Source: Abnormal Psychology textbook (University of Florida)
Tags: schizophrenia, psychosis, positive symptoms, negative symptoms, cognitive deficits, delusions, hallucinations, DSM-5, diagnosis, prognosis, schizophrenia spectrum
Difficulty: Intermediate | Prerequisites: Basic understanding of psychological disorders and DSM classification.
Schizophrenia is one of the most severe and chronic mental disorders, sitting at the centre of the "schizophrenia spectrum" of psychotic conditions. This chapter covers how the disorder presents, how it is diagnosed, and what outcomes look like over time. If you have covered mood disorders and the general structure of the DSM-5, you have what you need to follow along. The material here is dense and detail-heavy, so the notes below are split into three parts: symptoms and diagnosis (this document), causes and theories (Part 2), and treatment (Part 3).
Schizophrenia involves a loss of contact with reality (psychosis) and is defined by five symptom domains: delusions, hallucinations, disorganised thought/speech, disorganised or abnormal motor behaviour, and negative symptoms such as restricted affect. Diagnosis under the DSM-5 requires at least two of these symptoms for six months, with significant functional impairment. The disorder is chronic but can stabilise over time, and women tend to have a better prognosis than men.
Psychosis
The inability to distinguish what is real from what is not. It can take many forms and is the core diagnostic feature of schizophrenia. In simple terms, this means the person's perception of reality is fundamentally disrupted.
Schizophrenia spectrum
A framework reflecting five domains of symptoms that define psychotic disorders, varying in number, severity, and duration to distinguish different levels of the disorder. Think of it as a continuum: people can show all or only some psychotic features, and the presentation varies widely between individuals.
Positive symptoms
Overt expressions of unusual perceptions, thoughts, and behaviours that are "added" to normal experience. These include delusions, hallucinations, disorganised speech, and disorganised or abnormal motor behaviour. In simple terms, these are things present in the person's experience that should not be there.
Negative symptoms
The loss or reduction of certain qualities, such as emotional expression, motivation, and social engagement. Think of it as something being taken away from the person's normal functioning.
Delusions
Fixed beliefs that are not amenable to change in light of conflicting evidence (DSM-5 definition). These are ideas an individual holds as true despite being highly unlikely or impossible. In simple terms, these are unshakeable false beliefs, distinct from ordinary self-deceptions because the person cannot recognise their belief is unreasonable.
Hallucinations
Unreal perceptual experiences that can involve any of the senses. In schizophrenia, they tend to be more frequent, persistent, complex, and bizarre than hallucinations caused by sleep deprivation or intoxication. Think of it as the brain generating sensory input that has no external source.
Formal thought disorder
Disorganised thinking characteristic of schizophrenia, observable through the person's speech. In simple terms, the person's train of thought goes off the rails and their speech stops making sense.
Loose associations (derailment)
The tendency to slip from one topic to another unrelated topic with little coherent transition. Think of it as a conversation that keeps changing direction without any connecting thread.
Neologisms
Made-up words that carry meaning only for the person who coined them.
Clangs
Word associations based on the sound of the word rather than its meaning.
Word salad
Speech so disorganised it is completely incoherent.
Catatonia
Disorganised behaviour reflecting unresponsiveness to the environment. Ranges from lack of response to instructions (negativism) to rigid or bizarre postures, to complete absence of verbal or motor responses (mutism).
Catatonic excitement
Purposeless and excessive motor activity for no apparent reason. The person may voice delusions or hallucinations, or be incoherent.
Restricted affect (flat affect)
Severe reduction or absence of emotional expression. The person may show fewer facial expressions, avoid eye contact, and speak in a flat, monotone voice.
Anhedonia
Loss of the ability to experience pleasure. Commonly reported by people with schizophrenia, though lab studies suggest they may experience positive affect internally even when it is not expressed outwardly.
Avolition
Inability to initiate or persist at common, goal-directed activities. The person appears physically slowed, unmotivated, and may neglect personal hygiene.
Asociality
Lack of desire to interact with other people. Should only be diagnosed when the individual has access to welcoming family and friends but still shows no interest in socialising.
Dementia praecox
The original label given to schizophrenia by Emil Kraepelin, who believed the disorder resulted from premature deterioration of the brain and was progressive, irreversible, and chronic.
Prodromal symptoms
Symptoms appearing before the acute phase of the disorder. The person may be withdrawn, hold unusual (but not delusional) beliefs, have odd perceptual experiences, and speak tangentially but remain coherent.
Residual symptoms
Symptoms remaining after the acute phase, similar in character to prodromal symptoms.
Self-deceptions differ from delusions: self-deceptions can plausibly happen, do not preoccupy the person, and the person recognises the idea is unreasonable. People with delusions do not.
Delusions can be simple and transient or complex and elaborate.
Content varies across cultures. Odd or impossible beliefs tied to cultural norms are generally not considered delusions unless extreme.
The DSM-5 shifted the definition from "erroneous beliefs" to "fixed beliefs that are not amenable to change in light of conflicting evidence," because establishing that a belief is fully false can be very difficult.
Types of delusions:
Persecutory: Belief that one is being watched or tormented by known or unknown people.
Delusion of reference: Belief that random events or others' comments are directed specifically at them.
Grandiose: Belief that one is a special being or possesses special powers.
Thought insertion: Belief that one's thoughts are being controlled by outside forces.
Common in sleep-deprived or intoxicated people, but those are occasional and do not interfere with function.
In schizophrenia, hallucinations are more frequent, persistent, complex, bizarre, and entwined with delusions.
Clinicians must understand hallucinations in their cultural context to avoid misdiagnosis.
Types of hallucinations:
Auditory: Hearing voices. The most common type.
Visual: Seeing things that are not there (usually accompanied by auditory hallucinations).
Tactile: Perception that something is happening to the outside of the body.
Somatic: Perception that something is happening to the inside of the body.
Loose associations (derailment): slipping between unrelated topics.
May answer questions with unrelated or barely related comments.
Speech can become completely incoherent (word salad).
May create neologisms or use clangs.
May repeat the same word or statement repeatedly.
Men tend to show more severe language deficits than women with schizophrenia, possibly because women can control language with both hemispheres while men rely primarily on one.
Can frighten others; may be unpredictable and untriggered.
Behaviours may occur in response to hallucinations or delusions.
Difficulty organising daily routines due to impaired attention and memory.
May engage in socially unacceptable behaviour, appear dishevelled, or wear inappropriate clothing for the weather.
Catatonia ranges from negativism to bizarre postures to mutism.
Catatonic excitement involves purposeless, excessive motor activity.
Involve the loss of certain qualities rather than the addition of unusual ones.
In schizophrenia, the key negative symptoms are restricted affect and avolition/asociality.
Strong negative symptoms are more associated with poor outcomes than strong positive symptoms.
Negative symptoms are more persistent and more difficult to treat than positive symptoms.
Less prominent in other psychotic disorders.
Fewer facial expressions, avoidance of eye contact, reduced use of gestures.
Flat voice with little change in emphasis, intonation, rhythm, tempo, or loudness.
People with schizophrenia report significant anhedonia, yet lab tests show they experience similar levels of positive affect as others internally. This discrepancy may reflect limitations of self-report questionnaires or co-occurring depression.
Physical slowness, apparent lack of motivation.
May sit around all day doing almost nothing; neglect hygiene and grooming.
Can manifest as asociality (lack of desire to interact).
Social withdrawal may partly result from stigma rather than the disorder itself.
Deficits in attention, memory, processing speed, and working memory.
Difficulty filtering relevant information from irrelevant input, both internal and environmental.
These deficits may contribute to hallucinations, delusions, disorganised thought and behaviour, and avolition.
Relatives may show similar cognitive deficits to a lesser degree, even without symptoms of schizophrenia.
Many people show cognitive deficits before developing acute symptoms.
Cognitive symptoms do not improve over time or with treatment.
Cognitive deficits may contribute to the development of other symptoms and strongly add to the overall disability.
Recognised as a psychological disorder since the early 1800s.
Emil Kraepelin labelled it "dementia praecox," viewing it as progressive, irreversible, and chronic.
Eugen Bleuler disagreed, introduced the term "schizophrenia," and believed the disorder involved a splitting of usually integrated psychic functions (associations, thoughts, emotions). He argued symptoms result from breaks in the associations among thought, language, memory, and problem solving.
Must show two or more symptoms of psychosis, at least one of which must be delusions, hallucinations, or disorganised speech.
Symptoms must be consistently and acutely present for at least one month (the acute phase).
Total symptoms must persist for at least six months to a degree that impairs social or occupational functioning.
Symptoms cannot be attributable to a substance, medical disease, or mood disorder.
If catatonia is present, it is specified in the diagnosis.
During the six months before and after the active phase, the individual may show mostly negative symptoms with milder positive symptoms (prodromal and residual phases).
Odd behaviour and asociality can resemble autism.
Key difference: hallucinations or delusions must be present in schizophrenia, and social interaction deficits in autism begin early in development.
One of the most severe and debilitating mental disorders.
Symptoms and impairments usually last for many years, even with treatment.
Once hospitalised, a person is more likely to be hospitalised again.
Shorter life expectancy; higher rates of infectious and circulatory diseases (reasons unclear).
Rather than continuous deterioration, people tend to stabilise within 5 to 10 years, showing fewer relapses and regaining a moderately good level of functioning.
Women tend to have a better prognosis: hospitalised less often and for shorter periods, milder symptoms between active phases, better social adjustment, and better prior histories (more likely to have completed education, married, developed social skills).
Later onset in women (late twenties to early thirties) compared to men (late teens to early twenties) may partly explain the difference.
Women show fewer cognitive deficits; oestrogen may regulate dopamine and be protective.
Males show greater brain structure abnormalities; slower brain development in males may increase vulnerability to abnormal development and in-utero insults.
In both sexes, functioning tends to improve with age, possibly related to declining dopamine levels.
Culture plays a strong role.
Schizophrenia tends to be more benign in developing countries, where broader and closer family networks share the burden of care, and there is generally less hostility, criticism, and overinvolvement directed at the affected person.
Students often think "positive" and "negative" symptoms refer to good and bad outcomes. They do not. "Positive" means something is added (hallucinations, delusions), and "negative" means something is taken away (emotion, motivation).
Students sometimes equate schizophrenia with "split personality." Bleuler's "splitting" referred to the fragmentation of thought, emotion, and association, not multiple personalities.
It is a common error to assume cognitive deficits improve with medication. They generally do not.
Students often overlook that asociality should only be diagnosed when the person has access to welcoming social contact but still shows no interest. Social withdrawal driven by stigma is a different matter.
⚠️ Know the five symptom domains of the schizophrenia spectrum and be able to give examples of each.
⚠️ Be able to distinguish positive from negative symptoms and explain why negative symptoms predict poorer outcomes.
⚠️ Understand the DSM-5 diagnostic criteria, including the time requirements (one month acute, six months total).
⚠️ Know the difference between prodromal, acute, and residual phases.
⚠️ The shift in the DSM-5 definition of delusions from "erroneous beliefs" to "fixed beliefs not amenable to change" is a commonly tested detail.
⚠️ Gender differences in onset, prognosis, and cognitive deficits are frequently examined.
True or False: Positive symptoms are called "positive" because they have a good prognosis. False. They are called positive because they represent additions to normal experience (e.g. hallucinations).
Fill in the blank: The DSM-5 requires symptoms to be present for at least ______ months with at least ______ month of acute symptoms. Six months total; one month acute.
True or False: Cognitive deficits in schizophrenia typically improve with antipsychotic medication. False. They generally do not improve over time or with treatment.
Fill in the blank: ______ refers to speech so disorganised it is completely incoherent. Word salad.
True or False: Women with schizophrenia tend to have an earlier age of onset than men. False. Women typically have a later onset (late twenties/early thirties vs. late teens/early twenties for men).
Q: What are the five symptom domains of the schizophrenia spectrum?
A: Delusions, hallucinations, disorganised thought (speech), disorganised or abnormal motor behaviour, and negative symptoms (restricted affect/avolition).
Q: How do delusions differ from ordinary self-deceptions?
A: Self-deceptions involve ideas that could plausibly happen, the person is not preoccupied with them, and the person can recognise the idea is unreasonable. People with delusions cannot recognise their belief is unreasonable and are often preoccupied with it.
Q: Why did the DSM-5 change the definition of delusions from "erroneous beliefs" to "fixed beliefs that are not amenable to change in light of conflicting evidence"?
A: Because it is highly difficult to establish the fully false nature of a belief, particularly when cultural context is considered.
Q: Explain how cognitive deficits might contribute to the development of hallucinations and delusions.
A: Cognitive deficits impair the ability to filter relevant from irrelevant information. The person struggles to determine where information is coming from (internal vs. external). Delusions and hallucinations may develop as the person tries to make sense of the overwhelming thoughts and perceptions bombarding their consciousness.
Q: Why do women with schizophrenia tend to have a better prognosis than men?
A: Women typically have a later age of onset (allowing more time to develop social skills, education, and relationships), show fewer cognitive deficits, and may benefit from the protective effects of oestrogen on dopamine regulation. Males also show greater brain structural abnormalities.
This material connects to mood disorders (Chapter on depression/bipolar), since delusions and hallucinations also appear in those conditions, typically with mood-congruent content. The dopamine hypothesis introduced here links directly to the neurotransmitter content in biological bases of behaviour. The sociocultural factors section ties into cross-cultural psychology and the importance of cultural competence in clinical assessment.
schizophrenia, psychosis, schizophrenia spectrum, positive symptoms, negative symptoms, cognitive deficits, delusions, hallucinations, auditory hallucinations, visual hallucinations, tactile hallucinations, somatic hallucinations, persecutory delusions, grandiose delusions, delusion of reference, thought insertion, formal thought disorder, loose associations, derailment, word salad, neologisms, clangs, catatonia, catatonic excitement, restricted affect, flat affect, anhedonia, avolition, asociality, DSM-5 criteria, dementia praecox, Kraepelin, Bleuler, prodromal symptoms, residual symptoms, prognosis, gender differences in schizophrenia, abnormal psychology chapter 8