There is a common law presumption of capacity: unless proven otherwise, every adult is able and entitled to make their own decisions, even in situations of abuse. Decision-making capacity is a legal construct and not a medical or health care construct.

There is a lack of clear guidelines and law for assessing capacity. Nevertheless, as a legal practitioner you can:

• make an initial assessment of capacity, using basic questioning and observation of the client and looking for warning signs;
• if in doubt, seek a clinical consultation or formal capacity evaluation (see Expert assessment) by someone with expertise in assessing capacity, such as a psychiatrist, geriatrician or neuropsychologist (see Resources) ;
• make a final legal judgment about the client’s capacity for the particular decision or transaction (The Law Society of NSW, 2009, p. 1).

You may feel you are faced with a dilemma. On the one hand you might be exposed to liability for negligence for failing to act on instructions to, say, prepare a will or a power of attorney; on the other hand, you might be in trouble for failing to ensure that your client has the required capacity and is not unduly influenced by a beneficiary. (See Hamilton & Cockburn 2009, p. 16.)

If, taking into account the information on capacity in this section, you are still in doubt as to the capacity of a client who is asking you, for example, to draft a new will or other document, it might be best to discuss the matter with the Law Institute of Victoria Ethics Committee. (See also Resources.)

Recommended resources on capacity

The NSW Capacity Toolkit

The Law Society of NSW Guide, When a Client’s Capacity is in Doubt

The Office of the Adult Guardian, Queensland, Capacity guidelines for witnesses of enduring powers of attorney