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Abnormal Psychology Unit 6: Schizophrenia Spectrum and Other Psychotic Disorders

Psychotic disorders involve a loss of contact with reality through delusions, hallucinations or disorganized thinking. Schizophrenia affects under 1% of people but causes great disability, and it is best understood through a diathesis-stress model combining genes, brain development and environment.

Covers: Positive, negative and disorganized symptoms, DSM-5-TR criteria for schizophrenia, Related psychotic disorders and their time rules, Genetic and prenatal risk factors, Dopamine, glutamate and brain structure, Family and social factors, including expressed emotion, Antipsychotic medication and psychosocial treatment

Study guide

Symptoms of schizophrenia fall into three groups. Positive symptoms are excesses or distortions of normal functioning: delusions (fixed false beliefs held despite evidence, such as persecutory, referential or grandiose delusions) and hallucinations (perceptions without a stimulus, most often auditory voices). Disorganized symptoms include disorganized speech, such as derailment or word salad, and grossly disorganized behavior. Negative symptoms are reductions in normal functioning: diminished emotional expression (flat affect), avolition (lack of motivation), alogia (poverty of speech), anhedonia and asociality. Negative symptoms are harder to treat and strongly predict poor functioning. Catatonia, a marked disturbance of movement such as stupor, rigid posturing or purposeless excitement, can occur in schizophrenia and in mood disorders and is listed as a specifier.

The DSM-5-TR requires at least two of five symptoms (delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, and negative symptoms) for a significant part of one month, and at least one must be delusions, hallucinations or disorganized speech. Continuous signs of disturbance must last at least six months, which can include prodromal or residual periods with milder symptoms, and functioning must drop markedly in work, relationships or self-care. Time rules separate related disorders. Brief psychotic disorder lasts at least one day but less than one month, followed by a full return to functioning. Schizophreniform disorder lasts at least one month but less than six. Delusional disorder involves one or more delusions for at least a month without the other symptoms of schizophrenia and with fairly intact functioning. Schizoaffective disorder combines a major mood episode with schizophrenia symptoms, plus at least two weeks of delusions or hallucinations without a mood episode.

Schizophrenia usually begins between the late teens and mid-30s, often slightly earlier in men. Lifetime prevalence is roughly 0.3% to 0.7%. Genetics play a large role. Irving Gottesman's summary of family studies showed that risk rises with genetic relatedness: about 1% in the general population, roughly 10% for a sibling or child of an affected person, and close to 50% for an identical twin. Since identical twins are not 100% concordant, environment also matters. Risk is raised by prenatal and birth factors such as maternal infection or malnutrition and obstetric complications, by older paternal age, by heavy cannabis use in adolescence, and by urban upbringing, migration and social adversity. Many genes of small effect contribute, consistent with a polygenic, diathesis-stress view.

The original dopamine hypothesis held that schizophrenia reflects too much dopamine activity, based on the fact that drugs blocking D2 receptors reduce psychosis and drugs like amphetamine that raise dopamine can cause it. The revised view proposes excess dopamine in the mesolimbic pathway, linked to positive symptoms, and too little in the mesocortical pathway to the prefrontal cortex, linked to negative and cognitive symptoms. The glutamate hypothesis adds that underactive NMDA glutamate receptors contribute, since NMDA blockers like PCP and ketamine produce both positive and negative symptoms. Brain imaging shows enlarged ventricles, reduced gray matter and reduced prefrontal activity (hypofrontality) on average. Socially, high expressed emotion in families (criticism, hostility and emotional overinvolvement) predicts relapse. The older idea of a schizophrenogenic mother has been rejected. Social causation and downward drift both help explain the link with poverty.

First-generation antipsychotics, such as chlorpromazine and haloperidol, block D2 receptors and reduce positive symptoms, but they often cause extrapyramidal side effects, which are movement problems such as muscle stiffness, tremors and restlessness, and, with long-term use, tardive dyskinesia, involuntary movements of the face and tongue that may be permanent. Second-generation antipsychotics, such as risperidone, olanzapine and clozapine, affect both dopamine and serotonin and cause fewer movement problems but more weight gain and metabolic effects. Clozapine is the most effective drug for treatment-resistant schizophrenia but requires blood tests because of a rare risk of agranulocytosis, a dangerous drop in white blood cells. Psychosocial treatments are essential: family psychoeducation to lower expressed emotion, cognitive-behavioral therapy for psychosis, social skills training, supported employment, assertive community treatment and coordinated specialty care for a first episode.

Key ideas

• Positive symptoms add experiences (delusions, hallucinations); negative symptoms remove normal ones (flat affect, avolition, alogia).
• Schizophrenia requires six months of disturbance, including at least one month of active symptoms.
• Duration separates brief psychotic disorder (under 1 month), schizophreniform disorder (1 to 6 months) and schizophrenia (6 months or more).
• Risk rises with genetic relatedness, but identical-twin concordance near 50% shows environment matters too.
• Excess mesolimbic dopamine is linked to positive symptoms, while low prefrontal dopamine and glutamate dysfunction relate to negative and cognitive symptoms.
• High expressed emotion in families predicts relapse, and family interventions reduce it.
• First-generation antipsychotics risk movement side effects; second-generation drugs risk metabolic side effects.

Formulas and rules

Common mistakes

• Confusing schizophrenia with dissociative identity disorder; schizophrenia does not mean 'split personality'.
• Calling negative symptoms 'bad' symptoms; negative means an absence of normal functions.
• Forgetting that the six-month total includes prodromal and residual phases, not six months of active psychosis.
• Saying antipsychotics cure schizophrenia; they reduce symptoms, mainly positive ones, and relapse is common if stopped.
• Blaming parents for causing schizophrenia; the schizophrenogenic mother theory is rejected, though family climate affects relapse.

Before the test, make sure you can

• Classify symptoms of a case as positive, negative, disorganized or catatonic.
• Apply the DSM-5-TR criteria and time rules to distinguish schizophrenia, schizophreniform, brief psychotic, delusional and schizoaffective disorders.
• Interpret family and twin risk data for schizophrenia.
• Explain the original and revised dopamine hypotheses and the glutamate hypothesis.
• Describe brain differences and prenatal risk factors linked to schizophrenia.
• Explain expressed emotion, social causation and downward drift.
• Compare first- and second-generation antipsychotics and describe key psychosocial treatments.

Words to know

Psychosis

A loss of contact with reality, shown by delusions, hallucinations or severely disorganized thinking.

Delusion

A fixed false belief that is held despite clear contrary evidence.

Hallucination

A perception that occurs without an external stimulus, most often hearing voices in schizophrenia.

Positive symptoms

Excesses or distortions of normal functioning, such as delusions and hallucinations.

Negative symptoms

Reductions in normal functioning, such as flat affect, avolition, alogia, anhedonia and asociality.

Avolition

A lack of motivation to start or persist in goal-directed activities.

Alogia

Poverty of speech, with brief, empty replies.

Catatonia

A marked disturbance of movement, such as stupor, rigid posturing or excessive purposeless activity.

Brief psychotic disorder

Psychotic symptoms lasting at least one day but less than one month, with a full return to functioning.

Schizophreniform disorder

Schizophrenia-like symptoms lasting at least one month but less than six months.

Schizoaffective disorder

A major mood episode together with schizophrenia symptoms, plus at least two weeks of delusions or hallucinations without a major mood episode.

Delusional disorder

One or more delusions lasting at least a month without other schizophrenia symptoms and with fairly intact functioning.

Dopamine hypothesis

The theory that dysregulated dopamine activity, especially excess in mesolimbic pathways, underlies psychotic symptoms.

Expressed emotion

A family climate of criticism, hostility and emotional overinvolvement that predicts relapse.

Downward drift

The idea that the disorder's effects cause people to move into lower socioeconomic conditions.

Tardive dyskinesia

Involuntary movements of the face, tongue and limbs that can follow long-term antipsychotic use.

Clozapine

A second-generation antipsychotic that is most effective for treatment-resistant schizophrenia and requires blood monitoring.

Assertive community treatment

A team-based approach that provides intensive, around-the-clock support for people with severe mental illness in the community.

Sample practice questions

30 more questions like these, from level 1 to 5, are in the practice set.