Schizophrenia - DSM-5

Diagnostic Criteria

A) 2+ symptoms, present for a significant portion of time during 1-month period (or less if successfully treated). one of the symptoms must be delusions, hallucinations, or disorganised speech.

1. delusions

2. hallucinations

3. disorganised speech (derailment, incoherence, tangentiality)

4. grossly disoragnised/catatonic behaviour

5. negative symptoms (diminished emotional expression, avolition, etc.)

B) for significant portion of the time since onset of disturbance, level of functioning in 1+ major areas has markedly decreased from the level achieved before onset (if kid/teen, can also be failure to achieve expected level of functioning)

C) continuous signs of disturbance persist for 6+ months. must include at least one month of symptoms meeting criteria A, and may include periods of prodromal / residual symptoms. during these periods, may only have negative symptoms or 2+ criteria A symptoms in reduced form

D) can’t be schizoaffective disorder or depressive / bipolar disorder w/ psychotic features, bc either 1) no major depressive / manic episodes have occurred concurrently w/ active-phase symptoms or 2) if mood episodes have happened during active-phase symptoms, they were present for a minority of the total duration of active + residual periods of illness

E) disturbance can’t be attributed to physiological effects of a substance or another medical condition

F) if there’s a history of autism or communication disorder w/ childhood onset, additional schizophrenia diagnosis can only be made if prominent delusions / hallucinations (+ other required symptoms) are also present for 1+ month

Diagnostic Features

• presentation varies significantly between people bc schizophrenia is a heterogenous clinical syndrome

• residual symptoms characterised by mild / subthreshold forms of hallucinations / delusions

• social withdrawal is often the first sign of the disorder

• mood symptoms + full mood episodes are common

• must assess cognition, depression, + mania symptom domains to distinguish between schizophrenia spectrum + other psychotic disorders

• prodromal / residual period may include: unusual / odd beliefs not of delusional proportions (eg: magical thinking), unusual perceptual experiences (eg: sensing presence of unseen person), understandable but vague speech, behaviour that is unusual but not grossly disorganised

Associated Features

• may display inappropriate affect, dysphoric mood that looks like depression / anxiety / anger, disturbed sleep pattern, & lack of interest in eating / food refusal

• depersonalisation, derealisation, & somatic concerns, sometimes to the point of delusion

• anxiety + phobias v common

• cognitive deficits are common (memory issues, language function, processing speed, social cognition, sensory processing, inhibitory capacity, attention deficits)

• some w/ psychosis lack insight or awareness — can include unawareness of symptoms + may be present during entire illness course. is typically a symptom itself, called anosognosia

  • anosognosia: most common predictor of treatment nonadherence; predicts higher relapse rates, high # of involuntary treatments, worse psychosocial function, aggression, & poorer illness course

• hostility + aggression may occur, tho spontaneous assault is rare. more frequent in younger men + people w/ history of violence, treatment nonadherence, substance abuse, & impulsivity

• differences in cellular architecture, white matter connectivity, & grey matter volume in parts of brain

• reduced overall brain volume + increased brain volume reduction w/ age

Prevalence

• lifetime: .3 - .7%

• overall no difference in prev. between sexes

Development + Course

• psychotic features usually start between late teens + mid-30s; onset before teens is rare

• peak onset: early-to-mid 20s in M; late 20s in W

• onset can be fast or slow, but is usually gradual: social withdrawal, emotional + cognitive changes → deteriorating role functioning

• ½ display depressive symptoms

• prognosis influenced by duration + severity of illness, + sex

  • M have more prominent negative symptoms, cognitive impairment, & worse functional outcomes than W

• sociocognitive deficits may manifest during development + precede psychosis → stable impairments in adulthood

• most people remain vulnerable to psychotic symptoms + a chronic course is common, but many people have periods of remission or recovery

• psychotic experiences tend to decrease in late life

• essential features of schizophrenia are same in childhood, but more difficult to make diagnosis

  • delusions + hallucinations may be less elaborate

  • visual hallucinations are more common

  • disorganised speech + behaviour may be due to another more common disorder

• childhood-onset cases tend to look like poor-outcome adult cases (gradual outcome, prominent negative symptoms)

• late-onset (eg: after 40) is overrepresented by W + often characterised by predominant psychotic symptoms w/ preservation of affect + social functioning — can still meet diagnostic criteria

Environmental Risk Factors

• season of birth linked to incidence: late winter / early spring, summer for deficit form

• risk may be higher for kids growing up in urban environment, refugees, some migrant groups, + socially oppressed groups facing discrimination

• social deprivation / adversity, socioeconomic factors → higher rates

• severity of positive-negative symptoms correlated w/ severity of adverse childhood experiences

• higher rates in some racial + ethnic groups when they live in areas w/ lower proportions of people from same group

Genetic Risk Factors

• liability inherited w/ risk alleles

• most w/ diagnosis have no family history of psychosis

• pregnancy + birth complications w/ hypoxia, + higher paternal age → higher risk

• some prenatal + perinatal adversities linked: stress, infection, malnutrition, maternal diabetes, + other medical conditions

Culture-Related Diagnostic Issues

• form + content vary across cultures

  • proportion of visual + auditory hallucinations

  • content of delusions + hallucinations, + level of assoc. fear

• must consider cultural + socioeconomic factors: ideas that are delusional in one culture may be commonly held in another

Functional Consequences

• 5 - 6% die by suicide

• 20% attempt suicide at least once

• many more experience suicidal ideation

• risk factors for suicidality: depressive symptoms, hopelessness, being unemployed, period after psychotic episode or hospital discharge, # of psychiatric admissions, closeness to illness onset, older age at illness onset, poor adherence to treatment, male sex, higher IQ

• more severe reading deficits than predicted by cognitive impairments

• educational progress + keeping job often impaired by avolition or other symptoms

• most are employed at a lower level than their parents

• most (esp. men) don’t marry + have limited social contacts outside family

Differential Diagnoses

• major depressive or bipolar disorder w/ psychotic or catatonic features

• schizoaffective disorder

• schizophreniform disorder + brief psychotic disorder

• delusional disorder

• schizotypal personality disorder

• obsessive-compulsive disorder + body dysmorphic disorder

• post-traumatic stress disorder

• autism spectrum disorder + communication disorders

• other mental disorders associated w/ a psychotic episode

• substance / medication-induced psychotic disorder

Differential Diagnosis: Major Depressive or Bipolar Disorder With Psychotic or Catatonic Features

depends on temporal relationships between mood disturbance + psychosis, + severity of depressive / manic symptoms. if delusions / hallucinations happen exclusively during depressive / manic episode, it’s depressive / bipolar disorder w/ psychotic features.

Differential Diagnosis: Schizoaffective Disorder

requires major depressive episode or manic episode that happens at same time as active-phase symptoms + that mood symptoms are present for majority of total duration of active periods

Differential Diagnosis: Schizophreniform Disorder + Brief Psychotic Disorder

both have shorter durations than schizophrenia. schizophreniform symptoms are present less than 6 months; brief psychotic disorder symptoms are present between 1 day - 1 month

Differential Diagnosis: Delusional Disorder

only delusions are present in delusional disorder. other symptoms characteristic of schizophrenia are missing

Differential Diagnosis: Schizotypal Personality Disorder

has subthreshold symptoms assoc. w/ persistent personality features

Differential Diagnosis: Obsessive-Compulsive Disorder + Body Dysmorphic Disorder

people w/ OCD + BDD may have poor / absent insight + preoccupations may reach delusional proportions, but will have other symptoms like obsessions, compulsions, hoarding, body-focused repetitive behaviours, or preoccupations w/ appearance. will lack other schizophrenia symptoms

Differential Diagnosis: Post-Traumatic Stress Disorder

flashbacks may have hallucinatory quallity + hypervigilance may become paranoia, but traumatic event + symptoms related to reliving / reenacting event are required for PTSD

Differential Diagnosis: Autism Spectrum Disorder + Communication Disorders

may have symptoms resemblling psychotic episode, but distinguished by deficits in social interaction w/ repetitive + restricted behaviours, or other cognitive + communication deficits. must have symptoms meeting full schizophrenia criteria w/ prominent hallucinations / delusions for at least 1 month for comorbid diagnosis

Differential Diagnosis: Other Mental Disorders Associated With a Psychotic Episode

schizophrenia only diagnosed when psychotic episode is persistent + can’t be attributed to the effects of another medical condition or substance. people w/ delirium or major / minor neurocognitive disorder may present w/ psychotic symptoms, but they’d have temporal relationship to onset of cognitive changes consistent w/ those disorders

Differential Diagnosis: Substance / Medication-Induced Psychotic Disorder

may present w/ symptoms metting criterion A, but can usually be distinguished by chronological relationship of substance use to onset, + remission of psychosis in absence of substance use

Comorbidity

• high rates of comorbidity w/ substance-related disorders

• over ½ of people w/ schizophrenia have tobacco use disorder

• anxiety disorders

• OCD + panic disorder occur more frequently in people w/ schizophrenia than genpop

• schizotypal personality disorder / paranoid personality disorder may precede schizophrenia onset

• life expectancy reduced bc of assoc. medical conditions

• weight gain, diabetes, metabolic syndrome, & cardiovascular + pulmonary disease more common than in genpop

• poor engagement in health maintenance behaviours increases risk of chronic disease, but other disorder factors (inc. meds, lifestyle, smoking, & diet) may contribute

• shared vulnerability for psychosis + medical conditions may explain some medical comorbidity