Sleepwalking (Somnambulism) is a state of dissociated consciousness triggered by impaired arousal, characterized by hypnologic state of partial wakefulness and partial sleep, and occurs typically at the transition episode from deep non-rapid eye movement (NREM) stage into rapid eye movement (REM) stage ^[1]. The episode prior to REM stage is similar with the dream state that is emotionally charged for alleviation of psychological stress. Besides, the unconsciousness of the individuals can not be recognized. The classification of sleep stages can explain why somnambulism occurs mostly at the first one third of the night with complete amnesia ^[2]. Psychiatrists may identify a defense mechanism in the visitor for further psychotherapy against trauma associated with somnambulism, if somnambulism is thought to be a special form of dream that can be recorded by others^[3].

According to a recent meta-analysis, the estimated lifetime prevalence of somnambulism is 6.9%, and it occurs most commonly in childhood and adolescence (from 4 to17 years), where NREM sleep is in the most active stage^[4]; its prevalence decreases significantly in adulthood ^[5]. Although evidences show that this neurogenic disease disappears spontaneously after adolescence, the symptoms of the traumas caused by sleepwalking still need attention^[6]. Currently no effective treatments or medications have been available for treating somnambulism in childhood, which can be the optimal time window for intervention ^[7]. Herein we present a case of somnambulism in a 4.5-year-old girl treated successfully with individualized psychotherapy.

A 4.5-year-old girl was presented to our outpatient department for repeated sleepwalking and mumbling in the last week. The girl lived with her grandparent every day and her parents had only limited time (2 days a week) to keep her company. Normally, she required the company by a family member (one of her grandparents or parents) to sleep, otherwise she would appear upset and cry. She also had these behaviors on her way to kindergarten. At night, for no obvious reasons, she got up about 1 h after falling asleep. In most cases, she crept along the bedside nervously, crying and sweating; occasionally, she switched a light on and off with unrecognized mumbling. The whole process, lasting from several to more than 10 min, ended up with her creeping back to sleep in tears. She did not recall any of these abnormal behaviors in the daytime, and the nursery governess did not report any abnormal behaviors during the nap at noon in the kindergarten. Her parents considered that mental stress caused the abnormality and sought medical attention in the outpatient clinic.

The girl, born full-term by vaginal delivery with an Apgar score of 10'-10' and breast-fed, started babbling at the age of 9 months, learned to walk at the age of 13 months and was capable of combining a simple sentence at 20 months. She had no difficulties in recognizing simple words and communicating with peers. No special abnormality was detected in the family history on in the physical examination.

During the psychiatric interview, the girl expressed that she would talk about her thought rather in a familiar place than with a doctor in the consulting room. Her lack of persistent attention and frequent distraction were all normal characteristics of preschool children. Additional examinations showed that she had normal fontanelle closure, tooth development and vaccine inoculations according to the records of Shanghai Community Health Service Center. We also compared her height and weight with peers in Shanghai at P30/ P20. Her blood routine, electrolytes and trace elements were tested, and electroencephalogram (EEG) and magnetic resonance imaging (MRI) were arranged. Mini International Neuropsychiatric Interview for children and adolescents (MINI Kid) was evaluated ^[8]. Except for separation anxiety disorder (SAD) identified by MINI Kid, none of the examinations showed positive findings. The patient was subsequently diagnosed by psychiatrist to have somnambulism associated with SAD according to typical clinical symptoms.

At the beginning of the psychoanalytic therapy, the girl was asked to play a game with a new friend (a psychotherapist in our team), aiming to establish trust. She agreed to play but required the presence of her parents, otherwise she would cry at the first sight of the psychotherapist. SAD or other related symptoms were observed carefully as a possible incentive. In the second session, the psychoanalytic-oriented therapy aimed to collect information through a pre-designed game in which the psychotherapist acted as a judge and the child acted as a plaintiff, who was free to complain about any events in her life and about anyone including her family members, teachers and classmates. During the game the girl related a recent incidence around a week ago, in which her mother tried repeatedly to correct a mistake in her use of a knowing word but failed, and subsequently lost her patience and left her alone. This incident frustrated her for some time with the feeling of anxiety, and after that she had the scare that a similar scenario could happen again, which pointed to the trauma she experienced for the first time. Considering the psychological impact of the wrongful treatment by her mother she might unconsciously felt, which could be projected into sleepwalking, we aimed to reinforce a therapeutic alliance in the third-time session. During the interview, the game continued and the judge announced in court that her mother was wrong in the incident. The girl was very pleased with the verdict and the therapist played her mother's role to apologize for leaving her alone. The therapeutic sessions, from the first to the last interviews, lasted 4 days and the girl's symptoms improved obviously. After the therapy, she crept around bedside only once throughout the night without crying or sweating arousal. We arranged two further interviews to reinforce the therapeutic effect, and the sleepwalking symptoms disappeared entirely within a week. The girl did not expressed fears of strangers in the follow-up telephone interview 3 months later.

Benzodiazepines and antidepressants are commonly prescribed for therapy of somnambulism in adults and not recommended for children ^{[9, 10]}. Psychotherapy is recognized as a treatment option for both sleepwalking^[3] and SAD^[11]in children after they have the concept of ego at the age of 3 years. Psychological factors may trigger episodes of sleepwalking but they vary in individual cases, in which the psychological conflicts needed to be addressed. The case we present herein strongly suggests that family interaction problems and environmental factors all potentially contribute to sleepwalking in children.

Psychoanalysis has a unique therapeutic effect on anxiety disorder in adults, but it is seldom used in young children. Most patients who sleepwalk do not require treatment, but sleep disorders that result in daytime tiredness and behavioral and emotional problems require assessment and interventions^[12]. In our case, psychoanalytic therapy achieved a positive effect in the girl with sleepwalking and anxiety symptoms, suggesting its value as a feasible therapeutic option in children. The rationale of psychoanalysis is that the conscious activities control the unconscious activities, and desires that are not satisfied in daytime become disguised thoughts in latent dreams, which may destroy the frame of the dream by erupting into consciousness^[13]. Sleepwalking is such an episode that appears to turn the consciousness in NREM stage into unconsciousness in the REM stage^[1].

Sigmund Freud's The Interpretation of Dreams marked significant developments in the psychoanalytic understanding of the function and process of dream^[14]. Ego defense mechanisms were defined as unconscious resources used by the ego to decrease the conflict between the id and the superego^[15]. In this case, the id of the patient imaged her own desire by free association and took disguise in sleepwalking episode when the judge in the game formed a new conscience, while social norm, which represented the supergo that, by erupting into consciousness, destroyed the frame of the mother's authority, and the conflict vanished with the well-designed disguise by the psychotherapist.

It is easier to establish trust with children and cope with their resistance than with adults, and psychotherapy can thus be more effective^[16]. Sleepwalking represents the compromise between id and superego and reveals an obvious meaning of a dream that a psychotherapist should try to understand. The children's dreams are often difficult to interpret, but clues can be found in the details in the descriptions by family members. Id fades with age while ego and superego begin to develop in early childhood; the defense mechanism also increases from adolescence to middle age, and remains stable until late midlife^[17]. Early intervention of sleepwalking in childhood, through psychological therapy rather than medications, can decrease the false revival of unconscious desires that should be repressed in the future life.

Acknowledgement

We thank Prof. ZHU Min for proofreading the manuscript.