Schizophrenia and Research Methods

Vocabulary flashcards covering positive and negative symptoms, classification systems, diagnostic validity and reliability issues, and research methods related to schizophrenia.

Positive Symptoms

Symptoms experienced in addition to a person's normal behaviour, including hallucinations, delusions, thought broadcast, thought insertion, and disorganised speech.

Negative Symptoms

Symptoms that represent a loss or reduction of usual behaviour or abilities, including speech poverty, avolition, loss of emotion, catatonic behaviour, and social withdrawal.

Delusions

False beliefs that are firmly held despite being completely illogical, or for which there is no evidence.

Delusions of Persecution

A type of delusion involving the false belief that others want to harm, threaten, or manipulate you.

Delusions of Grandeur

A type of delusion involving the idea that you are an important, god-like individual with extraordinary powers, such as believing you are Jesus Christ.

Delusions of Control

A type of delusion where individuals believe they are under the control of an alien force that has invaded their mind or body, such as through spirits or implanted radio transmitters.

Hallucinations

Disturbances in perception that are false sensory experiences with no basis in reality, most commonly auditory (hearing voices) but also visual, olfactory, or tactile.

Speech Poverty (Alogia)

A negative symptom characterized by the inability to speak properly and a reduction in the quality and amount or frequency of speech, reflecting slowed or blocked thoughts.

Avolition

A negative symptom characterized by the reduction, difficulty, or inability to start and continue with goal-directed behaviour, often mistaken for apparent disinterest.

DSM-5

The Diagnostic and Statistical Manual of Mental Disorders (fifth edition), produced by the American Psychiatric Association and primarily used in the USA, which requires at least one positive symptom to diagnose schizophrenia.

ICD-10

The International Statistical Classification of Diseases and Related Health Problems (tenth revision), published by the World Health Organization and commonly used in Europe, where two or more negative symptoms are sufficient for a diagnosis of schizophrenia.

Reliability in Diagnosis

The consistency of diagnostic criteria, particularly inter-rater reliability, which measures the extent to which different psychiatrists reach the same diagnostic decision when independently assessing the same patient.

Validity in Diagnosis

The extent to which diagnostic criteria correctly identify individuals who actually have schizophrenia, avoiding misdiagnosis or underdiagnosis.

Criterion Validity

A method of assessing diagnostic validity by comparing different classification systems to see if they arrive at the same diagnosis for the same patient.

Co-morbidity

The simultaneous presence or co-occurrence of two or more distinct medical or psychological conditions in the same individual at the same time.

Symptom Overlap

The phenomenon where two or more distinct mental disorders share common symptoms, such as schizophrenia and bipolar disorder both featuring delusions and avolition.

Gender Bias in Diagnosis

A limitation in diagnosis where one gender is diagnosed more or less frequently due to clinician bias or differing social functioning, such as men being diagnosed at a ratio of $1.4:1$ compared to women since the 1980s.

Culture Bias in Diagnosis

A limitation in diagnosis where symptoms have different cultural meanings, leading clinicians from different backgrounds to misinterpret or overinterpret symptoms.

Cheniaux et al. (2009)

A study demonstrating poor criterion validity in schizophrenia diagnosis, finding that two psychiatrists assessing the same $100$ patients diagnosed $68$ using ICD-10 but only $39$ using DSM-5.

Buckley et al. (2009)

A study investigating co-morbidity in schizophrenia that found 50\text{\null}\% of patients had co-occurring depression, 47\text{\null}\% had substance abuse, 29\text{\null}\% had post-traumatic stress disorder, and 23\text{\null}\% had OCD.

Loring and Powell (1988)

A study demonstrating gender bias in diagnosis, finding that clinicians diagnosed 56\text{\null}\% of patients as schizophrenic when described as male or gender-unspecified, compared to 20\text{\null}\% when described as female.