Schizophrenic Spectrum Disorders (College Board AP® Psychology): Study Guide

Positive & negative symptoms of schizophrenia

• Schizophrenia spectrum disorders are among the most severe psychological disorders

  • They typically emerge in early adulthood and often cause significant impairment

• Importantly, schizophrenia does not mean “split personality," but refers to a loss of contact with reality

• Symptoms may develop:

  • acutely (sudden onset)

  • chronically (gradual, long-term)

• Schizophrenia involves disturbances in one or more of five areas:

  • delusions

  • hallucinations

  • disorganized thinking/speech

  • disorganized behaviour

  • negative symptoms

• Symptoms of schizophrenia are divided into positive and negative symptoms:

  • Positive symptoms refer to excesses or distortions in behavior, thought, or perception

    • E.g. things that are present that should not be

  • Negative symptoms refer to deficits or reductions in behavior, thought, or emotion

    • E.g. the absence of things that should normally be present

  • This distinction matters clinically because positive and negative symptoms often respond differently to treatment

Positive symptoms

Delusions

• Delusions are false beliefs that are held despite clear contradictory evidence

  • Two common types include:

    • delusions of persecution: the belief that one is being watched, followed, plotted against, or persecuted by others

      • E.g. believing the CIA is monitoring all your movements and planning to harm you

    • delusions of grandeur: the belief that one has exceptional abilities or importance

      • E.g. believing you are a world leader

• Other delusion types include:

  • ideas of reference: believing random events have special personal meaning

  • thought insertion: believing thoughts are being placed in one's mind by an outside force

Hallucinations

• Hallucinations are false perceptions that occur without any external stimulus

  • Hallucinations may involve one or more senses:

    • Auditory hallucinations are the most common, particularly hearing voices that others cannot hear

      • E.g. hearing voices making derogatory comments

    • Visual hallucinations: seeing things that are not there

      • E.g. seeing spiders or faces

• Hallucinations feel completely real to the person experiencing them; they are not imagined or chosen

Disorganized thinking or speech

• Disorganized thinking manifests as incoherent or illogical thought patterns

  • In speech, disorganized thinking produces word salad

    • These are strings of words that are grammatically connected but make no meaningful sense, or that jump from one unrelated topic to another

      • E.g. "Tuesday is flying blue because my mother's hat was president of the sink"

  • People with disorganized thinking often use neologisms

    • These are made-up words that only have meaning to themselves

• Individuals with this symptom may also string together words that rhyme regardless of meaning (clang associations)

Disorganized motor behavior

• Disorganized motor behavior involves unusual, uncontrolled, or unpredictable physical movement or demeanor

  • It can manifest as catatonic excitement, which is bizarre, purposeless motor activity

    • E.g. making strange postures; rocking; grimacing; agitated purposeless movement

  • It manifests as a negative symptom when it presents as catatonic stupor

    • This is the absence of movement or response

Negative symptoms

• Negative symptoms represent the absence or reduction of behaviors that are normally present:

  • Flat affect: significantly reduced or absent emotional expression

    • The person speaks in a monotone voice, has an expressionless face, and shows little emotional response to events

  • Alogia: poverty of speech, which involves greatly reduced speech output

    • The person may give brief replies that convey little information

  • Avolition: reduced motivation and inability to initiate goal-directed activities

    • The person may sit for hours doing nothing

  • Anhedonia: inability to experience pleasure from activities that were previously enjoyable

  • Catatonic stupor: a state of motor immobility

    • The person may remain motionless for long periods in unusual positions

• Negative symptoms are often more disabling in the long term, as they significantly impair daily functioning and are harder to treat than positive symptoms

Causes of schizophrenia

Biological & genetic causes

• Schizophrenia is best explained by a combination of genetic, biological, and environmental factors, rather than a single cause

Genetic factors

• Schizophrenia runs strongly in families:

  • The general population risk is approximately 1%

  • For a first-degree relative, the risk rises to approximately 10%

  • Having an identical twin it raises the risk to approximately 50%

• Higher concordance in identical twins supports a genetic component, but rates below 100% show that environmental factors are also necessary

The dopamine hypothesis

• This theory proposes that schizophrenia involves dysregulation of dopamine, particularly excess activity linked to positive symptoms

• The following evidence supporting the dopamine hypothesis:

  • Antipsychotic drugs that block dopamine receptors reduce positive symptoms

  • L-Dopa (a drug that increases dopamine levels) can produce schizophrenia-like symptoms

  • Stimulant drugs like amphetamines, which increase dopamine activity, can trigger psychotic episodes

• However, dopamine alone does not fully explain schizophrenia, as other neurotransmitters (e.g. glutamate) are also implicated

Prenatal factors

• Early biological influences increase risk of schizophrenia:

  • children born to mothers who contracted certain viral infections (e.g. influenza) during the second trimester show higher rates of schizophrenia

  • malnutrition, prenatal stress, or birth complications are also implicated

• These factors may disrupt early brain development

Brain structure

• Research shows differences in the brains of individuals with schizophrenia. They tend to have:

  • enlarged ventricles, suggesting reduced brain tissue

  • altered connectivity in areas involved in cognition and emotion

Environmental & psychosocial factors

• Not all psychologists accept a purely biological account, as environmental influences also contribute to the development of schizophrenia:

  • Psychosocial stressors: life stress may trigger symptoms in vulnerable individuals (diathesis-stress model)

  • Double bind theory: contradictory communication in early environments may contribute to disordered thinking