Schizophrenia Spectrum and Other Psychotic Disorders

1. Core Idea

These disorders are defined by abnormalities in one or more of 5 major psychotic domains.

2. Delusions

Definition

Delusions = fixed false beliefs not changed by evidence.

Delusions of Loss of Control

Usually considered bizarre.

Cultural Caution

Some beliefs may seem delusional in one culture but may be normal religious/cultural beliefs in another.

Trauma-Related Caution

People exposed to:

• torture
• political violence
• discrimination

may have intense fears that look persecutory, but may actually reflect trauma, not delusions.

3. Hallucinations

Definition

Hallucinations = perception-like experiences without external stimulus.

They are:

• vivid
• clear
• experienced like real perception
• not under voluntary control

Most Common in Schizophrenia

Auditory hallucinations

Usually heard as voices:

• familiar or unfamiliar
• separate from one’s own thoughts

These can be normal, so do not automatically diagnose psychosis.

4. Disorganized Thinking / Speech

Definition

Usually inferred from speech.

Cultural / Language Warning

Disorganized speech may be misjudged if:

• examiner and patient speak different languages
• interpreter errors occur
• glossolalia (“speaking in tongues”) is present
• possession trance is culturally accepted

These do not equal psychosis unless other psychotic features are present.

5. Grossly Disorganized or Abnormal Motor Behavior

Definition

Behavior can range from:

• childish silliness
• bizarre behavior
• unpredictable agitation
• inability to perform daily activities

6. Catatonia

Definition

Catatonia = marked decrease in reactivity to environment.

7. Negative Symptoms

These are especially important in schizophrenia.

8. Spectrum of Disorders in This Chapter

The chapter is arranged from:

• less severe / limited symptoms
• shorter duration disorders
• full schizophrenia spectrum disorders
• psychosis due to substances/medical causes

9. Schizotypal Personality Disorder

Main Features

10. Delusional Disorder

Key Feature

At least 1 month of delusions with no other major psychotic symptoms

11. Brief Psychotic Disorder

Duration

More than 1 day but remits by 1 month

12. Schizophreniform Disorder

Key Feature

Symptoms are like schizophrenia but duration is less than 6 months.

Also:

• no required functional decline

13. Schizophrenia

Duration Rule

Total illness duration at least 6 months

Includes:

• at least 1 month active-phase symptoms

14. Schizoaffective Disorder

Core Idea

Mood episode + schizophrenia-type symptoms occur together

BUT there must also be:

At least 2 weeks of delusions or hallucinations without prominent mood symptoms

15. Substance/Medication-Induced Psychotic Disorder

Cause

Psychosis due to:

• substance of abuse
• medication
• toxin exposure

16. Psychotic Disorder Due to Another Medical Condition

Examples may include:

• neurological disease
• endocrine disease
• other systemic illness

17. Other Specified / Unspecified Psychotic Disorders

Used when:

• symptoms do not fully meet criteria for a named disorder
• or information is insufficient / contradictory

18. Duration Table — Very Important for MCQs

19. One-Glance Differential Flowchart

20. Clinician-Rated Dimensional Assessment

Psychotic disorders are heterogeneous, so severity matters.

21. Cognitive Impairment in Psychosis

Many patients with psychotic disorders show deficits in:

• memory
• attention
• executive functioning
• broader cognition

This often predicts functional outcome.

Formal neuropsychological testing is useful, but brief clinical assessment can also help.

22. Cultural Considerations in Assessing Psychosis

23. Super High-Yield Exam Traps

Must Remember

• Delusions = fixed false beliefs not changed by evidence
• Auditory hallucinations are most common in schizophrenia
• Disorganized thinking is inferred from speech
• Catatonia is not specific to schizophrenia
• Negative symptoms are especially important in schizophrenia
• Delusional disorder = delusions only for ≥1 month
• Brief psychotic disorder = >1 day and <1 month
• Schizophreniform = schizophrenia picture but <6 months
• Schizophrenia = ≥6 months total, active symptoms ≥1 month
• Schizoaffective disorder = mood symptoms + psychosis, plus 2 weeks psychosis alone

24. Ultra-Fast Revision Box

25. Easy Examples for Students

26. Final Rapid Revision Sheet

Delusional Disorder

1. Core Definition

Delusional disorder = one or more delusions for at least 1 month without meeting Criterion A for schizophrenia.

2. Diagnostic Criteria Simplified

Essential Criteria

3. Delusional Disorder Flowchart

4. Most Important Exam Idea

Key distinguishing point:

Delusion is present, but schizophrenia is not.

That means:

• no full schizophrenia picture
• hallucinations may occur, but are not prominent
• behavior is usually not bizarre
• functioning is often better than schizophrenia

5. Hallucinations in Delusional Disorder

Example:

• Delusion: “My body is infested with insects”
• Possible related hallucination: crawling sensation on skin

This does not rule out delusional disorder if hallucinations are minor and theme-related.

6. Subtypes of Delusional Disorder

7. Easy Memory Trick for Subtypes

E-G-J-P-S

• Erotomanic
• Grandiose
• Jealous
• Persecutory
• Somatic

8. Subtypes in One-Line Revision Form

9. Bizarre Content Specifier

With bizarre content

Used when delusions are:

• clearly implausible
• not understandable
• not based on ordinary life experience

Example:

“Someone removed my organs and replaced them without any scars.”

10. Course Specifiers

11. Severity

Severity may be rated based on:

• delusions
• hallucinations
• disorganized speech
• abnormal psychomotor behavior
• negative symptoms

Scale:

• 0 = absent
• 4 = severe

12. Diagnostic Features

Classic Picture

13. Very Important Exclusion

Catatonia excludes delusional disorder

Why?

Because presence of catatonia + delusions suggests schizophrenia spectrum picture, so Criterion A for schizophrenia is met.

14. Associated Features

15. Insight Pattern

A classic exam phrase:

Patient may have factual insight but not true insight.

Meaning:

• may admit others see belief as irrational
• but still personally believes it completely

16. Functional Consequences

Compared with schizophrenia:

• impairment is usually more circumscribed
• appearance and behavior may look normal
• abnormality becomes clear when delusional ideas are discussed

17. Prevalence

High-yield point

• Lifetime prevalence: around 0.2%
• Most common subtype: Persecutory

Gender point

• Jealous type is probably more common in men
• overall disorder has no major sex difference

18. Development and Course

Important duration idea

• If delusions last only 1–3 months, more chance later diagnosis changes to schizophrenia
• if disorder lasts >6–12 months, diagnosis is more likely to remain delusional disorder

19. Risk Factor

Familial association:

• schizophrenia
• schizotypal personality disorder

20. Culture-Related Point

Always assess cultural and religious context before labeling belief as delusion.

21. Differential Diagnosis Table

22. Delusional Disorder vs Schizophrenia

23. Delusional Disorder vs Mood Disorder With Psychotic Features

24. Ultra-Fast Revision Box: Delusional Disorder

25. Top MCQ Traps: Delusional Disorder

• Minimum duration = 1 month
• Schizophrenia Criterion A must never be met
• Hallucinations may occur but must be not prominent
• Functioning is not markedly impaired
• Behavior is not obviously bizarre
• Catatonia rules it out
• Persecutory type is the most common
• Jealous type is more common in men
• Mood episodes can occur, but must be brief relative to delusions

Brief Psychotic Disorder

1. Core Definition

Brief psychotic disorder = sudden psychosis lasting at least 1 day but less than 1 month, followed by full return to premorbid functioning.

2. Diagnostic Criteria Simplified

Required Features

3. Required Symptom List

At least one or more of the following, and at least one must be:

1. delusions
2. hallucinations
3. disorganized speech

Fourth possible symptom:

4. grossly disorganized or catatonic behavior

4. Brief Psychotic Disorder Flowchart

5. Duration Rule

Extremely important for exams

6. Specifiers

7. Brief Reactive Psychosis

This is:

Brief psychotic disorder with marked stressor(s)

Example:

Psychosis after severe trauma, disaster, shocking loss, or major life crisis.

8. Peripartum Onset

Used when onset occurs:

• during pregnancy
• or within 4 weeks postpartum

9. Severity Rating

Can be rated on:

• delusions
• hallucinations
• disorganized speech
• abnormal psychomotor behavior
• negative symptoms

Again:

• 0 = absent
• 4 = severe

10. Diagnostic Features

Key picture

• sudden onset psychosis
• severe but short-lived
• eventual complete recovery to prior level

11. Associated Features

12. Important Functional Point

Even though the disorder is brief, impairment can be severe:

• poor judgment
• inability to care for hygiene/nutrition
• risky behavior due to psychosis

13. Prevalence

Brief psychotic disorder may account for about 2%–7% of first-onset psychosis in some countries.

14. Development and Course

15. Important Course Rule

16. Culture-Related Point

Do not diagnose brief psychotic disorder if the experience is a culturally sanctioned response.

Examples:

• hearing voices in a religious ritual
• seeing or interacting with a recently deceased loved one in a culturally normal bereavement context

17. Differential Diagnosis Table

18. Brief Psychotic Disorder vs Delusional Disorder

19. Brief Psychotic Disorder vs Schizophreniform Disorder

20. Ultra-Fast Revision Box: Brief Psychotic Disorder

21. Top MCQ Traps: Brief Psychotic Disorder

• Minimum duration = 1 day
• Maximum duration = less than 1 month
• Must return to premorbid functioning
• One symptom must be delusion, hallucination, or disorganized speech
• Can have catatonia
• Can be with marked stressor(s) = brief reactive psychosis
• Can be with peripartum onset
• Rule out mood disorder, schizophrenia, substances, and medical causes

22. Comparison Table

23. Examples

24. Final Sheet

Schizophreniform Disorder & Schizophrenia

1. Big Picture

Psychotic Disorders Duration Ladder

• Brief Psychotic Disorder = >1 day to <1 month
• Schizophreniform Disorder = 1 month to <6 months
• Schizophrenia = ≥6 months

2. Core Psychotic Symptoms

These are the same for both schizophreniform disorder and schizophrenia.

Criterion A Symptoms

Need 2 or more of the following, and at least 1 must be:

• Delusions
• Hallucinations
• Disorganized speech

Other possible symptoms:

• Grossly disorganized or catatonic behavior
• Negative symptoms

3. Schizophreniform Disorder

Definition

Same symptom pattern as schizophrenia, but duration is shorter.

Provisional Schizophreniform Disorder

Use provisional when:

• Patient has been ill less than 6 months
• Has not yet recovered
• You cannot yet know whether illness will resolve before 6 months

Still symptomatic
+
Duration not yet reached 6 months
=
Schizophreniform Disorder (Provisional)

Good Prognostic Features

Need at least 2 of these:

Specifier

• With good prognostic features = at least 2 present
• Without good prognostic features = fewer than 2

4. Schizophrenia

Definition

A chronic psychotic disorder with:

• characteristic psychotic symptoms,
• marked functional decline,
• and continuous disturbance for at least 6 months.

5. Schizophreniform vs Schizophrenia

6. Schizophrenia Criteria Simplified

Criterion B: Functional Decline

There must be marked decline in 1 or more major areas:

• Work
• Relationships
• Self-care
• Academic functioning

Criterion C: Time Requirement

Continuous signs of illness for at least 6 months, including:

• ≥1 month active symptoms
• remaining time can be prodromal or residual symptoms

Prodromal / Residual Symptoms

May include:

• odd beliefs
• unusual perceptual experiences
• vague speech
• social withdrawal
• negative symptoms

7. Negative Symptoms

Very important in exams.

Other commonly associated negative-type features

• social withdrawal
• reduced speech
• low motivation

8. Mood Symptoms: Key Distinction

Schizophrenia vs Mood Disorder With Psychosis

Schizophrenia

• Psychosis is present
• Mood episodes, if present, are for minority of total illness duration

Major depression/bipolar with psychotic features

• Psychosis occurs only during mood episodes

9. Schizoaffective Disorder vs Schizophrenia

10. Autism + Schizophrenia Rule

If there is history of autism spectrum disorder or childhood communication disorder:

You diagnose schizophrenia additionally only if:

• prominent delusions or hallucinations are present
• for at least 1 month

This is very testable.

11. Catatonia Specifier

Both disorders can be specified:

• with catatonia

Coding note:

• additional code F06.1 for catatonia associated with the disorder

12. Severity Specifier

Severity may be rated from 0 to 4 for:

• delusions
• hallucinations
• disorganized speech
• abnormal psychomotor behavior
• negative symptoms

13. Associated Features of Schizophrenia

These are common but not required criteria.

Insight Point

Lack of insight (anosognosia) is common in schizophrenia.

It predicts:

• nonadherence to treatment
• relapse
• poorer outcome

This is a strong exam point.

14. Suicide in Schizophrenia

Facts

• About 5%–6% die by suicide
• Around 20% attempt suicide
• suicidal ideation is common

15. Course and Prognosis of Schizophrenia

Course

• often gradual onset
• social withdrawal may appear early
• chronic relapsing course is common
• remission can occur
• recovery possible in some patients

Prognosis Pearls

Poorer prognosis is associated with:

• male sex
• long duration before treatment
• poor premorbid functioning
• prominent negative symptoms
• cognitive impairment

16. Risk Factors for Schizophrenia

17. Differential Diagnosis

Delusional Disorder vs Schizophrenia

In delusional disorder:

• delusions are present
• but other classic schizophrenia symptoms are absent or not prominent

Substance-Induced Psychosis

Think this when psychosis has a clear:

• onset after substance use
• improvement after stopping substance

18. Functional Consequences of Schizophrenia

Common impairments:

• academic decline
• poor employment
• social isolation
• reduced self-care
• lower occupational achievement than expected

19. Comorbidity in Schizophrenia

20. Fast Revision Box

21. Exam Traps

Trap 1

Same symptom criteria in both disorders.
Main difference = duration and functional decline.

Trap 2

Schizophreniform disorder does not require social/occupational dysfunction.

Trap 3

If illness goes beyond 6 months → change diagnosis to schizophrenia.

Trap 4

If psychosis occurs only during mood episodes → not schizophrenia.

Trap 5

If mood episodes are present for majority of illness → think schizoaffective disorder.

Trap 6

In autism/communication disorder history, schizophrenia requires prominent delusions or hallucinations for ≥1 month.

22. One-Look Table

23. Example MCQ-Style Clinical Cases

Schizoaffective Disorder

1. One-Line Definition

Schizoaffective disorder = schizophrenia symptoms + major mood episode, with at least 2 weeks of psychosis without mood symptoms, and mood episodes present for the majority of the total illness duration.

This is the core exam formula.

2. Core Diagnostic Formula

Must have all 4:

3. Diagnostic Flowchart

4. The Most Important MCQ Rule

Think of schizoaffective disorder as:

5. Criterion A Simplified

Requirement:

An uninterrupted period of illness during which there is:

• a major depressive episode or manic episode
• occurring concurrently with Criterion A of schizophrenia

Schizophrenia Criterion A Symptoms

You only need to remember that schizoaffective disorder requires Criterion A of schizophrenia, which includes psychotic symptoms like:

Important Depression Note

If the mood episode is major depressive episode, it must include:

Depressed mood

6. Criterion B = Key Distinguishing Feature

Requirement:

There must be:

Delusions or hallucinations for at least 2 weeks in the absence of a major mood episode

This is what separates schizoaffective disorder from mood disorder with psychotic features.

7. Criterion C = Another Very Important Rule

Requirement:

Mood episode symptoms must be present for the majority of total duration of the illness.

Easy memory line:

Mood symptoms = most of the illness

Not just a brief part.

Diagnostic Logic

• If mood symptoms are brief → think schizophrenia
• If mood symptoms are majority → think schizoaffective disorder

8. Criterion D

Symptoms must not be due to:

• substance use
• medication
• another medical condition

9. Bipolar Type vs Depressive Type

10. Catatonia Specifier

Can specify:

With catatonia

This is added if catatonic symptoms are present.

11. Course Specifiers

These are used only after 1 year duration of illness.

12. Severity Specifier

Severity can be rated based on psychosis symptoms in the last 7 days:

Scale:

• 0 = not present
• 4 = severe

13. Diagnostic Features: What Actually Matters

The diagnosis requires:

• an uninterrupted illness
• psychotic symptoms meeting Criterion A of schizophrenia
• a major mood episode
• 2 weeks of psychosis without mood symptoms
• mood symptoms for the majority of total illness

Very Important Clarification

For schizoaffective disorder, you do NOT need all schizophrenia criteria.

You need:

• Criterion A of schizophrenia

You do not need:

• schizophrenia social dysfunction criterion
• schizophrenia 6-month duration criterion
• autism exclusion criterion from schizophrenia diagnosis

14. High-Yield Diagnostic Distinction Table

15. Fast Differential Rule

• Psychosis only during depression/mania?
  → Mood disorder with psychotic features
• Psychosis present, mood symptoms only brief?
  → Schizophrenia
• Psychosis alone for 2 weeks + mood symptoms majority?
  → Schizoaffective disorder

16. Classic Example

17. Example That Is NOT Schizoaffective

18. Associated Features

19. Prognosis

Easy memory:

Better than schizophrenia, worse than mood disorders

20. Development and Course

Typical onset:

• usually early adulthood
• may occur from adolescence to late life

Diagnostic instability:

Diagnosis can change over time:

• schizoaffective → schizophrenia
• schizoaffective → mood disorder
• another psychotic disorder → schizoaffective

This happens because the relative amount of mood vs psychotic symptoms becomes clearer over time.

21. Bipolar Type vs Depressive Type by Age

22. Suicide Risk

Very important exam point:

Lifetime suicide risk in schizophrenia and schizoaffective disorder ≈ 5%

Risk is higher when depressive symptoms are present.

23. Risk Factors

Genetic / family risk increases if first-degree relative has:

• schizophrenia
• bipolar disorder
• schizoaffective disorder

24. Comorbidity

These contribute to reduced life expectancy.

25. There Is No Definitive Test

26. Neuropsychology / Imaging

May show:

• executive dysfunction
• verbal memory deficits
• slow processing speed
• gray matter loss

But these findings are not diagnostic.

27. Prevalence

High-yield figure:

Lifetime prevalence ≈ 0.3%

Also:

• about one-third as common as schizophrenia
• reported more commonly in women

28. Cultural Diagnostic Point

Clinicians must consider:

• cultural beliefs
• socioeconomic background
• possible diagnostic bias

Example:

Beliefs that seem delusional in one culture may be normal in another.

Also important:

African American and Hispanic individuals may be overdiagnosed with schizophrenia instead of schizoaffective disorder if mood symptoms are not adequately assessed.

29. Best Differential Diagnosis Table

30. Exam Traps

Trap 1

Psychosis must occur without mood symptoms for at least 2 weeks
If not → likely mood disorder with psychotic features

Trap 2

Mood symptoms must be present for the majority of illness
If mood symptoms are brief → likely schizophrenia

Trap 3

For the depressive form, depressed mood is required
Not just loss of interest.

Trap 4

Functional impairment is common but not required as defining criterion

Trap 5

Only Criterion A of schizophrenia is needed, not the full schizophrenia diagnosis.

31. Fast Revision Box

32. One-Glance Memory Table

33. Final MCQ Shortcut

Substance/Medication-Induced Psychotic Disorder

1. Core Definition

Prominent delusions and/or hallucinations caused by a substance, medication, or toxin.

2. Diagnostic Criteria

Essential Symptoms

At least one of the following:

• Delusions
• Hallucinations

Must Also Prove Both of These

1. Symptoms developed during or soon after:

• intoxication
• withdrawal
• medication use
• medication withdrawal

2. The substance/medication is capable of causing psychosis

Must NOT Be Better Explained By

• an independent psychotic disorder
• delirium alone

Functional Requirement

Symptoms must cause:

• distress, or
• social/occupational impairment

3. One-Line Diagnostic Formula

4. Diagnostic Flowchart

5. Key MCQ Memory Table

6. Important Exclusion Clues

Think independent psychotic disorder if:

• psychotic symptoms started before substance use
• symptoms continue for about 1 month or more after stopping substance/withdrawal
• recurrent non-substance-related psychotic episodes in the past

7. Most Important Exam Trap

Substance-induced psychotic disorder vs intoxication/withdrawal with perceptual disturbances

Substance-induced psychotic disorder

• person has delusions/hallucinations
• reality testing is impaired
• symptoms are severe enough for separate diagnosis

Intoxication/withdrawal with perceptual disturbances

• person has abnormal perceptions
• knows they are drug-induced
• reality testing remains intact

8. Differentiation Table

9. Substance Classes Commonly Causing It

During Intoxication

Common with:

• alcohol
• cannabis
• hallucinogens
• phencyclidine (PCP)
• inhalants
• sedatives/hypnotics/anxiolytics
• stimulants
• cocaine
• unknown/other substances

During Withdrawal

Common with:

• alcohol
• sedatives/hypnotics/anxiolytics
• other/unknown substances

10. Medications That May Cause Psychosis

Important examples:

• corticosteroids
• antiparkinsonian drugs
• anticonvulsants
• antihistamines
• antidepressants
• antimicrobial drugs
• cardiovascular drugs
• chemotherapeutic agents
• OTC drugs like pseudoephedrine and phenylephrine

11. Toxins That Can Cause Psychosis

Examples:

• organophosphate insecticides
• nerve gases
• carbon monoxide
• carbon dioxide
• fuels / paint / volatile substances

12. Onset Specifiers

13. Severity Specifier

Rate psychotic symptoms from 0 to 4 based on the last 7 days.

Assessed symptoms include:

• delusions
• hallucinations
• abnormal psychomotor behavior
• negative symptoms

14. Common Clinical Patterns

Alcohol-induced psychotic disorder

• usually after prolonged heavy alcohol use
• often in moderate to severe alcohol use disorder
• hallucinations are often auditory

Cocaine / amphetamine psychosis

• can begin rapidly
• often causes persecutory delusions
• may include formication = feeling bugs crawling under skin

Cannabis-induced psychotic disorder

• often after high-dose cannabis
• common features:
  • persecutory delusions
  • marked anxiety
  • emotional lability
  • depersonalization
• usually resolves within 1 day, but may last longer

15. Important Term: Formication

Sensation of insects/bugs crawling on or under the skin

Common with:

• cocaine
• amphetamine-type substances

16. Duration / Course

General Pattern

• begins during or soon after exposure/withdrawal
• may continue for days to weeks
• sometimes can persist weeks or longer

17. Prognostic / Long-Term Exam Point

A proportion later develop:

• schizophrenia spectrum disorder
• bipolar disorder

High-yield figure from the text:

• about 1/3 later receive one of these diagnoses
• highest conversion reported with cannabis-induced psychotic disorder

18. Functional Consequences

Usually:

• severely disabling
• often seen in emergency settings
• typically resolves after removal of the offending agent

19. Diagnostic Marker

If available, supportive evidence includes:

• toxic blood levels
• blood alcohol level
• measurable drug concentration

These increase diagnostic certainty.

20. Recording Rule

General Pattern

Name the diagnosis starting with the substance/medication.

Format

[severity of use disorder, if present] + [substance] use disorder
with
[substance]-induced psychotic disorder
with onset during intoxication / withdrawal / after medication use

21. Recording Examples

Example 1

A patient with severe cocaine use disorder develops delusions during intoxication:

Severe cocaine use disorder with cocaine-induced psychotic disorder, with onset during intoxication

Example 2

One-time PCP use without use disorder:

Phencyclidine-induced psychotic disorder, with onset during intoxication

22. Coding Rule You Actually Need for MCQs

The 4th-position character depends on comorbid use disorder:

24. Differential Diagnosis

25. Very Important DSM Limitation

For this diagnosis, DSM psychotic symptoms are limited to:

• delusions
• hallucinations

26. High-Yield MCQ Traps

Trap 1

Hallucinations alone can qualify
Delusions are not required.

Trap 2

If symptoms occur only in delirium, do not diagnose separately.

Trap 3

If patient knows the experience is drug-related and does not believe it is real:

• think intoxication/withdrawal with perceptual disturbances
• not psychotic disorder

Trap 4

Persistence for ~1 month after cessation suggests:

• independent psychotic disorder

Trap 5

A person can have both:

• prior primary psychotic disorder
• and a new substance-induced psychotic disorder

One does not rule out the other.

27. Revision Box

28. 10-Second Exam Summary

Psychosis + substance timing + known causative agent
- delirium
- primary psychotic disorder
= Substance/Medication-Induced Psychotic Disorder

29. Mini Clinical Examples

30. Most Testable Points

• only delusions and/or hallucinations are required
• must have clear substance/medication relationship
• must exclude delirium
• must exclude primary psychotic disorder
• psychosis can occur with intoxication, withdrawal, or medication use
• reality testing intact → perceptual disturbance, not psychotic disorder
• persistence after cessation suggests independent psychosis
• cocaine/amphetamine can cause persecutory delusions + formication
• cannabis psychosis often causes anxiety + persecutory delusions

Psychotic Disorder Due to Another Medical Condition

1. Core Definition

Prominent hallucinations or delusions caused directly by another medical condition.

2. Diagnostic Criteria

Must have:

3. Fast Diagnostic Formula

4. Diagnostic Flowchart

5. Coding / Specifier

Based on predominant symptom:

Code Specifier

• F06.2 With delusions
• F06.0 With hallucinations

Important coding rule

• Mention the medical condition name in the diagnosis.
• Code the medical condition first, then the psychotic disorder.

Example

• C34.90 malignant lung neoplasm
• F06.2 psychotic disorder due to malignant lung neoplasm, with delusions

6. Severity Specifier

Severity is rated for the past 7 days on a 0 to 4 scale.

Rate these symptom domains:

• Delusions
• Hallucinations
• Abnormal psychomotor behavior
• Negative symptoms

7. Most Important Diagnostic Feature

The psychosis must be due to the physiological effects of a medical condition, not merely a psychological reaction to illness.

Example

• If someone becomes psychotic because of the direct brain effect of lupus → this diagnosis
• If someone has a brief psychotic reaction because of the stress of severe illness → think brief psychotic disorder with marked stressor

8. Hallucinations: High-Yield Points

Hallucinations can occur in any sensory modality:

• Visual
• Auditory
• Olfactory
• Gustatory
• Tactile

9. Delusions: Common Themes

Most common:

Persecutory delusions

10. Reality Testing Rule

11. How to Decide if Medical Condition is the Cause

The “3 T/B/T” Approach

1. Biological Plausibility

Is there a medical condition capable of causing psychosis?

Examples:

• Severe infection
• Lupus
• Porphyria
• Temporal lobe epilepsy

2. Temporality

Did psychosis begin, worsen, or improve along with the medical condition?

3. Typicality

Are features atypical for primary psychosis?

Examples:

• Late age of onset
• Visual hallucinations
• Olfactory hallucinations

12. Best Clue for Diagnosis

Temporal association is the strongest clue.

Meaning:

Psychosis appears or worsens when the medical condition appears/worsens.

13. Common Medical Causes

14. Important Associated Conditions for MCQs

15. Prevalence: What to Remember

You do not need every number. Only remember the high-yield ones.

Must-know exam points:

• Lifetime prevalence roughly 0.21%–0.54%
• Higher in people older than 65 years
• In older adults with new-onset psychosis, about 60% may have a medical cause

16. Epilepsy and Psychosis

Psychosis related to epilepsy may be:

Most common:

Postictal psychosis

17. Development and Course

18. Age-Related High-Yield Points

Younger age groups

More likely causes:

• Epilepsy
• Head trauma
• Autoimmune disease
• Neoplastic disease

Older age groups

More likely causes:

• Neurodegenerative disease
• Stroke
• Anoxic injury
• Multiple medical comorbidities

19. Risk / Prognostic Factors

Most important factor affecting course:

Identification and treatment of the underlying medical condition

Poorer prognosis if:

• Prior CNS injury
• Head trauma
• Cerebrovascular disease

20. Suicide Risk

Not clearly defined overall, but may be increased in some conditions, especially:

• Epilepsy
• Multiple sclerosis

Especially if psychosis is present.

21. Functional Consequences

Functional disability is usually severe, but often improves if the medical cause is successfully treated.

22. Differential Diagnosis

Very Important MCQ Section

A. Delirium

Rule:

Do not diagnose this disorder if hallucinations/delusions occur exclusively during delirium.

B. Major or Mild Neurocognitive Disorder

A separate diagnosis can be given if psychosis is a direct physiological consequence of the disease.

Example:

• Psychotic disorder due to Lewy body disease, with delusions

C. Substance/Medication-Induced Psychotic Disorder

Think substance/medication-induced if symptoms occur:

• during intoxication
• during withdrawal
• shortly after use
• especially within 4 weeks

Examples

• LSD intoxication
• Alcohol withdrawal
• Steroid-induced psychosis

D. Primary Psychotic Disorders

Must be differentiated from:

• Schizophrenia
• Delusional disorder
• Schizoaffective disorder
• Bipolar disorder with psychotic features
• Major depressive disorder with psychotic features

23. Clues Favoring Medical Cause vs Primary Psychosis

24. Clues More Typical of Schizophrenia

25. Comorbidity

In people older than 80 years, this disorder is associated with:

• Major neurocognitive disorder
• Alzheimer disease
• Lewy body disease

26. Revision Box

27. One-Look Revision Table

28. Exam Traps

Trap 1
Psychosis during delirium only → do not diagnose this disorder

Trap 2
A severe medical illness causing stress does not automatically mean this diagnosis; it must be a direct physiological effect

Trap 3
Visual/olfactory hallucinations suggest medical cause, but are not definitive

Trap 4
Substance use may coexist — sometimes both diagnoses are given

Trap 5
Older age + first psychosis episode = look for medical cause

29. Memory Shortcut

Think: “P-MIND”

• P = Prominent delusions/hallucinations
• M = Medical condition causing it
• I = Impairment/distress present
• N = Not better explained by another mental disorder
• D = Delirium excluded

30. Example

Catatonia

1. Core Concept

Catatonia is not an independent disorder class in DSM-5-TR.

It is recognized as:

2. Basic Diagnostic Rule

Golden Rule

Catatonia = 3 or more out of 12 psychomotor features

3. Essential Feature

Catatonia is a marked psychomotor disturbance.

It may present as:

4. The 12 Catatonic Symptoms

Must memorize for MCQs

5. Memory Table

6. Simple Memory Trick

Think of catatonia as:

• Too little movement
• OR
• Too much strange movement
• OR
• Odd imitation behaviors

7. Important Clinical Pattern

Catatonia can swing between extremes:

Marked unresponsiveness
↔
Marked agitation

A patient may wax and wane between decreased and excessive motor activity.

8. Catatonia Associated With Another Mental Disorder

Use as a specifier

Used when catatonia occurs during:

• Neurodevelopmental disorders
• Psychotic disorders
• Bipolar disorders
• Depressive disorders
• Other mental disorders

Diagnostic Rule

Mental disorder present
+
3 or more catatonic symptoms
↓
Catatonia associated with another mental disorder

Coding Principle

Code the main mental disorder first, then catatonia.

Example:

• Schizoaffective disorder
• Then catatonia associated with schizoaffective disorder

9. Common Associations

10. Frequency / Exam Pearls

11. Why Catatonia Is Missed

12. Medical Risks of Severe Catatonia

Very important for exams

13. Catatonic Disorder Due to Another Medical Condition

This diagnosis is used when catatonia is caused by a medical illness.

Diagnostic Criteria Simplified

Need:

14. Medical Causes to Remember

15. Important Exclusions / Differential Diagnosis

Must rule out before diagnosing catatonia

16. Neuroleptic Malignant Syndrome vs Catatonia

Common exam trap

If patient is on antipsychotics, think of:

• Neuroleptic malignant syndrome
• Medication-induced movement disorders

17. Delirium and Catatonia

Key Point

A separate diagnosis of catatonic disorder due to another medical condition is not made if symptoms occur exclusively during delirium.

18. Unspecified Catatonia

Used when:

19. Catatonia Revision Box

20. Most Important MCQ Traps

• Catatonia is not a separate DSM class
• Diagnosis requires 3 or more symptoms
• Catatonia can occur in mood disorders, not just schizophrenia
• Agitation can be part of catatonia
• Must rule out medical causes
• Must rule out NMS
• Do not diagnose separately if it occurs only during delirium
• Severe catatonia can cause malnutrition, thromboembolism, hyperpyrexia

21. One-Line High-Yield Summary

Other Specified Schizophrenia Spectrum and Other Psychotic Disorder

High-Yield Notes

22. Core Idea

Used when psychotic symptoms are present, but full criteria for a specific schizophrenia spectrum disorder are not met.

Key point:

The clinician states the reason.

23. Examples to Memorize

24. Attenuated Psychosis Syndrome

Very testable

25. Other Specified vs Unspecified

Very important distinction

26. Unspecified Schizophrenia Spectrum and Other Psychotic Disorder

Used when:

• Psychotic symptoms predominate
• Full criteria for a specific psychotic disorder are not met
• Clinician does not specify reason
• Or there is insufficient information

Example:

• Emergency room setting
• Limited history
• Incomplete assessment

27. Final Rapid Revision Summary

28. Exam Notes

Catatonia:
3 or more of 12 signs
not a separate DSM class
seen in mood, psychotic, neurodevelopmental, medical conditions
rule out delirium + NMS

Other specified psychotic disorder:
psychotic symptoms present
criteria not fully met
reason is specified

Unspecified psychotic disorder:
psychotic symptoms present
criteria not fully met
reason not specified / insufficient data