1. Legal Foundation of Testamentary Capacity

The cornerstone of testamentary capacity is the classic rule in:

Banks v Goodfellow (1870)

A testator must:

1. Understand the nature of making a will and its effects
2. Understand the extent of property being disposed
3. Understand and appreciate claims of potential beneficiaries
4. Be free from insane delusions influencing the will

This remains the gold standard internationally for assessment.

2. Purpose of Medical Evaluation

Medical evaluation aims to determine:

• Presence or absence of cognitive impairment (e.g., dementia)
• Presence of psychiatric illness (e.g., psychosis, depression)
• Whether mental disorder affected decision-making capacity
• Whether the testator had lucid intervals
• Whether there was undue influence or delusional thinking
• Whether capacity existed at the exact time of will execution

Importantly:

Diagnosis alone does NOT determine incapacity—functional ability does.

3. Core Components of Medical Evaluation

A. Clinical Interview

• Orientation (time, place, person)
• Memory (recent and remote)
• Understanding of assets and family
• Reasoning behind distribution choices

B. Mental Status Examination (MSE)

• Attention and concentration
• Thought content (delusions?)
• Insight and judgment
• Speech and coherence

C. Cognitive Testing

• MMSE / MoCA (screening tools)
• Executive function evaluation
• Memory recall tests

D. Functional Capacity Assessment

• Can the person explain:
  • What a will is?
  • What property they own?
  • Who may reasonably inherit?

E. Collateral Information

• Medical records
• Lawyer/attorney notes
• Witness statements
• Family history (with caution for bias)

4. Special Features in Medical Evaluation

(i) Time-specific assessment

Capacity must be judged at the time of will execution, not before or after.

(ii) Fluctuating capacity

Patients with dementia or psychosis may have:

• lucid intervals → valid wills possible

(iii) Retrospective evaluation (post-mortem cases)

Doctors rely on:

• hospital records
• psychiatric notes
• witness testimony
• “psychological autopsy”

(iv) Undue influence screening

Evaluators assess:

• dependency on caregiver
• isolation
• sudden change in beneficiaries

5. Methodological Standards (Best Practice)

A proper medical evaluation includes:

• Structured forensic interview
• Documentation of exact answers of testator
• Capacity assessment aligned with Banks v Goodfellow
• Written medico-legal report
• Clear opinion: capacity present / absent / indeterminate

6. Key Challenges in Evaluation

• Retrospective cases (no direct examination)
• Family conflict and biased witnesses
• Subtle dementia or mild cognitive impairment
• Over-reliance on diagnosis instead of function
• Delusional but partially rational patients
• Lack of standardized global testing tool

7. Important Case Laws on Testamentary Capacity (Medical-Legal Application)

1. Banks v Goodfellow (1870)

• Established foundational test for capacity
• Emphasized functional understanding over diagnosis

2. Kenward v Adams (1975)

• Introduced “golden rule”
• Doctors should examine elderly testators carefully before will execution
• Prevents disputes in vulnerable patients

3. Re Simpson (1977, England)

• Held: mild cognitive impairment does not automatically invalidate will
• Focus is on ability to understand property and beneficiaries

4. In the Estate of Fuld (1968)

• Reinforced that delusions must affect the will to invalidate it
• Mental illness alone is insufficient

5. Parker v Felgate (1883)

• Valid will if testator understood instructions when given
• Even if capacity deteriorated later before execution

6. Re T (Adult: Refusal of Treatment) (1992, persuasive authority used in capacity logic)

• Emphasized fluctuating capacity and decision-specific evaluation
• Supports modern principle of task-specific capacity

7. Estate of Simon (California, 1941 – widely cited comparative case)

• Testamentary capacity requires rational understanding of estate
• Demonstrates cross-jurisdictional acceptance of functional test

8. Role of Medical Expert in Court

The medical expert:

• Does NOT declare the will valid or invalid
• Provides opinion on:
  • cognition
  • psychiatric condition
  • functional capacity
• Helps court determine legal validity

9. Summary

Medical evaluation of testamentary capacity is a forensic, retrospective, and functional assessment based on:

• Cognitive ability
• Psychiatric status
• Understanding of property and beneficiaries
• Freedom from delusion influencing decisions

The legal benchmark remains Banks v Goodfellow, while modern practice emphasizes structured clinical assessment and documentation.