Disorders of the CNS Flashcards
What are some examples of CNS disorders?
Schizophrenia - 1:100
Bipolar disorder - 1:100
Depression - 1:10
Anxiety disorders - 1:20
What are some positive symptoms of schizophrenia?
Hallucinations - sensory perception with no external stimulus, all senses and often voices
Delusions - often paranoid, primary delusions spontaneous, sudden secondary delusions reflect situation
Thought disorder - conscious thought, loosening of associations and speech and language
All together this is called psychosis
What are some negative symptoms of schizophrenia?
Social withdrawal
Flattening of emotional responses
Anhedonia
Disinterest in everyday tasks
Cognitive deficits e.g. Attention, memory
Overall: Guilt, depression, anxiety and self harm
What is the relationship with age and type of schizophrenic symptoms?
This can lead to suicide attempts (50%) with 10% successful
Younger patients - more positive symptoms, relapsing/remitting
Older patients - more negative symptoms, chronic/progressive
What are the genetic causes of schizophrenia?
As first degree relatives - there is a strong correlation with cases, compared with second/third degree relatives
This was mainly shown by identical twins as if one develops this, there is a 60% chance the other one will
However, due to 40% that will not develop this, there must be some environmental factors
What are some environmental factors of schizophrenia?
Maternal viral infection Maternal famine Maternal stress Cannabis consumption Winter/spring birth Urbanisation
What is the pathology of schizophrenia?
The dopamine turnover hypothesis:
Increased dopaminergic activity leads to psychosis
Dopaminergic antagonists or partial agonists antipsychotic
Mesolimbic pathway ↑ – positive symptoms
Mesocortical pathway ↓ – negative symptoms
More recently – NMDA receptors also involved and therefore the NMDA hypofunction hypothesis
There are changes in the grey matter in schizophrenic’s
The loss of neurones is great
What is bipolar affective disorder?
Characterised by mood swings
The two ends are mania and depression
Mania - excited, euphoric, irritable, lack concentration, talk fast, poor judgement, insomnia, high sex drive, denial that anything is wrong etc…
Depression - sad, anxious, pessimism, worthlessness, feeling ‘slow’, over sleeping, change in appetite, thoughts of death/suicide etc…
What are the causes of bipolar affective disorder?
Some evidence for genetics, e.g. Twin studies (not strong evidence)
Probably polygenic with environmental factors
5-HT, Dopamine and Glutamate transmitter systems affected
Changes in Cell growth and/or maintenance pathways affected in the brain e.g. Reduced BDNF
What is the pathology of bipolar affective disorder?
There are changes in volume of the insular grey matter
White matter in frontal areas are affected
What are the symptoms of depression?
Emotional symptoms Low mood, negative thoughts, misery, pessimism, apathy Low self esteem Indecisiveness Anhedonia
Biological symptoms
Retardation of thought, action
Loss of libido
Sleep, appetite disturbance
What is the cause of depression?
Monoamine theory
Caused by decreased function of 5-HT and NA systems
What is the patholgy of depression - neuroendocrine mechanisms?
There is a decrease in the release of 5-HT and NA, which affects the hypothalamus - this can affect the kidney, anterior pituitary gland
This leads to increased cortisol
Plasma cortisol high in depressed patients
Cortisol doesn’t fall/respond in depressed patients following dexamethasone
CRH high in depressed
CRH injection into brain causes depression symptoms
○ corticotrophin-releasing hormone (CRH)
○ This is done in animals
What is the patholgy of depression - trophic effects?
Neurone loss in hippocampus, prefrontal cortex Shown by: Ventricular enlargement Hippocampal shrinkage Prefrontal atrophy Reduced neuronal activity in same
What is the treatment of depression?
Monoamine uptake inhibition
Monoamine receptor antagonists
Monoamine oxidase inhibitors
Monoamines - Dopamine, 5-HT and Noradrenaline
