Release therapy

1. Introduction

Version followed: David M. Levy's release therapy of the 1930s, as later play-therapy writers summarise it (Kwak 2000; Crenshaw; Chauhan et al. 2024; Bratton et al. 2009), plus Heidi Gerard Kaduson's present-day "Release Play Therapy" for single-incident trauma, known here only from course and contents pages. Several independent secondary sources confirm the core sequence. The child plays freely first. The therapist then introduces a limited set of toys that resemble the specific stressful event, and the child is not forced to use them. Levy's own papers (1933, 1936, 1938, 1939) are not drawn on here. The 1938 citation details were confirmed from reference lists. The 1939 paper's journal details, Levy's "three types" of release, his selection criteria and any session count were not found in any legitimate source and remain [uncertain]. Practical steps added for safe current use are marked [synthesis].

What it is. Release therapy is a directive, structured form of play therapy for young children. David M. Levy (1892–1977) was a New York child psychiatrist. He was chief of staff of the New York Institute for Child Guidance and opened a private practice in New York in 1933. His papers credit him with originating play therapy, "which he also called 'release therapy'", and with "activity play therapy", in which children act out emotions through play [source: David Levy MD Papers finding aid]. Levy's play papers that later authors cite are these. All are [uncertain]:

• "Use of play technic as experimental procedure", American Journal of Orthopsychiatry, 3(3), 1933.
• "Hostility patterns in sibling rivalry experiments", American Journal of Orthopsychiatry, 6(2), 1936.
• "'Release therapy' in young children", Psychiatry, 1(3): 387–390, 1938, doi 10.1080/00332747.1938.11022205. These details come from the Wikipedia "Play therapy" reference list. Gupta et al. (2023) give the same pages but misprint the year as 1983.
• Studies in Sibling Rivalry, a 96-page American Orthopsychiatric Association monograph from 1937.

[source: Mayers & Mayers 1941 reference list; Gupta et al. 2023; Wikipedia "Play therapy" reference list; Malcove 1938 review listing]. Bratton et al. (2009) also cite a 1939 Levy paper titled "Release Therapy". Searches of APA PsycNet, Wiley and other legitimate pages did not confirm its journal, volume or pages [uncertain].

Core idea of change. The child has been through a specific stressful or frightening event. The child first plays freely. Once the child is comfortable, the therapist introduces play materials related to that event, so the child can re-enact it and release the feelings tied to it [source: Wikipedia "Play therapy", summarising Levy 1938; Chauhan et al. 2024]. The therapist provides only toys suited to expressing the emotionally meaningful event, and does not force the child to use them. With a sense of safety and support, repeated re-enactment lets the child digest the negative thoughts and feelings tied to the event [source: Kwak 2000, Korean, paraphrased]. Crenshaw says the toys are chosen to closely resemble the traumatic experience, and that the name reflects Levy's emphasis on abreaction [source: Crenshaw, Psychotherapy Networker]. That article wrongly calls Levy British; his papers show he was a New York psychiatrist [source: Levy Papers finding aid]. The aim is to stimulate catharsis, meaning the release of pent-up feeling, in play [source: Bratton et al. 2009]. Later summaries describe three kinds of release:

• simple release of aggressive impulses;
• release of feelings in a standard set-up, such as sibling rivalry;
• release of feelings by re-creating the child's own stressful experience with toys.

[uncertain: this three-part list came from a secondary slide upload that has since been removed. None of the sources lists these three types: Kwak 2000, Chauhan et al. 2024, Crenshaw, Wikipedia, Bratton et al. 2009 and Gupta et al. 2023. Only the third type, re-creating the child's own stressful event, is confirmed.] Kaduson's current version presents release play as a way to help children with PTSD after a single traumatic event (Type I trauma) work through and master that event. It uses directive techniques, Freud's idea of abreaction (reliving an experience to discharge the feeling tied to it) and work on irrational thinking [source: Play Therapy Training Institute course pages].

Status today. The original method is mainly historical. It survives mostly as an ancestor of directive and trauma-focused play therapies. The catharsis assumption has been questioned. Terr's (1981) work on post-traumatic play found that compulsive literal re-enactment often fails to relieve anxiety. Later authors warn that unproductive repetitive trauma play can worsen the effects of trauma [source: D'Elia et al. 2022]. Use the method only within modern trauma-informed practice (see sections 2–5).

2. Framework

The sources give no manual-level phase structure, session count or criteria for moving between phases. The documented sequence has two steps. First the child plays freely until comfortable. Then the therapist introduces materials related to the stressful event [source: Wikipedia "Play therapy"; Chauhan et al. 2024]. The method is described for a child who has experienced a specific stressful situation [source: Wikipedia, summarising Levy 1938]. It is also described as suiting children whose emotional expression is held back, or who need to discharge the feeling tied to a traumatic event [source: Kwak 2000]. Levy's own fuller selection criteria, such as age limits or family conditions, were not found [uncertain]. The framework below combines the documented sequence with standard current safeguards, which are marked [synthesis].

Format: individual sessions with the child, plus separate caregiver meetings [synthesis; Bratton et al. 2009 for caregiver meetings in play therapy generally]. Kaduson's chapter appears in a book titled Short-Term Play Therapy for Children, which places it among brief approaches [source: Guilford contents page]. No session count was found, either Levy's or one specific to release therapy [uncertain]. Chauhan et al. (2024) give a range from 15–20 sessions to 1–2 years, but that range is for play therapy in general, not for release therapy.

3. Guiding principles

• The therapist directs the materials. You choose and present a limited set of toys related to the stressful event, rather than waiting for the child to pick. You structure the play situation to set the stage for catharsis [source: Bratton et al. 2009; Chauhan et al. 2024; Kwak 2000]. In practice, plan the set-up before the session from the history.
• Offer, do not force. Only toys suited to the event are given, but the child is not compelled to use them [source: Kwak 2000]. In practice, the child stays free to ignore or stop the scene (see section 5, avoidance or refusal).
• Specificity. Release play targets a specific stressful event or situation [source: Wikipedia summarising Levy 1938; Kwak 2000; PTTI "Type I trauma"]. In practice, do not use it for chronic, multiple or ongoing abuse; refer to broader trauma-focused care [synthesis].
• Play is the child's natural way of coping. Kaduson describes the method as using "the child's natural methods of dealing with difficulties" [source: PTTI workshop page]. In practice, let the child set the action and words inside the scene you offer.
• Mastery, not just discharge. Current writers value play in which the child changes the trauma's negative elements and reaches calm. Repetition that brings no relief is a warning sign [source: D'Elia et al. 2022]. In practice, judge each session by change in the play, not by how much emotion the child shows.
• Safety and relationship first. Current best practice in trauma play stresses safety, shared attention and the social engagement system [source: D'Elia et al. 2022]. Kwak's summary of Levy also places re-enactment within security and support [source: Kwak 2000]. In practice, never begin a re-creation until the child is settled with you and has a way to stop.
• Correct the child's thinking about the event. Kaduson's version includes countering irrational thinking about the trauma [source: PTTI workshop page]. In practice, name and correct self-blame or false beliefs that come up in play, in words the child can follow.
• Play is not evidence. Never read a child's play as proof that abuse or a disorder exists. Play material is a clinical observation, not forensic evidence [synthesis]. In practice, record what the child did and said, word for word, without interpreting it.
• Caregivers are partners. In practice, keep caregivers informed of themes (not the details of play) and of what to expect at home [source: Bratton et al. 2009, CCPT parent practice; synthesis for release therapy].

4. Intervention inventory

The sources describe the procedures only in outline. Steps marked [synthesis] are general good practice for carrying out what the sources describe. They are not Levy's or Kaduson's own instructions.

4.1 History-taking and planning the set-up

• Purpose: Find the specific event or situation behind the symptoms and choose matching toys. The toys are chosen to closely resemble the traumatic experience [source: Crenshaw; Kwak 2000], so the therapist must know the event first. The history-taking steps below are [synthesis].
• Steps:
  1. Interview the caregiver alone about the event: date, setting, people, objects, sounds, how the child reacted, and what happened afterwards.
  2. List current symptoms with frequency, such as nightmares, avoidance, clinginess, re-enactment and regression. Use these as a baseline.
  3. Screen for ongoing danger, other traumas, developmental delays and medical issues.
  4. Choose a small, deliberate set of toys that can represent the people and objects, plus neutral and comforting toys. Choose deliberately and reflect the child's culture [source: Bratton et al. 2009 on toy selection in play therapy generally].
  Steps 1–3 [synthesis].
• Example language (illustrative): "Tell me what happened, as close to the order it happened in as you can. What did they see and hear?"
• Watch for: Several or ongoing traumas. Caregivers who were part of the event or are still frightened by it. Any safeguarding concern. Each of these points away from release play, towards a fuller assessment and broader trauma treatment [synthesis].

4.2 Caregiver preparation, consent and child assent

• Purpose: Make sure caregivers agree to the directive approach, know what to expect and support the child between sessions.
• Steps:
  1. Explain the plan in plain words and say how it differs from free play. Give the reasons and the possible short-term rise in symptoms.
  2. Get informed consent from the person with parental responsibility. Explain the limits of confidentiality, including your duty to act on safeguarding concerns.
  3. Agree how often you will review progress. Monthly caregiver consultations of about 30 minutes are recommended in child-centred play therapy [source: Bratton et al. 2009].
  4. Get the child's assent in age-appropriate words, and tell the child they can stop.
  Steps 1, 2 and 4 [synthesis].
• Example language, to the child (illustrative): "This is a playroom. Sometimes I'll bring out special toys about the thing that happened to you. You can play with them, or tell me 'stop', and we'll play something else."
• Watch for: A caregiver who pushes the child to "talk about it" at home. Ask them to avoid questioning and to report behaviour instead [synthesis].

4.3 Engagement and readiness sessions

• Purpose: Build safety and a baseline before any directive set-up. In Levy's sequence as summarised, the child plays freely until comfortable before the therapist introduces trauma-related toys [source: Wikipedia "Play therapy"; Chauhan et al. 2024]. Safety as a foundation follows D'Elia et al. 2022.
• Steps:
  1. Run one or more sessions of mostly child-led play.
  2. Name feelings as they come up.
  3. Teach one calming routine, such as slow breathing with a pinwheel or a cuddle toy.
  4. Agree a stop signal.
  [synthesis]
• Example language (illustrative): "When you want to stop, you can hold up the red card, and we'll go to the quiet corner."
• Watch for: Whether the child can calm down with your help. If not, delay release work [synthesis].

4.4 Simple release play

• Purpose: Let the child release aggressive or pent-up impulses through safe actions. A removed secondary source gave throwing objects and bursting balloons as examples. No source opened in the re-check describes this form of release [uncertain: not verified; treat this whole intervention as unconfirmed].
• Steps:
  1. Offer safe materials such as soft balls, clay to pound, or paper to tear.
  2. Set clear limits: people and windows are never targets.
  3. Let the child act. Reflect the feeling, not the action.
  4. End with a calming activity.
  [synthesis; materials safety in 4.10]
• Example language (illustrative): "You're throwing really hard. You're really angry. It's OK to throw at the target, not at people."
• Watch for: Escalation that does not settle, or arousal still high at the end. Shorten and contain if so [synthesis]. A sign it is working: the child can start and stop, and more often tells you the feeling in words [synthesis].

4.5 Standard-situation release (for example, sibling rivalry)

• Purpose: Present a set scene that evokes a common family feeling so that the child can express it. The example of a baby doll at a mother doll's breast, used to evoke sibling rivalry, came from a removed secondary source. It was not found in any source opened in the re-check [uncertain: not verified]. Levy did publish play experiments on sibling rivalry: a 1936 paper, and a 1937 monograph reviewed by Malcove in 1938. Their content is not drawn on here [uncertain].
• Steps:
  1. Set out the figures: a mother doll, a baby doll feeding, and a child doll representing the client.
  2. Make a neutral opening statement.
  3. Follow what the child does. Reflect feelings such as jealousy, wish and guilt.
  4. Correct guilt where the child shows it.
  Steps 2–4 [synthesis].
• Example language (illustrative): "Here's a mummy and a new baby. And here's a big sister. What does the big sister do?" Later: "She's really cross with the baby. Lots of big sisters feel that. Feeling it doesn't make anything bad happen."
• Watch for: Distress that goes beyond the scene, or a family situation that is actually unsafe [synthesis].

4.6 Re-creating the specific stressful experience

• Purpose: Present the child's own frightening experience in play, so the child can re-enact it and express the feelings tied to it. This is the core and best-documented form of Levy's method [source: Wikipedia summarising Levy 1938; Chauhan et al. 2024; Kwak 2000; Crenshaw; Bratton et al. 2009 on toys used to stimulate catharsis]. Kaduson's version targets single-incident PTSD [source: PTTI course pages].
• Risk flag: This is the step most open to the concerns later writers raise. Unchanging literal re-enactment can fail to relieve anxiety and may worsen the effects of trauma [source: D'Elia et al. 2022, citing Terr 1981]. Re-exposing a very young child without preparation, consent and a way to stop is not acceptable practice [synthesis]. Kwak's summary says Levy's re-enactment takes place within security and support, and that the child is not forced [source: Kwak 2000]. No source opened gives Levy's own concrete safeguards for this step [uncertain].
• Steps:
  1. Do this only after 4.1–4.3 [synthesis].
  2. Build the scene in small pieces, moving from least to most evocative. Show a few figures first and add the key object, such as a toy dog, car or doctor kit, only if the child is engaged [synthesis].
  3. Introduce the scene briefly and neutrally. Do not narrate the trauma for the child [synthesis].
  4. Let the child lead what happens. Track and reflect what you see and the feelings [synthesis].
  5. Watch arousal throughout. Use the stop signal and calming routine as needed [synthesis].
  6. Close every session in a neutral state (4.9) [synthesis].
• Example language (illustrative): "Here's a little boy, and here's a big dog. You can show me what happens." Then: "The dog jumped and the boy was so scared. ... Now the boy is getting help."
• Watch for: The play becoming varied over sessions, with protectors, rescue, new endings and calm. This indicates processing. Fixed, joyless and identical repetition with no relief indicates negative post-traumatic play [source: D'Elia et al. 2022 markers]. Also watch for dissociation, such as freezing, a glazed look or losing contact, and for new symptoms at home [synthesis].

4.7 Abreactive release play with cognitive correction (Kaduson's version)

• Purpose: Help a child with single-incident PTSD regain resilience, through directive techniques that bring on abreactive play and through countering irrational thinking about the event [source: PTTI workshop and course pages]. Kaduson's detailed steps are in her 2015 chapter and in recorded course material. Neither is drawn on here, so the steps below are not hers [uncertain].
• Steps (synthesis):
  1. Run the re-creation as in 4.6.
  2. When the child's play or words show a mistaken belief, name it and correct it simply and concretely. Typical beliefs are "it was my fault", "it will happen again any minute" or "I'm bad".
  3. Repeat the correction across sessions. Share it with caregivers so that they can repeat it at home.
• Example language (illustrative): "The boy thinks the dog bit him because he was naughty. Dogs don't bite because children are naughty. It wasn't his fault."
• Watch for: Whether the corrected belief shows up in the child's later play or talk [synthesis].

4.8 Tracking post-traumatic play and moving it towards new endings

• Purpose: Tell productive from unproductive trauma play, and step in when play is stuck. Terr (1981) described post-traumatic play as compulsively repetitive, literal, failing to relieve anxiety and without happy endings. In positive post-traumatic play, the child changes the negative elements and reaches calm. In negative post-traumatic play, repetition brings no relief and may cause regression [source: D'Elia et al. 2022]. The therapist can let processing happen naturally or guide structured or semi-structured play so that the event is relived with a more adaptive result [source: D'Elia et al. 2022].
• Steps (synthesis):
  1. After each session, note how literal and repetitive the play was, the child's mood at the end, any new elements and changes in symptoms.
  2. If the play is the same for two or three sessions, step in gently. Bring in a helper figure. Ask what the character needs. Offer a change, such as "What if the ambulance came?"
  3. If it is still stuck, stop the re-creation and return to stabilisation. Review the case in supervision.
• Example language (illustrative): "The girl is hiding again. I wonder who could come and help her this time."
• Watch for: Positive signs: new characters, rescue, the child taking the powerful role, and calm at the end. Negative signs: the same sequence every time, flat or frantic mood, and nightmares or regression getting worse [source: D'Elia et al. 2022 for markers; synthesis for the working criteria].

4.9 Closure and containment at the end of each session

• Purpose: Make sure the child leaves regulated [synthesis].
• Steps (synthesis):
  1. Give a five-minute warning.
  2. Help the child put the trauma figures away in a box or behind a cloth.
  3. Do the calming routine.
  4. Do a short neutral or pleasant activity.
  5. Hand over to the caregiver with a brief, non-detailed update. Ask them to report sleep and behaviour.
• Example language (illustrative): "Let's put the dog and the car to sleep in their box until next time. Now let's do our balloon breaths."
• Watch for: The child still being distressed at handover. Extend calming time and phone the caregiver later that day [synthesis].

4.10 Practice frame and safety

These points apply to every intervention above.

• Training and credential. No separate credential exists for release therapy. Use it only as a qualified mental-health professional trained in play therapy and in child trauma, with supervision [synthesis]. In the US, the Association for Play Therapy (APT) awards the RPT and RPT-S credentials and approves continuing education. Kaduson holds the RPT-S, and her release play courses are APT-approved for continuing education [source: PTTI pages]. In the UK, play therapy bodies such as BAPT and PTUK hold registers [uncertain: their requirements were not checked]. Do not use directive trauma re-creation without child-trauma training [synthesis].
• Safeguarding and mandatory reporting. Where the history or the play suggests current abuse or neglect, follow your jurisdiction's child-protection procedures. Mandatory-reporting duties differ by country, state and profession, so know your local law and agency policy [synthesis]. Tell caregivers and the child about the limits of confidentiality at the start. Write down the child's spontaneous words and actions as they occurred. Do not ask leading questions. Do not turn play into an investigative interview; forensic interviewing is a separate, specialised role [synthesis]. Play themes are not evidence of abuse [synthesis].
• Consent and assent. Consent comes from the person with parental responsibility; check custody arrangements. Seek the child's assent in age-appropriate language and respect a refusal or a stop signal at any point [synthesis].
• Parent or caregiver involvement. Meet caregivers before starting and at regular intervals [source: Bratton et al. 2009]. Share themes, not the details of play. Guide caregivers on responding to after-effects at home [synthesis]. When a caregiver is very distressed by the event, refer them for their own support [synthesis].
• Touch. Keep physical contact to what the child initiates and what is needed for safety or comfort, such as a brief hand on the shoulder or helping a fallen child. Ask first where you can. Never restrain except in an immediate safety emergency under your service's policy. Never engage in sexual or genital touch, and do not stage scenes that involve the child's or the therapist's body. Represent bodily trauma, such as a medical procedure or an assault, only with dolls and figures [synthesis]. Take account of cultural norms about touch and of how trauma affects the child's response to it [synthesis].
• Materials safety. Latex balloons and small parts are choking hazards for young children, and latex can cause allergic reactions. Use non-latex balloons inflated and handled by the adult, or swap in bubble wrap or soft foam [synthesis]. Provide soft throwing objects only, keep sharp tools such as toy knives and scissors under supervision, and use non-toxic clay and paints. Clean toys between clients. Keep the room free of hazards, such as heavy items that could fall or items that could be used to hurt oneself [synthesis]. Choose toys deliberately and avoid mechanical toys [source: Bratton et al. 2009].

5. Handling problems

The sources say almost nothing about troubleshooting. Responses below are [synthesis] unless they carry a source tag.

• Overwhelm or flooding during a re-creation. Signs include panic, screaming, freezing, a glazed stare, wetting or running out. Stop the directive scene right away and remove or cover the trauma toys. Use the agreed calming routine, and move nearer only if the child welcomes it. Return to neutral play. Do not resume the scene in that session. Next time, go back to stabilisation, then rebuild the scene in smaller steps [synthesis].
• Stuck, repetitive play that brings no relief (negative post-traumatic play) can worsen the effects of trauma [source: D'Elia et al. 2022]. Respond as in 4.8: bring in helpers, offer new endings, and if nothing changes, stop the re-creation and reassess. Check for ongoing danger or further trauma you have not been told about [synthesis].
• Avoidance or refusal (the child ignores the set-up toys or says "no"). Respect it. That is part of assent. Leave the toys available but not in the centre. Return to child-led play and reintroduce the scene later in a milder form. Never push a child into re-enactment [synthesis].
• Symptoms worsen at home (more nightmares, clinging or tantrums). Warn caregivers in advance that this may happen for a short time. If it lasts beyond about two weeks or is severe, pause release work and reassess [synthesis: the two-week figure is a clinical rule of thumb, not sourced].
• Aggression that spills over (in simple release play the child targets you or breaks things). Restate the limit and redirect to the permitted target. If needed, end the activity and do not reward escalation. Keep limits consistent across sessions [synthesis].
• Disclosure during play (the child shows or says something suggesting abuse). Stay calm and listen without leading. Do not interrogate. Write down the exact words, then follow safeguarding procedures the same day [synthesis].
• Caregiver non-adherence (missed sessions, questioning the child at home, or rejecting the directive approach). Revisit the rationale. Give specific instructions on what to say and what to avoid. Consider a non-directive or caregiver-focused approach instead if they cannot support directive work [synthesis].
• Rupture with the child (the child becomes angry or distrustful after a hard session). Name it simply: "Last time was hard. I'm sorry it felt too much." Let the child lead the next session [synthesis].
• Wrong case for this method. Chronic, multiple or relational trauma, ongoing abuse, a child placed in care, major developmental delay or dissociation all call for a broader trauma-focused approach rather than release play. Release play is described here for single-incident (Type I) trauma [source: PTTI course pages; synthesis for exclusions].
• Current trauma-focused play approaches to consider instead or in combination (names from sources; methods not reviewed here):
  • Kaduson's Release Play Therapy for single-incident PTSD [source: PTTI course pages].
  • Pifalo & Hamil's short-term trauma resolution combining art and play therapy [source: Guilford contents].
  • Goodyear-Brown's play-based trauma approaches [source: D'Elia et al. 2022, citing Goodyear-Brown 2010, 2019].
  • EMDR with children, combined with other approaches [source: D'Elia et al. 2022, citing Gomez 2012].
  • Child-centred play therapy, for which a systematic review in traumatised youth exists [source: D'Elia et al. 2022, citing Humble et al. 2019].
  • Theraplay and cognitive-behavioural play therapy [source: Guilford contents].
  • Trauma-focused CBT and child–parent psychotherapy are widely used for young children [synthesis; uncertain].

Sources

Sources:

• David Levy MD Papers, 1914–1977, bulk 1930–1950 (finding aid)
• Gupta N, Chaudhary R, Gupta M, et al. (2023). Play therapy as effective options for school-age children with emotional and behavioral problems: a case series. Cureus 15(6): e40093
• Mayers AN, Mayers EB (1941). Dynamic-concept test: quantitative modified play technique for adults. Psychiatric Quarterly 15(4): 621–634 (reference list used)
• Malcove L (1938). Review of Levy, Studies in Sibling Rivalry. Psychoanalytic Quarterly 7: 148–151 (listing only)
• Bratton SC, Ray DC, Edwards NA, Landreth G (2009). Child-centered play therapy (CCPT): theory, research, and practice. Person-Centered and Experiential Psychotherapies 8(4): 266–281
• D'Elia D, Carpinelli L, Savarese G (2022). Post-traumatic play in child victims of adverse childhood experiences: a pilot study with the MCAST. Children 9(12): 1991
• Kwak YS (2000). Play psychotherapy [in Korean]. Korean Journal of Child & Adolescent Psychiatry 11(2): 161–178
• Chauhan N, Sachdeva D, Malhotra S, Gupta N (2024). Play therapy: an analytical mode of therapy in children. SAGE journal article
• Crenshaw D, with commentary by Diller L. The healing power of play. Psychotherapy Networker
• Wikipedia: Play therapy (history section and Levy 1938 reference entry; tertiary source)
• Play Therapy Training Institute: Release Play Therapy workshop (Kaduson)
• Working Through Traumatic Events: Release Play Therapy in Action (Kaduson course page)
• Course Description and Learning Objectives (Kaduson course)
• Guilford Press: Short-Term Play Therapy for Children, 3rd ed., contents
• Anonymous play-therapy slide presentation on a user-upload document-sharing site: link removed and not relied on. Claims formerly cited to it were re-checked in October 2026; those still unconfirmed are marked [uncertain].
• Levingston K (2015). Play therapy. In SAGE Encyclopedia of Theory in Counseling and Psychotherapy (opening only)

Further reading (not drawn on):

• Levy DM (1933). Use of play technic as experimental procedure. American Journal of Orthopsychiatry 3(3).
• Levy DM (1936). Hostility patterns in sibling rivalry experiments. American Journal of Orthopsychiatry 6(2).
• Levy DM (1937). Studies in Sibling Rivalry. American Orthopsychiatric Association monograph.
• Levy DM (1938). "Release therapy" in young children. Psychiatry 1(3): 387–390. doi:10.1080/00332747.1938.11022205 (citation confirmed from reference lists; DOI page not drawn on).
• Levy DM (1939). Release therapy [cited by Bratton et al. 2009; journal, volume and pages not confirmed in the re-check, uncertain].
• Kaduson HG (2015). Release play therapy for children with posttraumatic stress disorder. In Kaduson HG, Schaefer CE (eds), Short-Term Play Therapy for Children, 3rd ed. Guilford.
• Terr L (1981), on post-traumatic play [cited via D'Elia et al. 2022; title not confirmed, uncertain].