Diagnostic criteria by symptom duration

Understanding the diagnostic criteria for various psychological and psychiatric disorders is crucial for USMLE Step 1. Here, we outline key childhood and adult disorders by the duration of symptoms required for diagnosis.

Symptom Duration and Diagnostic Criteria

Disorder Category	Disorder	Symptom Duration	Notes
Psychotic Disorders	Brief Psychotic Disorder	< 1 month	Sudden onset of psychotic symptoms
	Schizophreniform Disorder	1 – 6 months	Similar to schizophrenia, shorter duration
	Schizophrenia	> 6 months	Persistent psychotic symptoms
	Delusional Disorder	> 1 month	Non-bizarre delusions
Anxiety Disorders	Generalized Anxiety Disorder	> 6 months	Excessive worry about multiple events
	Separation Anxiety Disorder	> 4 weeks	Excessive fear of separation from attachment figures
	Panic Disorder	> 1 month	Recurrent panic attacks
	Phobias (Specific & Social)	> 6 months	Intense, irrational fear
	Selective Mutism	> 1 month	Consistent failure to speak in certain situations
Mood Disorders	Major Depressive Disorder	> 2 weeks	Depressed mood or loss of interest
	Manic Episode (Bipolar Disorder)	> 1 week	Elevated or irritable mood
	Dysthymic Disorder (Persistent Depressive Disorder)	> 2 years	Chronic low-level depression
	Cyclothymic Disorder	> 2 years	Periods of hypomanic and depressive symptoms
	Adjustment Disorder	< 6 months after stressor	Emotional or behavioral symptoms in response to a stressor
	Disruptive Mood Dysregulation Disorder	> 1 year	Severe temper outbursts
Trauma and Stressor-Related Disorders	Acute Stress Disorder	< 1 month	Stress response with anxiety
	Post-Traumatic Stress Disorder	> 1 month	Persistent re-experiencing of traumatic event
	Complicated Grief	> 6 months	Intense yearning and preoccupation
Neurodevelopmental Disorders	Attention Deficit Hyperactivity Disorder (ADHD)	> 6 months	Inattention and/or hyperactivity-impulsivity
	Specific Learning Disorder	> 6 months	Difficulty learning specific academic skills
	Oppositional Defiant Disorder	> 6 months	Angry, irritable, argumentative behavior
	Tourette Syndrome	> 1 year	Multiple motor and vocal tics
Sleep Disorders	Narcolepsy	> 3 months	Excessive daytime sleepiness, cataplexy

Symptom Duration and Diagnostic Criteria

Points to Remember

Psychotic Disorders: Differentiated by the duration and persistence of psychotic symptoms (e.g., brief psychotic episode vs. schizophrenia).
Anxiety Disorders: Anxiety must persist for defined periods to meet diagnostic criteria (e.g., generalized anxiety >6 months).
Mood Disorders: Differentiated by both symptom intensity and duration; manic and depressive episodes have specific time frames.
Neurodevelopmental Disorders: Typically require symptoms to be present for extended periods (e.g., ADHD >6 months) for diagnosis in childhood.
Trauma and Stressor-Related Disorders: Shorter duration for acute stress, longer duration for post-traumatic stress, which persists beyond one month.
Sleep Disorders: Symptoms such as excessive sleepiness in narcolepsy must persist for at least three months.

Tips for Exam Preparation

Memorize Key Timeframes: Understanding specific timeframes (e.g., 1 week for mania, 2 weeks for major depression) helps in quickly differentiating disorders.
Focus on Symptom Context: Know when certain symptoms appear (e.g., grief reactions for Complicated Grief Disorder).
Understand Disorder Groupings: Group similar disorders (e.g., mood or anxiety disorders) to help recall criteria more easily.

USMLE Step 1 Review Series

Curriculum

Diagnostic criteria by symptom duration

Symptom Duration and Diagnostic Criteria

Points to Remember

Tips for Exam Preparation

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