*Schizophrenia

2. Schizophrenia

2.1 Definition

  • Schizophrenia is classified as a psychotic disorder characterized by severe disturbances in various domains:

    • Thinking

    • Speech

    • Perception

    • Emotion

    • Behavior

  • Term Origin: Introduced by Eugen Bleuler in 1911, the term means "split mind," which refers not to multiple personalities but to a disconnection between thought, emotion, and language.

  • Prevalence: Approximately 1% of the global population is affected by schizophrenia, with a slightly higher incidence noted in Canada.

2.2 Cognitive Features

  • Disorganized Thinking characterized by:

    • Loose associations (inability to form logical connections between thoughts)

    • Word salad (incoherent mixture of words)

    • Distractibility (inability to focus or concentrate)

2.3 Behavioral Features

  • Common behavioral characteristics include:

    • Withdrawal from social interactions

    • Neglecting self-care

    • Disorganized or bizarre behavior

2.4 Emotional Features

  • Emotional disturbances often include:

    • Blunted affect (a reduction in the intensity of emotional expression)

    • Flat affect (absence of emotional expression)

    • Inappropriate affect (emotional responses that do not match the situation)

2.5 Perceptual Features

  • Hallucinations, primarily auditory, where individuals hear voices or sounds that do not exist.

  • There can also be visual or tactile hallucinations, which may be experienced as extremely real.

2.6 Delusions

  • Defined as false beliefs which may include:

    • Persecution: The belief that others are conspiring to harm the individual.

    • Grandeur: The belief in possessing extraordinary abilities or identities, or having a special mission.

2.7 Disorganized Thought & Language

  • Symptoms may manifest as:

    • Strange word usage or neologisms

    • Rhyme-based associations

    • Illogical statements

2.8 Historical Subtypes of Schizophrenia (Removed in DSM-5)

  • Historically classified into subtypes that are no longer used due to poor reliability:

    • Paranoid

    • Disorganized

    • Catatonic: characterized by waxy flexibility, stupor, and rigid postures.

    • Undifferentiated

  • The current DSM-5 framework focuses on symptom dimensions rather than specific subtypes.

3. Type I vs Type II Schizophrenia

3.1 Type I (Positive Symptoms)

  • Includes symptoms such as:

    • Hallucinations

    • Delusions

    • Disorganized speech

    • Thought disorder

  • Prognosis: Better, typically with a sudden onset and a favorable response to medication.

  • Type I schizophrenia is often associated with normal functioning prior to the onset of symptoms.

3.2 Type II (Negative Symptoms)

  • Symptoms include:

    • Flat/blunted affect

    • Loss of motivation

    • Social withdrawal

    • Poverty of speech

  • Prognosis: Worse, usually with a gradual onset and linked to structural brain abnormalities.

4. Evidence for Genetic & Neurological Factors

4.1 Genetic Predisposition

  • The risk of developing schizophrenia is significantly influenced by genetic relatedness:

    • Concordance Rates:

    • Identical twins: 48%

    • Fraternal twins: 17%

    • Siblings: 10%

    • Child of one schizophrenic parent: 13%

    • General population: 1%

4.2 Adoption Studies

  • Evidence from adoption studies shows that children of biological parents with schizophrenia have a higher risk of developing the disorder, even when raised in non-schizophrenic adoptive households.

4.3 Biological Mechanism

  • While dopamine is a noted factor, it is not the sole influencer of the disorder. Other unidentified factors may also contribute to its onset and progression.