COMAT Psychiatry Final Exam Prep (2026-2027) Exam
Blueprint Overview (Based on NBOME COMAT
Psychiatry) 100 Questions and answers Already graded
A+
The NBOME COMAT Psychiatry exam is weighted according to the following topic categories:
Topic Category Percentage
Depressive, Bipolar, and Related Disorders 20-25%
Anxiety Disorders; Trauma and Stressor Related/Dissociative Disorders; OCD 20-25%
Neurocognitive Disorders 9-10%
Neurodevelopmental Disorders; Gender Dysphoria; Impulse Control Disorders 9-15%
Personality Disorders 5-8%
Schizophrenia Spectrum and Other Psychotic Disorders 8-10%
Substance-Related and Addictive Disorders 8-10%
Somatic Symptom Disorders; Sleep-Wake Disorders 6-10%
Feeding, Eating, and Elimination Disorders; Sexual Dysfunctions 5-6%
Section 1: Depressive, Bipolar, and Related Disorders (Questions 1-15)
,Q1. A 24-year-old woman presents with 6 weeks of depressed mood, anhedonia, poor sleep,
and decreased appetite. She denies any history of manic or hypomanic episodes. She has no
suicidal ideation. What is the most appropriate first-line treatment?
A) Haloperidol
B) Sertraline
C) Lithium
D) Diazepam
Answer: B – Sertraline
Rationale: This patient meets DSM-5-TR criteria for Major Depressive Disorder (MDD) ,
requiring at least 2 weeks of depressed mood or anhedonia plus additional symptoms (sleep,
appetite, energy changes) . First-line pharmacologic treatment for MDD is an SSRI (Selective
Serotonin Reuptake Inhibitor) such as sertraline, fluoxetine, or escitalopram due to their
favorable side effect profile and efficacy. Lithium is used for bipolar disorder, not unipolar
depression. Haloperidol is an antipsychotic not indicated as monotherapy for MDD. Diazepam is
a benzodiazepine that has no antidepressant properties and carries risk of dependence .
Q2. A 28-year-old man presents with a 4-day history of elevated mood, grandiosity, decreased
need for sleep, pressured speech, and increased goal-directed activity. He has no functional
impairment and has not required hospitalization. He reports a prior episode of depression 2
years ago that resolved with counseling. What is the most likely diagnosis?
A) Bipolar I disorder, manic episode
B) Bipolar II disorder, hypomanic episode
C) Cyclothymic disorder
D) Major depressive disorder with mixed features
Answer: B – Bipolar II disorder, hypomanic episode
Rationale: This patient meets criteria for a hypomanic episode (elevated mood, grandiosity,
decreased need for sleep, pressured speech, increased activity lasting ≥4 days) without marked
functional impairment or psychotic features . The absence of hospitalization and functional
decline distinguishes hypomania from mania. The prior depressive episode establishes Bipolar II
disorder (hypomanic episodes + major depressive episodes). Bipolar I requires at least one
manic episode (≥7 days or requiring hospitalization, with functional impairment). Cyclothymic
disorder involves numerous periods of hypomanic and depressive symptoms that do not meet
full episode criteria over ≥2 years .
,Q3. A 45-year-old woman with major depressive disorder has failed trials of two SSRIs at
adequate doses for 8 weeks each. She continues to have significant depressive symptoms. What
is the most appropriate next step?
A) Add a second SSRI
B) Switch to a different class of antidepressant (e.g., SNRI or bupropion)
C) Start lithium monotherapy
D) Recommend electroconvulsive therapy immediately
Answer: B – Switch to a different class of antidepressant (e.g., SNRI or bupropion)
Rationale: After failure of two SSRIs (or switching within class), guidelines recommend switching
to an antidepressant from a different class such as an SNRI (venlafaxine, duloxetine), bupropion
(NDRI), or mirtazapine (tetracyclic) . Augmentation strategies (adding a second agent) are also
appropriate options but switching classes is a standard next step. Adding a second SSRI is not
rational as they share the same mechanism. Lithium augmentation is an option for treatment-
resistant depression but not first-line after only two failed trials. ECT is reserved for severe,
treatment-refractory depression or when rapid response is needed (e.g., catatonia, high suicide
risk) .
Q4. A patient on fluoxetine (an SSRI) for 3 months develops hyperthermia, clonus, agitation, and
diaphoresis after starting linezolid for a skin infection. What is the most likely diagnosis?
A) Neuroleptic malignant syndrome (NMS)
B) Serotonin syndrome
C) Malignant hyperthermia
D) Anticholinergic toxicity
Answer: B – Serotonin syndrome
Rationale: This patient is experiencing serotonin syndrome, a life-threatening condition caused
by excessive serotonergic activity . The classic triad includes: 1) Neuromuscular
abnormalities (clonus, hyperreflexia, tremor), 2) Autonomic instability (hyperthermia,
diaphoresis, tachycardia), and 3) Altered mental status (agitation, confusion). Linezolid is a
weak MAOI and combined with an SSRI leads to serotonin excess. NMS typically presents with
"lead-pipe" rigidity (not clonus), bradykinesia, and elevated creatine kinase. Malignant
hyperthermia occurs with volatile anesthetics. Anticholinergic toxicity presents with "hot as a
hare, blind as a bat, dry as a bone, red as a beet, mad as a hatter" .
, Q5. A 32-year-old woman presents with alternating periods of high energy, decreased need for
sleep, and impulsive spending lasting 3-4 days, followed by weeks of low mood and fatigue. She
has never been hospitalized and functions well between episodes. Symptoms have been
present for the past 3 years. What is the most likely diagnosis?
A) Bipolar I disorder
B) Bipolar II disorder
C) Cyclothymic disorder
D) Borderline personality disorder
Answer: C – Cyclothymic disorder
Rationale: Cyclothymic disorder is characterized by numerous periods of hypomanic symptoms
and depressive symptoms that do not meet full episode criteria, persisting for ≥2 years in
adults . The patient's hypomanic episodes are brief (3-4 days, less than the 4-day requirement
for hypomania) and depressive symptoms do not meet full MDD criteria. Borderline personality
disorder features emotional instability but is driven by interpersonal triggers and fear of
abandonment, not distinct mood episodes .
Q6. A 55-year-old man with bipolar I disorder is maintained on lithium. He presents with
polyuria, polydipsia, and a serum sodium of 148 mEq/L. Urinalysis shows dilute urine with low
specific gravity. What is the most likely cause?
A) Syndrome of inappropriate antidiuretic hormone (SIADH)
B) Diabetes insipidus (nephrogenic)
C) Diabetes mellitus
D) Primary polydipsia
Answer: B – Diabetes insipidus (nephrogenic)
Rationale: Lithium commonly causes nephrogenic diabetes insipidus (NDI) by inhibiting ADH
action on the collecting duct, leading to inability to concentrate urine . Patients present with
polyuria, polydipsia, and hypernatremia due to free water loss. SIADH would cause
hyponatremia, not hypernatremia. Diabetes mellitus would show hyperglycemia and glucosuria.
Primary polydipsia typically presents with hyponatremia. Management includes lithium
discontinuation (if possible) or dose reduction, and thiazide diuretics or amiloride .
Blueprint Overview (Based on NBOME COMAT
Psychiatry) 100 Questions and answers Already graded
A+
The NBOME COMAT Psychiatry exam is weighted according to the following topic categories:
Topic Category Percentage
Depressive, Bipolar, and Related Disorders 20-25%
Anxiety Disorders; Trauma and Stressor Related/Dissociative Disorders; OCD 20-25%
Neurocognitive Disorders 9-10%
Neurodevelopmental Disorders; Gender Dysphoria; Impulse Control Disorders 9-15%
Personality Disorders 5-8%
Schizophrenia Spectrum and Other Psychotic Disorders 8-10%
Substance-Related and Addictive Disorders 8-10%
Somatic Symptom Disorders; Sleep-Wake Disorders 6-10%
Feeding, Eating, and Elimination Disorders; Sexual Dysfunctions 5-6%
Section 1: Depressive, Bipolar, and Related Disorders (Questions 1-15)
,Q1. A 24-year-old woman presents with 6 weeks of depressed mood, anhedonia, poor sleep,
and decreased appetite. She denies any history of manic or hypomanic episodes. She has no
suicidal ideation. What is the most appropriate first-line treatment?
A) Haloperidol
B) Sertraline
C) Lithium
D) Diazepam
Answer: B – Sertraline
Rationale: This patient meets DSM-5-TR criteria for Major Depressive Disorder (MDD) ,
requiring at least 2 weeks of depressed mood or anhedonia plus additional symptoms (sleep,
appetite, energy changes) . First-line pharmacologic treatment for MDD is an SSRI (Selective
Serotonin Reuptake Inhibitor) such as sertraline, fluoxetine, or escitalopram due to their
favorable side effect profile and efficacy. Lithium is used for bipolar disorder, not unipolar
depression. Haloperidol is an antipsychotic not indicated as monotherapy for MDD. Diazepam is
a benzodiazepine that has no antidepressant properties and carries risk of dependence .
Q2. A 28-year-old man presents with a 4-day history of elevated mood, grandiosity, decreased
need for sleep, pressured speech, and increased goal-directed activity. He has no functional
impairment and has not required hospitalization. He reports a prior episode of depression 2
years ago that resolved with counseling. What is the most likely diagnosis?
A) Bipolar I disorder, manic episode
B) Bipolar II disorder, hypomanic episode
C) Cyclothymic disorder
D) Major depressive disorder with mixed features
Answer: B – Bipolar II disorder, hypomanic episode
Rationale: This patient meets criteria for a hypomanic episode (elevated mood, grandiosity,
decreased need for sleep, pressured speech, increased activity lasting ≥4 days) without marked
functional impairment or psychotic features . The absence of hospitalization and functional
decline distinguishes hypomania from mania. The prior depressive episode establishes Bipolar II
disorder (hypomanic episodes + major depressive episodes). Bipolar I requires at least one
manic episode (≥7 days or requiring hospitalization, with functional impairment). Cyclothymic
disorder involves numerous periods of hypomanic and depressive symptoms that do not meet
full episode criteria over ≥2 years .
,Q3. A 45-year-old woman with major depressive disorder has failed trials of two SSRIs at
adequate doses for 8 weeks each. She continues to have significant depressive symptoms. What
is the most appropriate next step?
A) Add a second SSRI
B) Switch to a different class of antidepressant (e.g., SNRI or bupropion)
C) Start lithium monotherapy
D) Recommend electroconvulsive therapy immediately
Answer: B – Switch to a different class of antidepressant (e.g., SNRI or bupropion)
Rationale: After failure of two SSRIs (or switching within class), guidelines recommend switching
to an antidepressant from a different class such as an SNRI (venlafaxine, duloxetine), bupropion
(NDRI), or mirtazapine (tetracyclic) . Augmentation strategies (adding a second agent) are also
appropriate options but switching classes is a standard next step. Adding a second SSRI is not
rational as they share the same mechanism. Lithium augmentation is an option for treatment-
resistant depression but not first-line after only two failed trials. ECT is reserved for severe,
treatment-refractory depression or when rapid response is needed (e.g., catatonia, high suicide
risk) .
Q4. A patient on fluoxetine (an SSRI) for 3 months develops hyperthermia, clonus, agitation, and
diaphoresis after starting linezolid for a skin infection. What is the most likely diagnosis?
A) Neuroleptic malignant syndrome (NMS)
B) Serotonin syndrome
C) Malignant hyperthermia
D) Anticholinergic toxicity
Answer: B – Serotonin syndrome
Rationale: This patient is experiencing serotonin syndrome, a life-threatening condition caused
by excessive serotonergic activity . The classic triad includes: 1) Neuromuscular
abnormalities (clonus, hyperreflexia, tremor), 2) Autonomic instability (hyperthermia,
diaphoresis, tachycardia), and 3) Altered mental status (agitation, confusion). Linezolid is a
weak MAOI and combined with an SSRI leads to serotonin excess. NMS typically presents with
"lead-pipe" rigidity (not clonus), bradykinesia, and elevated creatine kinase. Malignant
hyperthermia occurs with volatile anesthetics. Anticholinergic toxicity presents with "hot as a
hare, blind as a bat, dry as a bone, red as a beet, mad as a hatter" .
, Q5. A 32-year-old woman presents with alternating periods of high energy, decreased need for
sleep, and impulsive spending lasting 3-4 days, followed by weeks of low mood and fatigue. She
has never been hospitalized and functions well between episodes. Symptoms have been
present for the past 3 years. What is the most likely diagnosis?
A) Bipolar I disorder
B) Bipolar II disorder
C) Cyclothymic disorder
D) Borderline personality disorder
Answer: C – Cyclothymic disorder
Rationale: Cyclothymic disorder is characterized by numerous periods of hypomanic symptoms
and depressive symptoms that do not meet full episode criteria, persisting for ≥2 years in
adults . The patient's hypomanic episodes are brief (3-4 days, less than the 4-day requirement
for hypomania) and depressive symptoms do not meet full MDD criteria. Borderline personality
disorder features emotional instability but is driven by interpersonal triggers and fear of
abandonment, not distinct mood episodes .
Q6. A 55-year-old man with bipolar I disorder is maintained on lithium. He presents with
polyuria, polydipsia, and a serum sodium of 148 mEq/L. Urinalysis shows dilute urine with low
specific gravity. What is the most likely cause?
A) Syndrome of inappropriate antidiuretic hormone (SIADH)
B) Diabetes insipidus (nephrogenic)
C) Diabetes mellitus
D) Primary polydipsia
Answer: B – Diabetes insipidus (nephrogenic)
Rationale: Lithium commonly causes nephrogenic diabetes insipidus (NDI) by inhibiting ADH
action on the collecting duct, leading to inability to concentrate urine . Patients present with
polyuria, polydipsia, and hypernatremia due to free water loss. SIADH would cause
hyponatremia, not hypernatremia. Diabetes mellitus would show hyperglycemia and glucosuria.
Primary polydipsia typically presents with hyponatremia. Management includes lithium
discontinuation (if possible) or dose reduction, and thiazide diuretics or amiloride .
