Schizophrenia & Depression Flashcards
Neuropsychiatric disorder
- Mental health conditions seemed to relate to atypical brain function.
- May be at neurochemical level, structural level, and/or functional level.
- Reflecting disruptions to widespread neural interactions without obvious brain lesions.
Schizophrenia: definition
Means split mind in greek (Bleuler)- but nothing to do with dissociative identity disorder.
Bleuler was referring to the split between intellectual and emotional aspects of an experience.
Schizophrenia: diagnosis
DSM-V criteria (2/5 & at least one positive):
Positive symptoms: delusions; hallucinations; disorganised speech.
Negative symptoms: disorganised/catatonic behaviour; negative symptoms (eg. blunted emotions; lack of drive).
Schiz: prevalence
Affects approx 1% of general population.
Strong genetic component- 10% in family members.
45% in identical twins- suggests environmental factors also important.
Schiz as neurodevelopmental disorder
Interaction between gene and early experiences influence development.
Causing abnormal brain development.
Typical age of onset = early adulthood.
Schiz: Biochemical abnormalities
Dopamine theory: early treatment with Chlorpromazine reduced symptoms but had Parkinsons-like side effects.
Discovered chlorpromazine might be acting on dopaminergic system which lead to dopamine theory.
Supported by effects of cocaine- cause psychotic episodes because it acts on nervous system increasing dopamine levels.
Schiz: dopamine theory (Carlsson & Lindqvist)
Chlorpromazine= dopamine antagonist- binds to dopamine receptors, blocking them.
Dopamine transmission is reduced (not levels, just activity).
The blockage of receptors sends a signal to increase the release of dopamine.
Creese et al: showed specific type of dopamine receptors that neuroleptics act on (D2).
Schiz: neuropsychological assessment
Some studies suggest only 15-30% of patients have normal neuropsychological profile.
Correlation between negative symptoms and cognitive deficits.
Particularly in: LTM, cognitive control, working memory.
Shiz: cognitive control deficits
McDowell et al, 2002: antisaccade task.
- patients with schozophrenia committed significantly more errors than controls. (40% vs 7%)
- controls showed increased BOLD levels in DLPFC (responsible for inhibition), patients did not.
Schiz summary
- Psychiatric disorder associated with genetic, biochemical and neural abnormalities.
- Biochemical level - excessive activity of the dopaminergic system may be responsible for some symptoms.
- Cognitive and neural level - patients seem to be particularly impaired on tasks involving the PFC.
- May neuroimaging studies suggest underactivity in the PFC.
Depression: diagnosis
Affective disorder.
Clinical/unipolar depression/major depressive disorder (MDD): DSMV criteria (5+ present over 2 week period- at least 1 or 2).
- depressed mood.
- reduced interest or pleasure in activities.
- weight loss/gain; increase;loss in appetite.
- sleep problems.
- psychomotor agitation or retardation.
- fatigue.
- feelings of worthlessness or guilt.
- reduced ability to think and concentrate.
- recurrent thoughts of death or suicide.
Depression: prevalence
Affects around 10% at some point.
Some evidence for genetic role.
Concordance rates of up to 60% in identical twins.
Dep: biochemical abnormalities
Reduced neurotransmitters, monoamines, found in brains of suicide victims.
Antidepressants act on monoamine transmission.
Eg. prozac is a SSRI- stops serotonin being reabsorbed, making more available at postsynaptic receptors.
Dep: neuropsychological assessment
Castenda et al, 2008: focussing on MDD in young adults.
- executive dysfunction most commonly reported cognitive deficit.
- attention deficits.
- learning and memory impairments: visual and verbal STM; working memory.
Dep: functional neural abnormalities
Depressed people show bias towards negative thinking.
This may perpetuate the condition (Teasdale)- depressed mood makes negative memories more accessible.
