The PSI Code of Professional Ethics consists of four overall ethical principles, which subsume a large number of specific ethical standards.
Principle 1: Respect for the rights and dignity of the person
This principle requires of psychologists that they treat their clients as persons of intrinsic worth with a right to determine their own priorities, that they respect clients' dignity, and give due regard to their moral and cultural values. Psychologists shall take care not to intrude inappropriately on clients' privacy. They shall treat as confidential all information (including oral, verbal, written and electronic) obtained in the course of their work, except where the law requires disclosure. As far as possible, they shall ensure that clients understand and consent to whatever professional action they propose.
Principle 2: Competence
Psychologists must constantly maintain and update their professional skills and ethical awareness. They shall recognise that psychological knowledge and their own expertise and capacity for work are limited, and take care not to exceed the limits.
Principle 3: Responsibility
In their professional and scientific activities, psychologists are required to act in a trustworthy, reputable, and accountable manner towards clients and the community. They shall avoid doing harm to clients and research participants, and act to prevent harm caused by others. They shall co-operate with colleagues and other professionals to ensure the best service to clients, and act positively to resolve ethical dilemmas. They shall ensure that those whom they supervise act ethically. In research with animals, they shall take care to treat the animals humanely.
Principle 4. Integrity
Psychologists are obliged to be honest and accurate about their qualifications, the effectiveness of the services which they offer, and their research findings. They shall take steps to manage personal stress and maintain their own mental health. They shall treat others in a fair, open and straightforward manner, honour professional commitments, and act to clarify any confusion about their role or responsibilities. Where possible, they shall avoid the use of deception with research participants. They shall not use the professional relationship to exploit clients, sexually or otherwise, and they shall deal actively with conflicts of interest. They shall take action against harmful or unethical behaviour in colleagues or members of other professions.
The full Code of Ethics is available here