Schizophrenia

Symptoms of Schizophrenia and psychosis

  • Positive symptoms (additional things that are abnormal)

    • Hallucinations: Perceptual experiences that occur in the absence of an external stimulus

      • Auditory hallucinations are most common in schizophrenia

      • In the general population sleep-related hallucinations (hypnogogic and hypnopompic) are not uncommon

    • Delusions: Beliefs that are firmly held and that cannot be changed by conflicting evidence

      • Must be unusual in a person's socio-cultural context

      • Persecutory delusions: Beliefs that one is being harmed or harassed by others

        • E.g. The government has put a chip in my brain and is listening to my thoughts

      • Delusions of reference: Beliefs that environmental cues are directed at oneself

        • E.g. Someone is sending me messages through the daily newspaper

      • Somatic delusions: Beliefs regarding health and organ functions

        • E.g. My body is decomposing while I am still alive

  • Negative symptoms (A subtraction of what we would normally hope to have)

    • Blunted affect (diminished emotional expression)

    • Anhedonia: Reduced pleasure or enjoyment in activities and events

    • Alogia: Diminished use of speech

    • Avolition: Reduction in self-initiated motivated action

    • Asociality: Lack of interest and engagement in social interactions specifically

  • Disorganised symptoms

    • Disorganised thought and speech: Tangential speech with loosened associations between concepts

    • Disorganised or catatonic behaviour

      • Disorganised behaviour: Strange or unusual patterns of goal-directed behaviour, resulting in difficulties in performing activities of daily living

        • Wearing too many clothes in summer and vice versa

        • Lack of self-care

        • Childlike behaviours and social withdrawal

      • Catatonia: A subtype of disorganised behaviour that involves dramatically reduced reactivity to the external world

        • Maintaining a rigid, inappropriate, or bizarre posture

        • A complete lack of verbal and/or motor responses

        • Repeated stereotyped movements, staring, grimacing

        • Echolalia: echoing of speech

  • Cognitive symptoms (the wore the cognitive symptoms the worse the quality of life)

    • Impairments in attention

    • Impairments in memory

    • Impairments in processing speed

  • Psychosis: Shorthand term that is often used to refer to positive and disorganised symptoms

    • May occur due to substance use

    • May occur in other psychological disorders

  • Schizophrenia: A psychological disorder that involves periods of psychosis

    • People with schizophrenia have additional symptoms including negative and cognitive symptoms

 

Diagnosis of Schizophrenia and related disorders


  • The DSM-5 refers to schizophrenia spectrum and other psychotic disorders (all have psychosis and psychosis-like experiences)

    • Schizophrenia: Symptoms must persist for at least 6 months

    • Schizoaffective disorder: Involves an additional simultaneous mood episode (either depression or mania)

    • Schizophreniform disorder: Shorter duration and potentially less functional impairment (1-6 months)

    • Brief psychotic disorder: Involves shorter duration (chronicity is an important consideration) (between 1 day and 1 month)

    • Delusional disorder: Involves delusional symptoms only (no Criterion 1 symptoms and no functional impairment)

    • Schizotypal personality disorder: Involves sub-threshold symptoms

      • Beliefs that are not so out there that they are impaired like people who experience delusions (e.g. They don't think the government has put a chip in their brain but they do generally believe the government is monitoring them extensively)

    • Substance/medication-inducted psychotic disorder


 

Epidemiology, course and aetiology of schizophrenia and related disorders

  • Lifetime prevalence of 0.5 to 1% of the world's population

  • Peak age of onset in late adolescence and early adulthood (typically 16-25 years)

    • Earlier for men than women on average

  • Rates are approximately equal in men and women but severity is worse in men on average


  • Schizophrenia is a chronic condition

    • Most commonly people with schizophrenia will have a number of severe 'acute' episodes of psychosis

    • Between episodes the severity of negative and cognitive symptoms are the best predictors of quality of life

    • 20% have an 'optimal' course of illness (can live independently, hold down a job, and have meaningful relationships)

    • Comorbid depressive and anxiety disorders are common in people with schizophrenia

  • High heritability indicates a strong genetic component (estimated around 80%)



  • Three separate genetic contributors:

    • De novo mutations: Completely new variations in the genetic code (present in 2% of the general population but 5% of people with schizophrenia

    • Rare alleles of high risk

      • A least 11 rare inherited copy number variations are associated with increased risk (risk increases between 2x and 60x)

      • Often associated with glutamate functioning (especially via the NMDA receptor)

    • Common alleles of low risk

      • At least 128 common polymorphisms account for approximately half of the genetic contribution to schizophrenia

  • Neuroanatomical dysfunction in schizophrenia

    • Enlarged ventricles

      • Indicates loss of brain cells

      • Enlargement correlated with severity of cognitive impairments


  • Demyelination

    • Less white matter integrity in schizophrenia

    • Some other diseases involving demyelination are linked with increased risk of psychosis


  • Environmental factors

    • Complications during birth involving hypoxia to the brain

    • Maternal immune response during pregnancy

    • Maternal malnutrition during pregnancy

    • Low socio-economic status

    • Living in urban areas

    • Latitude (higher rates further from the equator)

    • Season of birth (rates are higher for those born in winter/spring)

    • Fish consumption (lower rates in populations with higher fish intake)

  • Psychological factors

    • Life stressors

 

Treatment of schizophrenia and related disorders

  • Treatment is difficult and remission rates are low

  • Clinical recommendations suggest antipsychotic medication + adjunct psychological therapy

    • Therapy aimed at specific symptoms and dysfunctions

    • Medication shows efficacy for positive and disorganised symptoms

  • Chlorpromazine was the first antipsychotic (obliterated schizophrenia and every other cognitive function along with it)


  • Antipsychotics may exacerbate negative and cognitive symptoms overtime

    • 30% of people do not respond to them

 


  • Social skills training

    • Associated with better functional outcomes and lower relapse likelihood

  • Psychoeducation

  • CBT

  • Cognitive remediation therapy

    • Cognitive symptoms of schizophrenia directly