Introduction:
In the realm of contracts, gifts, and transactions, the issue of capacity holds significant importance. There are circumstances where one party lacks the mental capacity to fully understand the nature and consequences of their actions. In such cases, the law provides avenues to set aside these agreements. Let's explore some scenarios where lack of capacity can lead to the invalidation of contracts and gifts.

  1. Elderly Individuals with Cognitive Disorders:
    Imagine an elderly person suffering from dementia or Alzheimer's disease. Their mental capacity may be compromised, making it difficult for them to comprehend the rights, obligations, and consequences of a contract. In such cases, if it can be proven that the other party was aware or should have been aware of the person's incapacity, the contract may be set aside.

Example: An elderly person with dementia signs a contract to sell their property without fully understanding the implications. If the buyer was aware of the person's condition, the contract may be deemed voidable.

  1. Individuals Under Management Orders:
    When a person's financial affairs are being managed due to their incapacity, any contracts or transactions they enter into may be subject to scrutiny. If it can be shown that the person lacked the capacity to understand the transaction, and the other party was aware of this, the contract may be set aside.

Example: A person under a financial management order signs a contract to invest a large sum of money without comprehending the risks involved. If the other party was aware of their incapacity, the contract may be voidable.

  1. Undue Influence and Unconscionability:
    In some cases, contracts or gifts may be challenged on the grounds of undue influence or unconscionability. Undue influence refers to situations where one party exerts pressure or manipulates another party into entering an agreement. Unconscionability arises when one party takes advantage of another's special disadvantage, such as age or mental impairment.

Example: An elderly person, heavily reliant on their caregiver, is coerced into signing a contract that heavily favors the caregiver. If it can be proven that the caregiver exerted undue influence, the contract may be set aside.

Medical evidence

Having evidence available about these issues is critical, and the formulation of it playes a key role. It is not simply enough to ask a doctor for an opinion as key matters need to be addressed. 

Conclusion:
The law recognizes the vulnerability of individuals lacking capacity and provides mechanisms to protect their interests. Contracts, gifts, and transactions entered into by individuals with compromised mental capacity can be set aside if certain conditions are met. Whether it's the elderly, individuals under management orders, or those subjected to undue influence, the law aims to ensure fairness and protect the rights of those lacking capacity.