Xingqi Daozhi Decoction for Antipsychotic-Induced Constipation

Antipsychotic-induced constipation is a common and clinically important adverse effect in patients receiving antipsychotic treatment. Anticholinergic and other pharmacological effects of antipsychotic medications may reduce gastrointestinal motility and intestinal secretion, leading to difficulty with defecation, abdominal distension, and other gastrointestinal symptoms. In severe cases, constipation may progress to serious gastrointestinal complications and may also negatively affect quality of life and adherence to psychiatric treatment.

From the perspective of traditional Chinese medicine, constipation with a qi stagnation pattern is characterized by difficult defecation accompanied by symptoms such as abdominal distension, belching, frequent passage of gas, and a sensation of incomplete evacuation. Treatment is directed toward regulating qi, relieving stagnation, and promoting bowel movements. Previous clinical observations of Xingqi Daozhi Decoction in constipation with a qi stagnation pattern suggested potential therapeutic benefit and acceptable tolerability, providing the rationale for further evaluation in patients with antipsychotic-induced constipation.

This exploratory study is designed to evaluate whether Xingqi Daozhi Decoction can improve constipation associated with antipsychotic treatment while maintaining acceptable safety and tolerability. Participants will undergo standardized clinical assessments throughout the treatment period, including evaluation of bowel habits, constipation-related symptoms, quality of life, psychiatric symptoms, treatment-emergent adverse effects, and routine safety parameters. Rescue treatment with glycerin enema may be used under predefined conditions when participants have no bowel movement for more than 3 consecutive days accompanied by abdominal discomfort, and its use will be recorded in the study documentation.

In addition to clinical efficacy and safety assessments, stool samples will be collected at selected time points for exploratory analyses of gut microbial composition and metabolites, including 16S rRNA sequencing and short-chain fatty acid measurements. These exploratory analyses are intended to investigate possible biological changes associated with treatment and to provide preliminary evidence regarding potential mechanisms of action.

After completion of the 8-week treatment period, participants may voluntarily enter an extended follow-up period of up to 1 year for continued clinical symptom assessment and telephone consultation.

Inclusion criteria

Meets the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria for schizophrenia.

Positive and Negative Syndrome Scale (PANSS) total score ≤95, with a PANSS negative symptom subscale score ≤28.

Meets the Rome IV diagnostic criteria for functional constipation with a qi stagnation pattern.

Aged 18 to 65 years. Has at least a junior high school education and is able to complete self-report questionnaires.

Has not used other medications known to cause constipation within the past 3 months.

Has had no history of constipation within the past 2 years and no previous gastrointestinal disease.

Developed constipation after initiation of antipsychotic medication.

Exclusion criteria

Meets DSM-5 diagnostic criteria for any psychiatric disorder other than schizophrenia.

Is unable to maintain a normal diet because of psychiatric symptoms, or requires a special diet such as a diabetic diet, soft diet, liquid diet, fasting, or restriction of oral intake due to individual clinical circumstances.

Uses other medications that may cause or aggravate constipation. Has had constipation within the past 2 years or has a history of gastrointestinal disease.

Has lactose intolerance. Has clinically significant medical conditions, including diabetes mellitus, hypothyroidism, connective tissue disease, or other significant physical illnesses.

Is pregnant, planning pregnancy in the near future, or breastfeeding.