Play therapy refers to a range of methods of capitalising on children's natural urge to explore and harnessing it to meet and respond to the developmental and later also their mental health needs.

It is also used for forensic or psychological assessment purposes where the individual is too young or too traumatised to give a verbal account of adverse, abusive or potentially criminal circumstances in their life.

They provide a contained way for them to express their experiences and feelings through an imaginative self-expressive process in the context of a trusted relationship with the care giver or therapist.

[13] The objects and patterns of play, as well as the willingness to interact with the therapist, can be used to understand the underlying rationale for behaviour both inside and outside of therapy session.

The hope is that through the language of symbolic play, such desensitisation may take place, as a natural part of the therapeutic experience, and lead to positive treatment outcomes.

[26] Arguably, the first documented case, describing a proto-therapeutic use of play, was in 1909 when Sigmund Freud published his work with "Little Hans", a five-year-old child suffering from a horse phobia.

It is guided by the notion that if given the chance to speak and play freely in appropriate therapeutic conditions, troubled children and young people will be helped towards resolving their difficulties.

[37] These approaches to therapy may originate from Margaret Lowenfeld, Anna Freud, Donald Winnicott, Michael Fordham, Dora Kalff, all of them child specialists or even from the adult therapist, Carl Rogers' non-directive psychotherapy and in his characterisation of "the optimal therapeutic conditions".

[39] Jungian analytical method of psychotherapy using a tray of sand and miniature, symbolic figures is attributed to Dr. Margaret Lowenfeld, a paediatrician interested in child psychology who pioneered her "World Technique" in 1929, drawn from the writer H. G. Wells and his Floor Games published in 1911.

This protocol emphasises the importance of holding what Kalff referred to as the "free and protected space" to allow the unconscious to express itself in symbolic, non-verbal play.

Upon completion of a tray, the client may or may not choose to talk about his or her creation, and the therapist, without the use of directives and without touching the sandtray, may offer supportive response that does not include interpretation.

For Winnicott, one of the most important and precarious stages of development was in the first three years of life, when an infant grows into a child with an increasingly separate sense of self in relation to a larger world of other people.

[51][52] Recent play therapy researchers have worked to conduct more experimental studies with larger sample sizes, specific definitions and measures of treatment, and more direct comparisons.

[50] Outside of the psychoanalytic child psychotherapy field, which is well annotated,[53][54] research is comparatively lacking in other, or random applications, on the overall effectiveness of using toys in non-directive play therapy.

[40] However, other research shows that following specific criteria when choosing toys in non-directive play therapy can make treatment more efficacious.

Meta analysis by authors Ray, Bratton, Rhine and Jones, 2001, found an even larger effect size for nondirective play therapy, with children performing at 0.93 standard deviations better than non-treatment groups.

[36] Meta analysis by authors Bratton, Ray, Rhine, and Jones, 2005, also found a large effect size of 0.92 for children being treated with non-directive play therapy.

[57] Parental involvement in play therapy sessions has also been shown to diminish stress in the parent-child relationship when kids are exhibiting both internal and external behaviour problems.

Subsequently, the therapist would introduce play materials related to the stress-evoking situation allowing the child to reenact the traumatic event and release the associated emotions.

In directive therapy games are generally chosen for the child, and children are given themes and character profiles when engaging in doll or puppet activities.

Counselor-educators such as Alexander (1964); Landreth;[67][68] Muro (1968); Myrick and Holdin (1971); Nelson (1966); and Waterland (1970) began to contribute significantly, especially in terms of using play therapy as both an educational and preventive tool in dealing with children's issues.

Roger Phillips, in the early 1980s, was one of the first to suggest that combining aspects of cognitive behavioral therapy with play interventions would be a good theory to investigate.

[69] In this therapy, specific toys such as dolls and stuffed animals may be used to model particular cognitive strategies, such as effective coping mechanisms and problem-solving skills.

[64] Creating stories with the dolls and stuffed animals is a common method used by cognitive behavioral play therapists to change children's maladaptive thinking.

[83] There are also studies that found role-playing games, when combined with the Adlerian Play Therapy (AdPT) techniques, lead to increased psychosocial development.

[82] A biofeedback game initially designed to assist with anxiety symptoms, Relax to Win, was similarly found to have broader treatment applications.

[89] Several online-only or mobile games (Re-Mission, Personal Investigator,[90] Treasure Hunt,[91] and Play Attention)[92] have been specifically noted for use in alleviating disorders other than those for anxiety and mood.

[88] In the future, clinicians may look forward to using electronic media as a way to assess patients,[89] as a motivational tool,[99] and facilitate social in-person and virtual interactions.

[104] Play therapy is an evidence based approach for children that allows them to find ways to learn, process their emotions, and make meaning of the world around them.

[112] In 2006, Garry Landreth and Sue Bratton developed a highly researched and structured way of teaching parents to engage in therapeutic play with their children.