
major Side effects of typical antipsychotics
- Extrapyramidal effects (Parkinson-like tremor and rigidity)
- Tardive dyskinesia (smacking lips, sucking and sudden movements
Atypical antipsychotics
- Clozapine and Risperidone
- block fewer D2 dopamine receptors but also block some types of serotonin receptors
- more effective on positive and negative symptoms and much better with respect to major side effects
- However, clozapine can produce agranulocytosis, a white blood cell disorder
effectiveness of drugs
- 14% first time sufferers and 25% of repeat sufferers do not respond adequately to antipsychotics
- 25% to 50% of patients who benefit from drugs continue to have positive symptoms years after their first episode
- Some of this failure could be due non-compliance with drug schedule
- Drugs help moderate symptoms, even reduce relapse risk, but fall far short of ‘curing’ psychotic conditions
brain connectivity and schizophrenia
Fornito et al (2011) recently used this AX-continuous performance task to isolate differences in functional connectivity between schizophrenia sufferers and matched healthy controls. Each trial in the task involves a CUE letter and a PROBE letter. Only when the CUE is the letter A and the probe is the letter X, the response should be a button-press with the right index finger. In all other cases, the response should be a button-press with the right middle-finger. Notice that the AX pairing is most frequent, setting up a tendency towards the index finger response when the probe is X. When the combination seen is BX, however, cognitive load is high, because inhibitory mechanisms need to kick in (along with working memory, which holds the response rule and the identity of the cue letter) to suppress the index finger response and initiate the middle finger response.
