Case: A 12-year-old primary school student was first admitted to a psychiatric hospital in October 2012 with the main cause of “alternating episodes of depression, sleepiness and talkativeness for 5 months”, family history unknown, previous allergy to cephalosporin antibiotics, introverted and docile personality before the disease. Current history: The patient started in May 2012, manifested as dozing in class, talking less, moody, often dropping tears, unable to persist in school, local diagnosis is unknown, given sertraline 50mg/day, transcranial magnetic stimulation treatment for more than 10 days, mood significantly improved, performance than before the onset of obvious talkative, extremely lively, not accompanied by excitement, irritability, reckless spending, impulsive behavior, etc.. In August 2012, he was diagnosed with “bipolar disorder” in a hospital and was treated with magnesium valproate, sertraline, and suxith (exact dosage unknown), but the improvement was not obvious. Before this admission, he had alternating episodes of excessive sleeping, reduced eating and activity for 1 week and normal sleeping and eating, lively and talkative for 1 week. Mental status examination on the day of this admission: clear, complete orientation, good passive contact, and tangential questions and answers. The volume and speed of speech were acceptable, and the organization was clear. No hallucinations, delusions and other psychotic symptoms were detected. He could clearly tell that he got sick at the end of May, “one week is good, one week is bad”, and when it is bad, he “sleeps a lot, always commits crimes, has terrible nightmares, doesn’t want to get up, doesn’t want to eat”, and admits that when his mood is the worst, he “just doesn’t want to live in this world anymore”. When it is good, “I don’t commit any more, I am more lively and talk more than usual”. Good self-awareness, shy expression, acknowledges previous low mood and more pleasant experiences, and is satisfied with his or her current state. Active treatment seeking, well behaved, quickly became friends with other patients in the ward and played together. Disease diagnosis and differential: depressive state, bipolar disorder; differential diagnosis: episodic sleep disorder, recurrent depressive disorder, mood disorder specific to childhood. Admission treatment history: Week 1: tapered off sertraline, magnesium valproate extended-release tablets 750 mg/day, and suxamethonium replaced with Seroquel 100 mg/day. Week 2: On the 9th day of admission, the patient took the initiative to contact the doctor and was happy to see him, complaining that he was “in a good mood” and thought that he was in a similar state to his usual state, and that he was “not well” since yesterday. When asked about the patient’s experience last week, he mostly complained that he “did not remember” and admitted that he only wanted to sleep, did not want to move and had no appetite. They denied that they had more energy, quick thinking, more ideas, more plans, etc. The patient has a happy expression and considers his or her mood to be similar to normal. He can actively interact with his patients and go downstairs together, showing liveliness and good self-care, and is satisfied with his current state, and does not see irritability or excessive activity. Week 3: On the 17th day of admission, he was sleeping in bed, ignoring repeated calls to his name, nudging the patient, frowning and not wanting to be disturbed, refusing to talk, and sleeping with his head covered. After waking up, he was depressed, and he was reluctant to talk. The test of nail function: TSH 8.36uIU/ml, FT4 0.53ng/dl, TT4 3.92ug/dl, considering the existence of subclinical hypothyroidism. Week 4: started combined lithium carbonate treatment, gradually increased the dosage to 0.75g/day; on the 26th day of admission, good passive contact, question and answer cooperation, and could carefully recall last week’s experience. He thinks his illness is “sleeping a lot, sleeping for a week, getting up several times when sleeping a lot, dreaming, unpleasant dreams”, admitting that when sleeping a lot, “there is something to do, but I don’t want to do it, I’m not interested in doing it”, admitting that at that time “I can’t describe it, but I was particularly annoyed, sometimes I wanted to cry, there was no hope, I felt especially useless, I wouldn’t get better, and people around me couldn’t help me”. Admitted that now the mood is a little better than usual, “because I woke up from the dream, I feel especially happy. Denies having more energy and less sleep. Able to do crafts and self-study textbooks with patients. Weeks 5-7: Magnesium valproate extended-release tablets 750mg/day, Seroquel 300mg/day, lithium carbonate 0.75g/day. The child was well behaved and polite, with moderate speech volume and speed, and clear speech organization. He denied the experience of high and low emotion. He was well behaved in the ward and interacted well with his patients. The child’s blood lithium was 0.73 mmol/L. The child’s nail function was 6.69 uIU/ml, FT4 0.48 ng/dl, TT4 4.52 ug/dl, and subclinical hypothyroidism was in remission. Outpatient follow-up: no further depressive and manic episodes. He was somewhat sullen most of the time, lacked initiative in learning, and no longer served as class president. Maintenance treatment: magnesium valproate extended-release tablets 750mg/day, Seroquel 300mg/day, lithium carbonate 0.75g/day.