Psychosis - schizophrenia

ICD-10 definition of psychosis

Characterised by a fundamental and characteristic distortion of thinking and perception.

And by inappropriate or blunted affect

• BUT maintained intellectual capacity and clear consciousness

ICD-10 diagnostic qualifiers for schizophenia

1 syndrome or 2 symptoms for most of the time or at least a month

• not a manic depressive episode

• Not attributable to organic brain disease

• not attributable to alcohol/drug related intoxication

How does the ICD-11 differ from the ICD-10 for schizophenia

• there are no more schizophrenia subtypes

• improved diagnostic utility

• pathogenomic relevance to first rank symptoms has been removed

Thought based syndromes of schizophrenia

• thought echo

• thought insertion

• thought withdrawal

• thought broadcasting

Delusion syndromes of schizophrenia

• Delusions of control/influence

• passivity of thought or action or sensation

• delusional perception

• persistent delusions with cultural or religious context

Delusion

Fixed firm belief that is not based on religious background/culture

• persists despite evidence to the contrary

What is an example of catatonic behaviour?

stupor, mutism, posting, excitement

How can schizophrenia symptoms be classified?

• Positive symptoms - changes or additions to persons typical behaviour, thought and feelings

• Negative symptoms - an absence of things that should be present normally

Positive schizophrenia symptoms

• hallucinations

• delusions

• disorganised thought and thinking

Kinds of hallucinations

• auditory

• tactile

• visual

• olfactory

• gustatory

• proprioceptive

Kinds of delusions

Delusions of:

• grandeur

• persecution

• reference

• erotomania

Negative symptoms of schizophrenia

• Cognitive impairment

• Apathy

• Blunting or incognicty of emotional response

• poverty of speech

What is the prodromal period of schizophrenia?

It refers to the early signs and symptoms of schizophrenia

• mainly negative symptoms, preceding the positive symptoms

7 As of negative symptoms

• Apathy

• Avolation

• Anergia

• Alognia

• Anhedonia

• Asociality

• Affetive flattening

• Impaired attention

Apathy

feelings of indifference - lack of goal orientated activity

Avolation

Lack of will or motivation

Anergia

Lack of energy, tiredness or sleepiness continually

Alogia

Lack of speech

Anhedonia

Inability to enjoy activities previously bringing pleasure - lack of sex drive

Asociality

Social withdrawal, disinterest in social engagement

Affective flattening

Blunting of emotions/lack of range of emotions and emotional expression

What are the cognitive symptoms of schizophrenia?

• Average IQ of 95 that may decrease after first episode

• A discrepancy between verbal and non-verbal communication

• Impaired tension

• Executive functioning - problem solving, response inhibition, planning

• Over inclusiveness

Liddle’s 3 symptoms model

• Reality distortion - hallucinations and delusions

• disorganisation - thought disorder, inappropriate affect

• psychomotor poverty - poverty of speech

Associated findings in the brain

• increased ventricular volume

• decreased volume of cortex

• more neurones with less connections

During auditory hallucinations, which area of the brain is active?

Broca’s area

Difference between schizophrenia and schizoaffective disorder

schizoaffective disorder is characterised by a prominent mood disorder (depression of bipolar)

Schizophrenia - male vs female

Equal risk

Onset of symptoms of schizophrenia - male vs female

Earlier onset in males than females

• Mean of 22 in males

• 26 in females

Lifetime incidence of schizophrenia

1-2/10,000 per year

Prevalence of schizophrenia

1%

Rural vs urban - schizophrenia risk

Risk is greater in urban populations (2 x higher)

What is the genetic heritability of schizophrenia

• Identical twins = 48 %

• Fraternal twins = 17%

• children = 13 %

• Parents = 6 %

What are the prenatal risk factors of schizophrenia?

• premature birth

• unwanted pregnancy

• rubella

• malnutrition

What are the obstetric or neonatal risk factors of schizophrenia?

• Obstetric complications

• low birth weight

• hypoxia

Early childhood risk factors of schizophrenia

• mixed handedness

• late milestones

What are precipitating factors for schizophrenia?

• Life events

• stress

• substance abuse (especially cannabis)

how is dopamine linked with psychosis?

Excess dopamine is linked to psychosis

Dopamine hypothesis

increased dopaminergic activity on D2 receptors in acute psychosis - excess striatal release of dopamine

Which dopamine pathway in the brain is associated with positive symptoms?

Mesolimbic pathway (due to increased DA activity)

Which dopamine pathway in the brain is associated with negative symptoms?

Mesocortical ( due to a decrease in DA activity)

Which pathways are affected by antipsychotic drugs?

• Nigrostriatal

• Tuberoinfundibular

Glutamate hypothesis

Has components of the dopamine hypothesises BUT includes impact of dysfunctional NDMA receptors and glutamate dysregulation

How do dysfunctional NDMA receptors relate to the negative symptoms of schizophrenia?

Dysfunctional NDMA receptors lowers glutamate transmission = negative symptoms

How does a decrease in glutamate transmission also relate to positive symptoms of schizophrenia?

Reduced glutamate transmission lowers GABA transmission = less inhibition of dopamine neurones

• This leads to an increase in dopamine release = positive symptoms

organic causes of psychosis

• Autoimmune conditions

• tumours

• parkinson’s, MND, MS

• HIV, meningitis, encephalitis

Timeline from onset of acute & transient psychotic disorders

Less than 2 weeks

• complete recovery usually within a few months

Which receptors do antipsychotics tend to antagonise?

D2 in the mesolimbic pathway (and other receptors unfortunately)

How are 1st and 2nd generation antipsychotics different in receptor antagonism?

BOTH target D2 receptors

• 1st gen = also target other receptors (muscarinic, alpha-1 and H-1)

• 2nd gen = higher affinity to 5-HT - 2 receptors = serotonin-dopamine antagonism

Examples of 1st gen antipsychotics

Chlorpromazine, haloperidol, perphenazine

Examples of 2nd gen antipsychotics

Risperidone, olanzapine

What drug is used in treatment resistant cases?

Clozapine - only to be used when 2 other antipsychotics, including at least one 2nd gen antipsychotic has failed/ not been tolerated

Main side effects of antipsychotics

• sedation

• weight gain

• involuntary movements

• QT prolongation

What are possible psychological treatments for schizophrenia?

Family therapy

CBTp

Trauma focus

Social treatment for schizophrenia

• housing support

• employment/educational support

• Community engagement