Diagnostic criteria and subtypes US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Diagnostic criteria and subtypes. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Diagnostic criteria and subtypes US Medical PG Question 1: A 29-year-old woman is brought to the physician by her father because of a change in her behavior over the past 8 months. The father says that his daughter has become increasingly withdrawn; she has not answered any phone calls or visited her family and friends. The patient says that she has to stay at home because a foreign intelligence service is monitoring her. She thinks that they are using a magnetic field to read her mind. Mental status exam shows disjointed and perseverative thinking. She is anxious and has a flat affect. Which of the following is the most likely diagnosis?
- A. Delusional disorder
- B. Schizophrenia (Correct Answer)
- C. Paranoid personality disorder
- D. Schizophreniform disorder
- E. Schizoid personality disorder
Diagnostic criteria and subtypes Explanation: ***Schizophrenia***
- The patient's presentation with **delusions of persecution and thought broadcasting**, accompanied by **disjointed, perseverative thinking**, and **flat affect** for 8 months, is highly indicative of schizophrenia.
- Schizophrenia is characterized by a combination of positive symptoms (delusions, hallucinations, disorganized speech), negative symptoms (flat affect, social withdrawal), and cognitive symptoms (disorganized thinking) lasting for at least 6 months.
*Delusional disorder*
- Delusional disorder is characterized by the presence of **non-bizarre delusions for at least 1 month** without other significant psychotic symptoms or marked impairment in functioning.
- The patient's symptoms include **disorganized thinking and flat affect**, which are not typical of delusional disorder and suggest a broader psychotic illness.
*Paranoid personality disorder*
- Characterized by a pervasive distrust and suspicion of others, where their motives are interpreted as malevolent, but **without the presence of frank delusions or other psychotic symptoms**.
- The patient is experiencing **fixed, false beliefs (delusions)** involving mind reading and foreign intelligence, which goes beyond the pervasive distrust seen in paranoid personality disorder.
*Schizophreniform disorder*
- Schizophreniform disorder presents with symptoms identical to schizophrenia, but the **duration is between 1 and 6 months**.
- Since the patient's symptoms have been present for **8 months**, it exceeds the diagnostic criteria for schizophreniform disorder, making schizophrenia a more likely diagnosis.
*Schizoid personality disorder*
- Characterized by a pervasive pattern of **detachment from social relationships** and a restricted range of expression of emotions in interpersonal settings.
- While the patient exhibits social withdrawal, this condition does **not involve delusions, disorganized thinking, or other psychotic features**.
Diagnostic criteria and subtypes US Medical PG Question 2: A 26-year-old man is brought to the emergency department by his wife because of bizarre and agitated behavior for the last 6 weeks. He thinks that the NSA is spying on him and controlling his mind. His wife reports that the patient has become withdrawn and at times depressed for the past 3 months. He lost his job because he stopped going to work 4 weeks ago. Since then, he has been working on an invention that will block people from being able to control his mind. Physical and neurologic examinations show no abnormalities. On mental status examination, he is confused and suspicious with marked psychomotor agitation. His speech is disorganized and his affect is labile. Which of the following is the most likely diagnosis?
- A. Brief psychotic disorder
- B. Schizophreniform disorder (Correct Answer)
- C. Schizotypal personality disorder
- D. Schizophrenia
- E. Delusional disorder
Diagnostic criteria and subtypes Explanation: ***Schizophreniform disorder***
- The patient's symptoms, including **delusions** (fixed false beliefs that the NSA is spying and controlling his mind), **disorganized speech**, and **agitated behavior**, are consistent with a psychotic disorder.
- The duration of active psychotic symptoms (6 weeks), which is more than 1 month but less than 6 months, fits the diagnostic criteria for **schizophreniform disorder**.
- The prodromal phase (withdrawn and depressed for 3 months) plus the active phase does not yet meet the 6-month requirement for schizophrenia.
*Brief psychotic disorder*
- This disorder is characterized by a sudden onset of psychotic symptoms lasting less than 1 month, followed by a full return to premorbid functioning.
- The patient's active psychotic symptoms have persisted for 6 weeks, exceeding the maximum duration for brief psychotic disorder.
*Schizotypal personality disorder*
- This disorder primarily involves a pervasive pattern of social and interpersonal deficits marked by acute discomfort with close relationships, as well as cognitive or perceptual distortions and eccentricities.
- While there might be odd beliefs or magical thinking, it does not typically involve the persistent and severe delusions and disorganized speech seen in this case.
- This is a personality disorder, not a psychotic disorder.
*Schizophrenia*
- Schizophrenia requires continuous signs of disturbance for at least 6 months, which includes at least 1 month of active-phase symptoms (delusions, hallucinations, disorganized speech).
- The patient's total duration of illness (3 months of prodromal symptoms plus 6 weeks of active symptoms) totals approximately 4.5 months, which is less than the 6-month minimum duration required for a diagnosis of schizophrenia.
*Delusional disorder*
- The primary feature of delusional disorder is the presence of one or more delusions for at least 1 month, without other prominent psychotic symptoms such as disorganized speech or behavior.
- This patient exhibits prominent **disorganized speech**, **labile affect**, and **disorganized behavior** (bizarre invention work), which are not characteristic of delusional disorder.
- Functioning is more impaired than typically seen in delusional disorder.
Diagnostic criteria and subtypes US Medical PG Question 3: A 25-year-old man presents to his primary care physician with a chief complaint of "failing health." He states that he typically can converse with animals via telepathy, but is having trouble right now due to the weather. He has begun taking an assortment of Peruvian herbs to little avail. Otherwise he is not currently taking any medications. The patient lives alone and works in a health food store. He states that his symptoms have persisted for the past eight months. On physical exam, you note a healthy young man who is dressed in an all burlap ensemble. When you are obtaining the patient's medical history there are several times he is attempting to telepathically connect with the animals in the vicinity. Which of the following is the most likely diagnosis?
- A. Brief psychotic disorder
- B. Schizoid personality disorder
- C. Schizophrenia
- D. Schizophreniform disorder
- E. Schizotypal personality disorder (Correct Answer)
Diagnostic criteria and subtypes Explanation: ***Schizotypal personality disorder***
- This patient exhibits **eccentric behavior**, **magical thinking** (telepathy with animals), and **odd perceptions** that are characteristic of schizotypal personality disorder.
- The duration of symptoms (eight months) is consistent with a personality disorder, as these patterns are pervasive and long-standing.
*Brief psychotic disorder*
- Symptoms of brief psychotic disorder must last for **at least one day but less than one month**, with eventual full return to premorbid functioning.
- This patient's symptoms have persisted for eight months, making this diagnosis unlikely.
*Schizoid personality disorder*
- Characterized by **detachment from social relationships** and a restricted range of emotional expression, with no interest in social interactions.
- While this patient lives alone, his primary symptoms are **peculiar thoughts and behaviors**, not primarily a lack of social interest or flattened affect.
*Schizophrenia*
- Requires continuous signs of disturbance for **at least six months**, including at least one month of **active-phase symptoms** (delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, negative symptoms).
- While this patient has some peculiar symptoms, they do not meet the full criteria for schizophrenia, lacking clear-cut delusions or hallucinations and having a more pervasive pattern of oddness.
*Schizophreniform disorder*
- Involves symptoms similar to schizophrenia but with a duration of **at least one month but less than six months**.
- This patient's symptoms have lasted eight months, exceeding the maximum duration for schizophreniform disorder.
Diagnostic criteria and subtypes US Medical PG Question 4: A 24-year-old man is brought to your emergency department under arrest by the local police. The patient was found naked at a busy intersection jumping up and down on top of a car. Interviewing the patient, you discover that he has not slept in 2 days because he does not feel tired. He reports hearing voices. The patient was previously hospitalized 1 year ago with auditory hallucinations, paranoia, and a normal mood. What is the most likely diagnosis?
- A. Schizophrenia
- B. Bipolar disorder
- C. Brief psychotic disorder
- D. Schizotypal disorder
- E. Schizoaffective disorder (Correct Answer)
Diagnostic criteria and subtypes Explanation: ***Schizoaffective disorder***
- This patient demonstrates the **hallmark feature** of schizoaffective disorder: **psychotic symptoms occurring both during AND independent of mood episodes**.
- **Current presentation**: Clear **manic episode** (decreased need for sleep, grandiose/disinhibited behavior, psychomotor agitation) with psychotic features (auditory hallucinations).
- **Previous hospitalization**: **Psychotic symptoms (hallucinations, paranoia) in the absence of a mood episode** ("normal mood"), requiring hospitalization for at least 2 weeks - this is the **key diagnostic criterion** for schizoaffective disorder.
- The diagnosis requires an **uninterrupted period of illness** with both psychotic symptoms (meeting Criterion A for schizophrenia) and a major mood episode, PLUS psychotic symptoms for **≥2 weeks without prominent mood symptoms**.
*Bipolar disorder*
- In bipolar disorder with psychotic features, psychotic symptoms occur **exclusively during mood episodes** (manic, hypomanic, or depressive).
- This patient's previous hospitalization with psychosis but **"normal mood"** indicates psychotic symptoms independent of mood episodes, which **rules out** bipolar disorder and points to schizoaffective disorder.
- While the current presentation shows mania with psychosis, the longitudinal course is critical for diagnosis.
*Schizophrenia*
- Schizophrenia involves **continuous psychotic symptoms** without prominent mood episodes dominating the clinical picture.
- This patient has **prominent manic symptoms** (decreased sleep, grandiose behavior, agitation) that are central to the current presentation, making schizophrenia less likely.
- The presence of full mood episodes that occupy a **substantial portion** of the illness duration favors schizoaffective disorder over schizophrenia.
*Brief psychotic disorder*
- Brief psychotic disorder involves psychotic symptoms lasting **<1 month** with full return to baseline functioning.
- This patient has a **recurrent course** with hospitalization 1 year ago, indicating a chronic/recurring condition rather than a brief, self-limited episode.
*Schizotypal disorder*
- This is a **personality disorder** characterized by social deficits, cognitive/perceptual distortions, and eccentric behavior, but **NOT overt psychotic episodes**.
- Does not involve acute psychotic breaks with severe symptoms like hallucinations requiring hospitalization or manic episodes.
Diagnostic criteria and subtypes US Medical PG Question 5: A 20-year-old male is involuntarily admitted to the county psychiatric unit for psychotic behavior over the past three months. The patient's mother explained to the psychiatrist that her son had withdrawn from family and friends, appeared to have no emotions, and had delusions that he was working for the CIA. When he spoke, his sentences did not always seem to have any connection with each other. The mother finally decided to admit her son after he began stating that he "revealed too much information to her and was going to be eliminated by the CIA." Which of the following diagnoses best fits this patient's presentation?
- A. Schizophrenia
- B. Brief psychotic disorder
- C. Schizophreniform disorder (Correct Answer)
- D. Schizoid personality disorder
- E. Schizotypal personality disorder
Diagnostic criteria and subtypes Explanation: ***Schizophreniform disorder***
- The patient exhibits classic symptoms of **psychosis**, including delusions, disorganized speech, flat affect, and social withdrawal, which are characteristic of schizophrenia spectrum disorders.
- The duration of symptoms (3 months) fits the criteria for **schizophreniform disorder**, which is when psychotic symptoms last between 1 month and 6 months.
*Schizophrenia*
- Schizophrenia requires symptoms to be present for at least **6 months**, including at least 1 month of active-phase symptoms.
- While this patient's symptoms are consistent with psychotic disorder, the **duration criteria** for schizophrenia have not yet been met.
*Brief psychotic disorder*
- Brief psychotic disorder is characterized by symptoms lasting from **1 day to 1 month**, with eventual full return to premorbid functioning.
- The patient's symptoms have persisted for **3 months**, exceeding the maximum duration for brief psychotic disorder.
*Schizoid personality disorder*
- This disorder is characterized by a pervasive pattern of **detachment from social relationships** and a restricted range of emotional expression.
- While the patient exhibits social withdrawal, the presence of **delusions, disorganized speech, and flat affect** indicates a psychotic disorder, not merely a personality disorder.
*Schizotypal personality disorder*
- Schizotypal personality disorder involves pervasive social and interpersonal deficits with **cognitive or perceptual distortions** and eccentric behaviors.
- While it can involve odd beliefs, it does not typically include the prominent, fixed, and systematized **delusions and disorganized speech** seen in this patient's presentation.
Diagnostic criteria and subtypes US Medical PG Question 6: A 21-year-old man presents to the emergency room requesting surgery to remove "microchips," which he believes were implanted in his brain by "Russian spies" 6 months ago to control his thoughts. He also reports hearing the "spies" talk to each other through embedded "microspeakers." You notice that his hair appears unwashed and some of his clothes are on backward. Urine toxicology is negative for illicit drugs. Which of the following additional findings are you most likely to see in this patient during the course of his illness?
- A. Anhedonia, guilty rumination, and insomnia
- B. Grandiose delusions, racing thoughts, and pressured speech
- C. Asociality, flat affect, and alogia (Correct Answer)
- D. Amnesia, multiple personality states, and de-realization
- E. Intrusive thoughts, ritualized behaviors, and anxious mood
Diagnostic criteria and subtypes Explanation: ***Asociality, flat affect, and alogia***
- This patient exhibits **delusions (persecutory, control)** and **auditory hallucinations**, classic positive symptoms of **schizophrenia**. The question asks about findings "during the course of his illness," which points to the **typical progression of schizophrenia**: patients initially present with **positive symptoms** (as seen in this case) and **over time develop negative symptoms** such as **asociality** (lack of motivation to engage in social interaction), **flat affect** (reduced emotional expression), and **alogia** (poverty of speech).
- The disorganized appearance (unwashed hair, clothes on backward) already demonstrates **disorganized behavior**, part of the schizophrenia spectrum. Negative symptoms typically emerge or worsen as the illness progresses, representing the most likely additional findings.
*Anhedonia, guilty rumination, and insomnia*
- While **anhedonia** and **insomnia** can be seen in schizophrenia, their presence alongside prominent **guilty rumination** would more strongly suggest a **depressive disorder with psychotic features**, rather than primary schizophrenia, especially with the patient's specific, classic psychotic symptoms.
- The primary symptoms described (delusions of control, auditory hallucinations) are more characteristic of primary psychotic disorders, and guilty rumination is not a typical feature of schizophrenia progression.
*Grandiose delusions, racing thoughts, and pressured speech*
- These symptoms are hallmark features of **mania** or a **manic episode with psychotic features**. While psychotic features can occur in bipolar disorder with mania, the patient's specific delusions of being controlled by spies and hearing voices discussing him are more typical of schizophrenia.
- The absence of information about elevated mood, increased energy, or decreased need for sleep also makes mania less likely compared to schizophrenia.
*Amnesia, multiple personality states, and de-realization*
- These symptoms are characteristic of **dissociative disorders**. **Amnesia** and **multiple personality states** (now known as identity alteration in dissociative identity disorder) involve disturbances in memory and identity.
- **De-realization** involves feelings of unreality regarding one's surroundings. None of these align with the patient's primary presentation of well-formed delusions and hallucinations characteristic of a psychotic disorder.
*Intrusive thoughts, ritualized behaviors, and anxious mood*
- These are core features of **obsessive-compulsive disorder (OCD)**. The patient's symptoms are clearly defined as delusions (fixed false beliefs) and hallucinations (perceptions without external stimuli), which are distinct from the ego-dystonic intrusive thoughts and ritualistic compulsions of OCD.
- While anxiety may be present in psychotic disorders, the primary presentation here is not dominated by OCD-like symptoms, and these would not be expected to develop as part of schizophrenia's natural course.
Diagnostic criteria and subtypes US Medical PG Question 7: A 27-year-old woman is brought to the office at the insistence of her fiancé to be evaluated for auditory hallucinations for the past 8 months. The patient’s fiancé tells the physician that the patient often mentions that she can hear her own thoughts speaking aloud to her. The hallucinations have occurred intermittently for at least 1-month periods. Past medical history is significant for hypertension. Her medications include lisinopril and a daily multivitamin both of which she frequently neglects. She lost her security job 7 months ago after failing to report to work on time. The patient’s vital signs include: blood pressure 132/82 mm Hg; pulse 72/min; respiratory rate 18/min, and temperature 36.7°C (98.1°F). On physical examination, the patient has a flat affect and her focus fluctuates from the window to the door. She is disheveled with a foul smell. She has difficulty focusing on the discussion and does not quite understand what is happening around her. A urine toxicology screen is negative. Which of the following is the correct diagnosis for this patient?
- A. Schizoaffective disorder
- B. Schizophrenia (Correct Answer)
- C. Schizoid personality disorder
- D. Schizophreniform disorder
- E. Schizotypal personality disorder
Diagnostic criteria and subtypes Explanation: ***Schizophrenia***
- The patient exhibits core symptoms of schizophrenia, including **auditory hallucinations** (hearing thoughts speaking aloud), **disorganized thinking** (difficulty focusing, fluctuating focus), and **negative symptoms** (flat affect, disheveled, foul smell, loss of job due to poor function). These symptoms have been present for **at least 6 months** (8 months of hallucinations, 7 months of job loss), which meets the diagnostic criteria.
- The duration of symptoms (over 6 months) differentiates it from schizophreniform disorder, and the absence of prominent mood episodes rules out schizoaffective disorder.
*Schizoaffective disorder*
- This diagnosis requires a **major mood episode** (depressive or manic) concurrent with Criterion A of schizophrenia, along with a period of **at least 2 weeks of delusions or hallucinations in the absence of prominent mood symptoms**.
- While the patient has some signs of distress (lost job, disorganized), a full major mood episode is not described, and the primary symptoms are clearly psychotic.
*Schizoid personality disorder*
- This is characterized by a pervasive pattern of **detachment from social relationships** and a restricted range of emotional expression, often appearing indifferent to praise or criticism.
- The patient's symptoms are primarily psychotic (hallucinations, disorganized thought), not just social withdrawal or emotional flatness. She doesn't necessarily avoid social contact, but her psychosis interferes with it.
*Schizophreniform disorder*
- This disorder presents with symptoms identical to schizophrenia but with a **duration of at least 1 month but less than 6 months**.
- The patient's symptoms, particularly the auditory hallucinations, have been present for 8 months and are therefore outside the timeframe for schizophreniform disorder.
*Schizotypal personality disorder*
- This disorder involves a pervasive pattern of **social and interpersonal deficits** marked by acute discomfort with, and reduced capacity for, close relationships, as well as **cognitive or perceptual distortions** and eccentric behaviors.
- While there may be some odd beliefs or magical thinking, **full-blown psychotic symptoms like prominent auditory hallucinations** (hearing thoughts speaking aloud) are generally not present as consistently or severely as seen in this patient, who meets criteria for a major psychotic disorder.
Diagnostic criteria and subtypes US Medical PG Question 8: Two days after undergoing hemicolectomy for colon cancer, a 78-year-old man is found agitated and confused in his room. He says that a burglar broke in. The patient points at one corner of the room and says “There he is, doctor!” Closer inspection reveals that the patient is pointing to his bathrobe, which is hanging on the wall. The patient has type 2 diabetes mellitus and arterial hypertension. Current medications include insulin and hydrochlorothiazide. His temperature is 36.9°C (98.4°F), pulse is 89/min, respirations are 15/min, and blood pressure is 145/98 mm Hg. Physical examination shows a nontender, nonerythematous midline abdominal wound. On mental status examination, the patient is agitated and oriented only to person. Which of the following best describes this patient's perception?
- A. Hallucination
- B. Illusion (Correct Answer)
- C. Loose association
- D. Delusion
- E. External attribution
Diagnostic criteria and subtypes Explanation: ***Illusion***
- An **illusion** is a **misinterpretation of an actual external stimulus**, as seen when the patient perceives his bathrobe as a burglar.
- This symptom, combined with **agitation**, **confusion**, and **recent surgery**, is highly suggestive of **delirium**.
*Hallucination*
- A **hallucination** is a **perception in the absence of an external stimulus**, meaning the patient would see or hear something that is not there at all.
- The patient here is clearly reacting to an existing object (the bathrobe), albeit misinterpreting it.
*Loose association*
- **Loose association** refers to a **thought disorder** where ideas shift from one subject to another in a way that is unrelated or minimally related, making the speech difficult to follow.
- This describes a pattern of thought, not a perceptual disturbance involving an external object.
*Delusion*
- A **delusion** is a **fixed, false belief** that is not amenable to change in light of conflicting evidence and is not in keeping with the individual's cultural background.
- While the patient believes a burglar is present, this belief arises from a direct misinterpretation of an object rather than a fixed, unfounded belief.
*External attribution*
- **External attribution** is a psychological concept where individuals ascribe responsibility for events or outcomes to **external factors** rather than internal ones.
- This term describes a cognitive bias in explaining causality, not a perceptual disturbance.
Diagnostic criteria and subtypes US Medical PG Question 9: A 23-year-old woman is brought to the physician by her father because of strange behavior for the past 6 months. The father reports that his daughter has increasingly isolated herself in college and received poor grades. She has told her father that aliens are trying to infiltrate her mind and that she has to continuously listen to the radio to monitor these activities. She appears anxious. Her vital signs are within normal limits. Physical examination shows no abnormalities. Neurologic examination shows no focal findings. Mental status examination shows psychomotor agitation. She says: “I can describe how the aliens chase me except for my car which is parked in the garage. You know, the sky is beautiful today. Why does my mother have a cat?” Which of the following best describes this patient's thought process?
- A. Circumstantial speech
- B. Clang associations
- C. Flight of ideas
- D. Thought-blocking
- E. Loose associations (Correct Answer)
Diagnostic criteria and subtypes Explanation: ***Loose associations***
- This is characterized by a **lack of logical connection** between thoughts or ideas, leading to a disorganized and incoherent flow of speech. The patient's statements about aliens, her car, the sky, and her mother's cat are **unrelated and lack a clear thematic thread**.
- It is a key feature of **thought disorganization** and is commonly seen in psychotic disorders like **schizophrenia**.
*Circumstantial speech*
- This involves including a **multitude of unnecessary details** before finally arriving at the point or answering the question.
- While the patient's speech is disorganized, it does not demonstrate the characteristic meandering yet goal-directed nature of circumstantiality.
*Clang associations*
- This refers to the **association of words based on their sound** rather than their meaning, often involving rhyming or alliteration.
- The patient's statements do not exhibit a pattern of rhyming or sound-based word choices.
*Flight of ideas*
- This is a rapid, continuous progression from one thought to another, with thoughts often **connected by tangential associations** but still having some discernable link.
- Although the patient's thoughts shift rapidly, the connections are not simply tangential; they are largely absent, suggesting a more severe form of disorganization than flight of ideas typically entails.
*Thought-blocking*
- This is an **abrupt cessation of thought or speech** in the middle of a sentence, often followed by a new and unrelated thought.
- The patient's speech flows continuously, albeit incoherently, without sudden stops or breaks.
Diagnostic criteria and subtypes US Medical PG Question 10: A 25-year-old woman is brought to a psychiatrist's office by her husband who states that he is worried about her recent behavior, as it has become more violent. The patient's husband states that his family drove across the country to visit them and that his wife 'threatened his parents with a knife' at dinner last night. Police had to be called to calm her down. He states that she has been acting 'really crazy' for the last 9 months, and the initial behavior that caused him alarm was her admission that his deceased sister was talking to her through a decorative piece of ceramic art in the living room. Initially, he thought she was joking, but soon realized her complaints of 'hearing ghosts' talking to her throughout the house were persisting and 'getting worse'. Over the past 9 months, she has experienced multiple periods of profound sadness, with persistent insomnia and an unintentional weight loss of 12 pounds over several months. She has been complaining of feeling 'worthless' and has had markedly diminished interest in activities for much of this time period. Her general hygiene has also suffered from her recent lack of motivation and she insists that the 'ghosts' are asking her to kill as many people as she can so they won't be alone in the house. Her husband is extremely concerned that she may harm herself or someone else. He states that she currently does not take any medications or illicit drugs as far as he knows. She does not smoke or drink alcohol. The patient herself does not make eye contact or want to speak to the psychiatrist, allowing her husband to speak on her behalf. Which of the following is the most likely diagnosis in this patient?
- A. Schizophreniform disorder
- B. Schizophrenia
- C. Delusional disorder
- D. Schizoaffective disorder (Correct Answer)
- E. Brief psychotic disorder
Diagnostic criteria and subtypes Explanation: ***Schizoaffective disorder***
- This patient exhibits symptoms of both a **major depressive disorder** (multiple periods of profound **sadness**, persistent **insomnia**, **weight loss** over several months, feelings of **worthlessness**, and markedly **diminished interest in activities**) and a **psychotic disorder** (auditory **hallucinations**, command hallucinations, **delusions**, violent behavior).
- The total symptom duration is **9 months**, with **mood symptoms present for the majority of this period**, meeting the key DSM-5 criterion for schizoaffective disorder.
- The patient also demonstrates **psychotic symptoms (hallucinations) that persist throughout**, including periods when mood symptoms may fluctuate, satisfying the requirement for delusions or hallucinations for ≥2 weeks in the absence of a major mood episode.
- The combination of prominent mood episodes concurrent with schizophrenia-spectrum symptoms, with mood symptoms present for the majority of the illness duration, confirms schizoaffective disorder.
*Schizophreniform disorder*
- This disorder involves symptoms characteristic of **schizophrenia** lasting **between 1 and 6 months**.
- The patient's symptoms have been present for **9 months**, exceeding the maximum duration for schizophreniform disorder.
*Schizophrenia*
- Schizophrenia requires persistent psychotic symptoms lasting **at least 6 months**, with at least one month of active-phase symptoms.
- While this patient has psychotic symptoms for 9 months, the **prominent and prolonged depressive symptoms** that are present for the **majority of the illness duration** distinguish this from schizophrenia.
- In schizophrenia, mood symptoms, if present, are **brief relative to the total duration** of the psychotic illness, which is not the case here.
*Delusional disorder*
- Delusional disorder is characterized by **non-bizarre delusions** for at least 1 month, without other prominent psychotic symptoms.
- This patient experiences prominent **auditory hallucinations** ("hearing ghosts," "deceased sister talking to her") and **command hallucinations**, which are not features of delusional disorder.
- The presence of hallucinations rules out this diagnosis.
*Brief psychotic disorder*
- This diagnosis involves sudden onset of psychotic symptoms lasting **more than 1 day but less than 1 month**, with eventual full recovery.
- The patient's symptoms have persisted for **9 months**, far exceeding the duration criterion for brief psychotic disorder.
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