Psychotic disorders Flashcards
Schizophrenia defining characteristics
Chronic psychotic disorder
Distortions of thinking and perception
Inappropriate of blunted affects - emotion, language, sense of self and behaviour
Clear consciousness and intellectual capacity maintained (cognitive deficits may evolve)
Psychopath phenomena - thought echo/insertion/withdrawal, broadcasting, delusional perception, delusions of control/influence/passivity, hallucinatory voices, thought disorder and neg Sx.
What is a hallucination
A perception in the absence of external stimulus
What is a delusion
A fixed, false unshakeable belief, despite ration argument/evidence to the contrary; cannot be explained by pts cultural, religious or education background; process by which arises in bizarre and illogical
What is schizophreniform disorder
Psychotic illness with Sx of schizophrenia present for significant portion of time for at least a month, but signs last less than 6 months
Pathophysiology/aetiology/RFs of schizophrenia
Onset 15-45 years; men affected earlier and more severely; rarely presents in childhood and is associated wit developmental delay
Genetics
- FHx biggest RF - esp 1st degree relative
- Likely multiple susceptibility genes
- Adoption studies - children with FHx, still at high risk
Obstetric complications
- Maternal prenatal malnutrition or viral infection
- Pre-eclampsia
- Low birthweight
- Emergency caesarian
Substance misuse
- Cannabis, amphetamines, cocaine, LSD - can produce psychotic Sx
- Cannabis does not cause SCZ; increases risk even more in susceptible
Social disadvantage
- Low socio-economic status
- Not from birth; downward drift due to illness/social isolation/unemployment
Urban life and birth
- Higher prevalence in urban areas
Migration and ethnicity
- 1st+2nd generation immigrant have 3x increased risk
Expressed emotion
- Close contract with highly critical/over-involved relatiuves doubles the risk of relapse in period following discharge
Premorbid personality
- Premorbid schizoid personality predates SCZ in 25% cases
- Schizotypal disorder is associated with schizophrenia
Adverse life experience
- Sexual or physical abuse in childhood or adulthood
COMT in SCZ
COMT enzyme located on chr 22q11 - encodes catechol-O-methyl-transferase involved in dopamine metabolism
Two alleles of COMT - Val and Met- Valine to methionine substitution = less enzyme activity
In SCZ relationship between first age cannabis use and disorder onset is mediated b COMT genotype; Cannabis increases the risk of developing SCZ younger if you have the ValVal genotype. Onset in Met-Met genotype is not really influenced by cannabis.
Schizophrenia theories
Neurodevelopment - Initial brain abnormalities (genetic or early brain damage) + maturation of the brain along with other RFs -> functional and connectivity abnormalities
Neurotransmitter - Dopamine hypothesis - SCZ as a result of dopamine overactivity in certain areas; pos Sx: excess DA in mesolimbic tracts; neg Sx: deficient DA in mesocortical tracts. Evidence: antipsychotics are dopamine antagonists; work better for pos Sx; dopaminergic agents (amphetamine, cocaine, L-dopa) induce psychosis
Psychological - Cognitive models: subtle thinking defects predispose to delusions
Key dopaminergic pathways of the brain
Mesolimbic
- Projections from ventral tegmental area (VTA) in midbrain to ventral striatum (includes nucleus accumbens and olfactory tubercle)
- Involved in feelings of pleasure and reward
- Thought to play a role in pos Sx of SCZ
Mesocortical
- Projections from VTA to prefrontal cortex
- Involved in cognition and executive function (dorsolateral prefrontal cortex), and emotions and affect (ventromedial prefrontal cortex)
- Though that hypofunction of this pathway leads of cognitive and negative Sx of of SCZ
Nigrostriatal
- Projections from substantia nigra pars compacta (SNc) to caudate nucleus and putmen (both in dorsal striatum)
- Contains ~80% of DA in the brain
- Involved in motor planing and stimulating purposeful movement
- D2 anatagonists i.e. typical antipsychotics, can interfere with this pathway to cause extrapyramidal Sx.
Tuberinfundibular
- Projections from arcuate and periventricular nucleus of hypothalamus to the infundibular region of hypothalamus, specifically the median eminence
- DA released into portal circulation which connects to the pituitary; DA acts to inhibit prolactin release
- D2 antagonists can prevent this function causing hyperprolactinaemia -> can affect menstrual cycle, libido, fertility, bone health or cause galactorrhoea
Clinical stages of SCZ: Prodrome
At-risk mental state (ARM) before SCZ
Low grade Sx: social withdrawal, loss of interest in work, study, relationships
No frank psychotic Sx
Pts usually in late teens/early 20s
May have dropped out of college or work after a period of increasing absences
My seem distant with no reason for isolating themselves
Stages of SCZ: Acute phase
Mainly positive Sx (neg Sx may also be present)
Auditory hallucinations
Delusions
Overvalued idea - firmly held belief which itself is acceptable/comprehensible, but dominates thinking/behaviour
Thought interference - withdrawal/insertion/broadcast
Formal though disorder - may be disjointed, hard to follow; poverty of thought and though blocking may occur
Depersonalisation - feels unreal, detached, numb, emotionally distant
Derealisation - world feels unreal
Types/examples of auditory hallucinations in SCZ
Voices discussing or arguing about the patient ‘no one likes her’ ‘yea its because shes ugly’ ‘
Voices giving a running commentary ‘now hes falling asleep’ ‘now hes calling a cab’
Thought echo ‘the voices day the patients own thoughts out loud
Types of delusions in SCZ
Primary delusion: appear suddenly, no explanation for them
Secondary delusion: manifests as an attempt to explain strange experiences
Persecutory: belief someone wants to harm them (common)
Erotomanic: belief someone is in love with them
Grandiose: belief they have superior abilities/qualities
Somatic
Nihilistic: belief pt is dying, homeless or they are rotting (absence of something important)
Delusions of reference: beliefs that ordinary objects/events/actions have a significant meaning
Delusions of jealousy
Delusions of guilt
Hypochondriacal delusions: belief they have an illness
Idea of reference: belief that events relate to them personally
Delusional perception: real perception interpreted in delusional way
Passivity: belief that movement/sensation/emotion/impulse are controlled by an outside form
Thought disorders in SCZ
Circumstantiality: gives excessive unnecessary detail, but eventually returns to the original point
Tangentiality: wandering from a topic without returning to it
Neologisms: new word formations, might include combining two words
Clang associations: ideas are related only by the fact they sound similar or rhyme
Word salad: completely incoherent speech where real works are strung together into nonsense sentences
Loosening of associations/derailment: going from one idea to the other, without link
Knights move thinking: severe type of loosening of associations, where there are unexpected and illogical leads from one idea to another
Flight of ideas: leaps from one topic to another but with discernible links between them
Perseveration: repetition of ideas or words, despite attempt to change the topic
Echolalia: repetition of someones speech, including the question that was asked
Stages of SCZ: Chronic phase
Negative Sx reflecting things that are lost in SCZ
Apathy - loss of motivation
Blunted/flat affect - decreased reactivity to mood
Anhedonia - inability to enjoy interests/activities
Social withdrawal
Poverty of thought and speech
May manifest as a lack of attention to personal hygiene/care, reduced repertoire of activities and social isolation
Schneider’s first rank Sx
Delusional perception
Passivity
Delusions of thought interference
Auditory hallucinations: echo, third person, running commentary
