Chapter 19, Antipsychotics Flashcards
Schizophrenia DSM-5 definition
- Delusions of persecution and auditory
hallucinations are common - Grossly disorganized or abnormal motor
behaviour - Language, particularly speech, often
disorganized or incoherent - Negative symptoms: reduced emotional
expression, lack of volition, social
withdrawal, apathy, - Cognitive defects
Schizophrenia diagnosis requires
- Two or more of the following for at least 1 month
- Delusions*
- Hallucinations*
- Disorganized speech*
- Grossly disorganized or catatonic behaviour
- Negative symptoms, such as diminished emotional expression
Positive symptoms of Schizophrenia
- hallucinations
- delusions (e.g., paranoia)
- thought disorders
- movement disorders
- depersonalization
Negative symptoms of Schizophrenia
- flat affect
- lack of pleasure
- social withdrawal
- alogia (poverty of speech)
- loss of interest and motivation
if positive symptoms are dominant - tend to be older at onset
- respond well to antipsychotic medication
Cognitive symptoms of schizophrenia
- disorganized thinking
- poor concentration
- poor memory
- difficulty expressing ideas
- difficulty integrating thoughts and feelings
if negative symptoms are dominant - sometimes mistaken for other disorders (e.g., depression)
- symptoms are resistant to current treatments
Abnormalities of brain structure and function in schizophrenia
- cerebral atrophy and ventricle enlargement
- disorganized hippocampal cells
- abnormal myelination and organization of white matter tracts
- reduced function of PFC (hypofrontality) ( PET scans show less blood flow to the frontal cortex when performing cognitive tasks
Inflammation and Schizophrenia
- blood levels of pro-inflammatory cytokines are elevated and anti-inflammatory cytokines are reduced; levels return to normal after successful antipsychotic drug treatment.
- prenatal inflammation may cause abnormal neurodevelopment that increases the risk for schizophrenia.
The neurodevelopmental model of schizophrenia
Genetic vulnerability in combination with environmental
stressors alter the trajectory of brain development, ultimately
resulting in the symptoms observed in schizophrenia
* Negative and cognitive symptoms caused by reduced frontal lobe function
* Positive symptoms caused by excessive mesolimbic DA activity following
early mesocortical cell loss (which could be due to genetics or
environmental events)
Dopamine hypothesis of schizophrenia
excess DA function results in the positive symptoms of schizophrenia
* There is overlap in symptoms between stimulant-induced psychosis
* Amphetamine-induced Psychosis can be treated with psychosis
* Amphetamines make symptoms worse in patients with schizophrenia
DA imbalance hypothesis of schizophrenia
symptoms are due to reduced DA function in mesocortical neurons along with excess DA function in mesolimbic neurons