PsychTimeDx

Educational reference for comparing the duration and timing requirements of common psychiatric diagnoses

Schizophrenia spectrum and other psychotic disorders

Schizoaffective Disorder

There is no 6-month minimum like schizophrenia. Instead, the clinician must understand the illness across time and confirm both psychosis without mood symptoms and mood symptoms during most of the illness.

Duration + longitudinal course

≥2 weeks of psychosis without a mood episode
Schizophrenia

At least 2 core symptoms are required, and at least 1 must be delusions, hallucinations, or disorganized speech.

1 wk1 mo6 mo1 yr2 yr
Continuous disturbance ≥6 months
Substance/Medication-Induced Psychotic

Persistence for a substantial period after withdrawal or intoxication may suggest an independent psychotic disorder.

Onset window

During or soon after exposure

Mood disorders

Bipolar I Disorder

A major depressive episode is not required for Bipolar I disorder.

1 wk1 mo6 mo1 yr2 yr
Mania ≥1 week, or any duration if hospitalization
Cyclothymic Disorder

Symptoms are present at least half the time, with no symptom-free interval longer than 2 months.

1 wk1 mo6 mo1 yr2 yr
≥2 years in adults; ≥1 year in youth
Major Depressive Disorder

Symptoms represent a change from prior functioning and cause clinically significant distress or impairment.

1 wk1 mo6 mo1 yr2 yr
≥2 weeks
Persistent Depressive Disorder

During the required period, symptom-free intervals last no longer than 2 months.

1 wk1 mo6 mo1 yr2 yr
≥2 years in adults; ≥1 year in youth
Premenstrual Dysphoric Disorder (PMDD)

The pattern should occur in most cycles during the preceding year and is confirmed prospectively with daily ratings during at least 2 symptomatic cycles.

Frequency + duration

Most cycles in the preceding year
Seasonal Pattern (Seasonal Affective)

During the last 2 years, 2 seasonal episodes must occur without nonseasonal episodes; across the lifetime, seasonal episodes substantially outnumber nonseasonal episodes.

Longitudinal course

Pattern demonstrated over ≥2 years

Anxiety disorders

Generalized Anxiety Disorder

Adults also require at least 3 associated symptoms; children require at least 1.

1 wk1 mo6 mo1 yr2 yr
More days than not for ≥6 months
Panic Disorder

The panic attacks themselves peak within minutes; the 1-month rule applies to the subsequent concern or behavior change.

1 wk1 mo6 mo1 yr2 yr
≥1 month after recurrent unexpected attacks
Selective Mutism

The disturbance lasts at least 1 month, but the first month of school is excluded.

1 wk1 mo6 mo1 yr2 yr
≥1 month, excluding the first school month
Separation Anxiety Disorder

The disturbance lasts at least 4 weeks in children and adolescents and is typically 6 months or more in adults.

No fixed minimum

≥4 weeks in youth; typically ≥6 months in adults

Obsessive-compulsive and related disorders

Obsessive-Compulsive Disorder

The 1-hour example describes daily burden, not a required duration of illness.

No fixed minimum

No minimum calendar duration

Trauma- and stressor-related disorders

Adjustment Disorder

After the stressor or its consequences end, symptoms should not persist for more than an additional 6 months.

Onset window

Begins within 3 months of the stressor
PTSD

Symptoms lasting 3 days to 1 month may fit acute stress disorder when its other criteria are met.

1 wk1 mo6 mo1 yr2 yr
More than 1 month

Somatic symptom and related disorders

Illness Anxiety Disorder

Somatic symptoms are absent or mild; health anxiety and checking or avoidance are prominent.

1 wk1 mo6 mo1 yr2 yr
≥6 months
Somatic Symptom Disorder

At least 1 distressing somatic symptom is accompanied by excessive thoughts, anxiety, or time and energy devoted to the symptom or health concern.

1 wk1 mo6 mo1 yr2 yr
Persistent state—typically >6 months

Substance-related disorders

Alcohol Use Disorder

Severity is based on the number of manifestations: mild (2–3), moderate (4–5), and severe (6 or more). Remission uses separate time windows and allows craving to remain present.

Assessment window

Within a 12-month period

Neurodevelopmental disorders

ADHD

Several symptoms must be present before age 12, occur in at least 2 settings, and interfere with functioning. The threshold is 6 symptoms per domain through age 16 and 5 at age 17 or older.

Frequency + duration

Symptoms persist ≥6 months
Autism Spectrum Disorder

Symptoms may not become fully apparent until social demands exceed capacity and must cause clinically significant impairment.

Longitudinal course

Present in the early developmental period
Tourette’s Disorder

Tics may wax and wane; onset must occur before age 18.

1 wk1 mo6 mo1 yr2 yr
>1 year since first tic onset

Neurocognitive disorders

Delirium

Evidence must support a direct physiological cause such as a medical condition, substance, withdrawal, toxin, or multiple etiologies.

Onset window

Develops over hours to days; fluctuates
Frontotemporal Neurocognitive Disorder

Relative sparing of learning, memory, and perceptual-motor function may support the behavioral variant.

Longitudinal course

Insidious onset and gradual progression
Mild Neurocognitive Disorder

Concern and preferably standardized testing support decline; delirium and other mental disorders must not better explain it.

Longitudinal course

No fixed minimum duration

Personality disorders

Antisocial Personality Disorder

The individual must be at least 18 and have evidence of conduct disorder before age 15.

Longitudinal course

Conduct pattern since age 15; diagnosis at ≥18

Disruptive and impulse-control disorders

Conduct Disorder

At least 1 qualifying behavior must have occurred during the past 6 months.

Assessment window

3 behaviors in 12 months; ≥1 in past 6 months
Oppositional Defiant Disorder (ODD)

For children under 5, behavior occurs on most days; at age 5 or older, at least weekly, unless severity/context indicates otherwise.

Frequency + duration

≥6 months

Sleep–wake disorders

Narcolepsy

At least 1 objective/supporting feature is also required: cataplexy, hypocretin deficiency, or characteristic REM findings on sleep testing.

Frequency + duration

≥3 times/week for 3 months
Nightmare Disorder

Course specifiers: acute ≤1 month; subacute >1 but <6 months; persistent ≥6 months. Severity is based on episode frequency.

No fixed minimum

No minimum duration

Feeding and eating disorders

Anorexia Nervosa

The 3-month interval defines restricting versus binge-eating/purging subtype, not minimum illness duration.

No fixed minimum

No minimum duration
Binge Eating Disorder

Regular compensatory behavior is absent and episodes do not occur exclusively during bulimia or anorexia nervosa.

Frequency + duration

≥1 episode/week for 3 months
Bulimia Nervosa

Self-evaluation is unduly influenced by weight/shape, and the disturbance does not occur exclusively during anorexia nervosa.

Frequency + duration

≥1 episode/week for 3 months