Barker's Tidal Model of Mental Health Recovery is a middle-range theory of nursing that can be used as the basis for interdisciplinary health care. The main focus of the model is on helping individual patients create their own voyage of discovery.

Phil Barker defines the Tidal Model as "a philosophical approach to the discovery of mental health. It emphasises helping people reclaim the personal story of mental distress, by recovering their voice. By using their own language, metaphors and personal stories people begin to express something of the meaning of their lives. This is the first step towards helping recover control over their lives." It provides a nursing care practice framework for the exploration of the patient's need for nursing and the provision of individually-tailored care plans. The theory states that an individual's mental well-being is dependent on his or her individual life experiences, including his or her sense of self, perceptions, thoughts, and actions.

The main philosophical metaphor is drawn from chaos theory. That is, the unpredictable, yet unbounded, nature of human behavior and experience is compared to the dynamic flow and power of water and the tides of the sea.

There are six key philosophical assumptions in Barker's Tidal Model:

a belief in the virtue of curiosity recognition of the power of resourcefulness, instead of focusing on problems, deficits, or weaknesses respect for the patient's wishes instead of being paternalistic acceptance of the paradox of crisis as opportunity acknowledging that all goals must belong to the individual patient the virtue of pursing elegance: the simplest possible means should be sought

In order for the nurse to begin the process of engagement using the Tidal Model, the following needs to be accepted:

recovery is possible change is inevitable ultimately, the patient knows what is best for him or her the patient possesses all the resources he or she needs to begin the recovery journey the patient is the teacher, while the helpers are the pupils the helper needs to be creatively curious, and to learn what needs to be done to help the person

The process of engaging with the patient takes place in three different domains: self, world, and others. The nurse explores these dimensions to increase awareness of the situation in the present and determine what needs to occur at that moment.

The self domain is where people feel their world of experiences. This includes an emphasis on making people feel more secure, and the nurse helps the patient develop a security plan to reduce threats to the patient or those around him or her.

The world domain is where the patient holds his or her story. The nurse uses a specific form of inquiry to explore the story collaboratively, revealing its hidden meanings, the patient's resources, and to identify what needs to be done to help the patient recover.

The others domain represents the different relationships of the patient, including past, present, and future. This includes the nurse as well as other members of the health care team, friends, family, and other supporters.

The Ten Commitments of the Tidal Model are the values it expresses. They are:

Value the voice-the patient's story is paramount Respect the language-allow the patient to use his or her own language Develop genuine curiosity-show interest in the patient's story Become the apprentice-learn from the patient you are helping Reveal personal wisdom-a patient is an expert in his or her own story Be transparent-help ensure that the patient understands exactly what is being done Use the available toolkit-the patient's story contains valuable information as to what works and what does not work Craft the step beyond-the nurse and the patient work together in order to construct an appreciation of what needs to be done "now" Give the gift of time-time is the midwife of change, and the key is using the time properly Know that change is constant-this is a common experience for all people

There are also twenty competencies associated with the ten commitments. They assist with the auditing of recovery practice by creating practice-based evidence for the theory. There are two for each commitment, and they focus on competencies in practice.,

The Tidal Model of Mental Health Recovery uses the theme of water throughout. It describes how patients in distress can become "shipwrecked" emotionally, physically, and spiritually. The experience of health and illness is a fluid phenomenon rather than a stable one, and life is considered a journey gone through on an ocean of experience.

The theory proposes that in mental health nursing, the factors having to do with psychiatric crisis can be cumulative as well as diverse. It states that by appreciating the water metaphor, nurses can gain a better understanding of the patient's immediate situation and the inevitability of change. Through this, the nurse can be guided to care with the patient beginning his or her journey in a shipwrecked state caused by life problems. Following the rescue, exploration can begin to find out what caused the "storm" in the first place, then figure out what needs to be done in order to "set sail" again.