Taking History in Persistent Delusional Disorder

1. Identification Data

• Name, age, sex, marital status, occupation
• Religion, ethnicity, language
• Who the patient lives with
• Who accompanied the patient, and who provided the history (patients often deny illness)

The informant source matters greatly because patients with PDD frequently deny symptoms or present them in a way that sounds plausible. Corroboration from a family member or close contact is essential.

• Kaplan & Sadock's Comprehensive Textbook of Psychiatry

2. Chief Complaint

3. History of Present Illness (HPI)

a. Nature of the Delusion

• What is the content? (persecutory, jealous, somatic, erotomanic, grandiose, mixed)
• Is it non-bizarre - i.e., could this situation theoretically occur in real life (being followed, infidelity, infestation)?
• How fixed is the belief? Can the patient entertain even the possibility of being mistaken?
• Are there multiple delusions, or a single encapsulated one?

b. Onset and Duration

• When did the belief first appear? (Minimum 1 month duration required for diagnosis)
• Was the onset acute (days) or insidious (months/years)?
• What was happening in the patient's life at that time?

• Death of spouse or loved one
• Job loss or retirement
• Social isolation
• Financial hardship
• Major surgery or debilitating illness
• Sensory impairment - visual loss or hearing impairment (these are recognized precipitants, especially in older adults)
  • Kaplan and Sadock's Synopsis of Psychiatry, p. 2476

c. Course of the Delusion

• Has it worsened, remained stable, or fluctuated?
• Has there ever been a period of full remission?
• Have the delusions spread to new themes?

d. Impact on Functioning

• How has the belief affected daily life, work, relationships, social activity?
• Note: In PDD, impairment is directly tied to the delusional content itself, but overall personality and intellectual functioning remain relatively intact. This distinguishes it from schizophrenia.
• Has the patient become reclusive, locked themselves in? Do they avoid going out?
• Any legal or forensic consequences (complaints to police, lawsuits, threats)?

e. Behaviour Driven by the Delusion

• Has the patient acted on the belief? (e.g., confronting a supposed persecutor, stopping eating due to poison fears, seeking repeated medical tests for somatic fears)
• Any violence or aggression toward the supposed persecutor? (Delusional jealousy and erotomania carry significant violence risk)
• Any self-harm? (Suicide risk is elevated in untreated PDD)

f. Associated Symptoms

• Mood: Depressive symptoms are common comorbidities in PDD - screen for them
• Anxiety, agitation, irritability
• Hallucinations: Prominent auditory or visual hallucinations would suggest schizophrenia rather than PDD
• Cognitive symptoms: memory problems, confusion (which would point toward a dementia-related cause)
  • Kaplan & Sadock's Comprehensive Textbook, p. 12914

4. Past Psychiatric History

• Previous episodes of psychosis, delusions, depression, mania
• Prior hospitalizations - dates, duration, hospitals
• Previous treatments and their effects (antipsychotics, psychotherapy)
• Adherence to medications (non-adherence is a major problem in PDD because patients often do not believe they are ill)

5. Past Medical History

• Neurological disorders: head trauma, seizures, brain tumors, Parkinson disease, dementia (particularly Alzheimer's, Lewy body, vascular)
• Metabolic and endocrine disorders (thyroid disease, hepatic encephalopathy)
• Autoimmune or inflammatory conditions
• Sensory deficits: hearing loss or visual impairment
• Current medications (corticosteroids, dopaminergics, stimulants can all cause psychosis)
• Substance use: alcohol, cannabis, stimulants, hallucinogens - all can produce or sustain delusional states
  • Kaplan and Sadock's Synopsis of Psychiatry, p. 2476

6. Family History

• Mental illness in first-degree relatives, especially schizophrenia (family rates may be slightly elevated in PDD), depression, bipolar disorder
• Alzheimer disease runs in families - relevant if dementia needs ruling out
• Ethnic, cultural, and religious background (important for contextualizing belief content - what might appear delusional in one cultural context may be culturally normative in another)

7. Personal History (Anamnesis)

Childhood & Development

• Birth and developmental milestones
• School history, learning difficulties
• Childhood behavioral problems

Social and Occupational History

• Employment history, occupational functioning
• Quality of relationships - depth and stability of friendships
• Marital/relationship history - this is highly relevant in jealous-type PDD
• Living situation - isolation is both a precipitant and a consequence of PDD

Psychosexual History

• Especially relevant in jealous (Othello syndrome) and erotomanic (de Clerambault syndrome) subtypes
• Marital dynamics, fidelity, sexual functioning

Forensic History

• Legal issues arising from acting on delusions
• Litigious behavior - patients with persecutory delusions sometimes pursue repeated legal complaints

Substance Use

• Alcohol, cannabis, stimulants (detailed history)

8. Premorbid Personality

• Was the patient always suspicious, guarded, or mistrustful before the delusions appeared?
• Paranoid or schizoid personality traits are associated with vulnerability to PDD
• Note: patients typically have well-maintained social and occupational function before onset, which distinguishes the premorbid picture from schizophrenia

9. Social History

• Current living conditions, support systems
• Financial situation
• Stressors (bereavement, retirement, isolation)
• Caregiver involvement

Key Points for the Interview Itself

1. Build rapport before exploring delusional content. Patients are often suspicious of clinicians. Do not confront or challenge the delusion early.
2. Do not collude with the delusion - pretending to accept it establishes false rapport and ultimately undermines trust. "A clinician should not pretend to accept the delusion; this collusion further confounds reality and sets the stage for eventual distrust between the patient and the therapist." - Kaplan and Sadock's Synopsis, p. 2254
3. Use open-ended questions initially, then focus on specific themes.
4. Assess risk early - particularly for violence (jealous and erotomanic types) and suicide.
5. Note mental state carefully: patients with PDD are often well-groomed, cognitively intact, and appear normal in most respects. The delusional system may be the only abnormality found on examination. Their mood is congruent with the delusion - euphoric if grandiose, angry or fearful if persecutory.

Differential Diagnosis to Keep in Mind While Taking History