Setting and treatment procedure

This prospective observational study was conducted in a highly specialized psychiatric inpatient unit. The unit is registered for qualified detoxification treatment of substance use disorders within Jüdisches Krankenhaus Berlin. The team consists of medical doctors, psychologists, specialized nurses, occupational therapists, physiotherapists and social workers. The qualified detoxification treatment (QDT) combines physiological treatment with psychotherapy, psychoeducation and relapse prevention. It is a three-step process. During detoxification the patients physically withdraw from the drug and, when needed, withdrawal symptoms are treated pharmacologically. In a second step, the patients attend a minimum of five psychotherapeutic group sessions and two psychoeducational group sessions. The third step prepares the patients for the transition to long-term follow-up treatment after discharge and includes attendance of five self-help groups in an outpatient setting. The average duration of treatment overall is between 12 and 16 days but may be significantly longer if withdrawal symptoms persist, as is often the case with GHB detoxification, or if the patient is in poor physical health. Patients seeking withdrawal treatment are screened in our outpatient department prior to admission. A physical examination is performed and the medical history is taken. The patients give consent to the treatment procedures in hospital.

The study was approved by the local ethical committee of Charité—Universitätsmedizin Berlin (reference number: EA1/235/21).

Patients

Between March 2019 and September 2020 all patients who were admitted for a GHB-dependency were screened for study participation by the medical doctors responsible for the treatment and asked for participation. No incentives were offered. Data was collected prospectively by the study doctors (PN and FE). Due to the coronavirus pandemic the study was interrupted between March and June 2020 and resumed on 1st July 2020.

Inclusion and exclusion criteria

Inclusion criteria were (1) Fulfilling criteria for GHB substance use disorder, (2) Patients agreed to an elective admission for detoxification treatment, (3) They had sufficient proficiency in the German language and (4) They had capacity to give informed consent. Exclusion criteria were (1) A diagnosis of substance use disorder of any sedative other than GHB, (2) Lack of capacity and insufficient command of German language. All patients gave written informed consent.

Diagnostic criteria

We used DSM-V criteria [20] for diagnosis of substance use disorder and withdrawal criteria focusing on delirium, seizures and concomitant illnesses evaluated by an experienced psychiatrist.

Treatment and participating staff

All patients received treatment as usual (see treatment procedure and medication). The attending doctors or health professionals were not blinded with regards to the study.

Medication

All patients received medication as usual if eligible. Our GHB detoxification regime uses diazepam with an initial dose of 10–20 mg every 2 h according to physiological response. Assuming that the patients would take his or her last GHB right before entering the clinic, we started applying diazepam right after admission in order to reduce the risk of heavy withdrawal symptoms and delirium. Reduction started step by step under control of heart rate, blood pressure and symptoms of delirium.

For treatment of delirium we used benzodiazepines in combination with antipsychotics.

Definition of complications

Diagnoses of complications like delirium and seizures were made by an experienced psychiatrist. There were no standardized criteria for referral to intensive care. In GHB-patients referral to ICU was usually indicated if the dosage of diazepam was above 140 mg in 24 h. The decision was made by the responsible consultant psychiatrist and physician on-call.

Definition of successful treatment

Treatment was considered a success if a patient completed the program and remained abstinent until discharge. A break of the regular program by an admission to intensive care would be resumed after return to the regular ward.

The treatment was considered aborted if a patient was discharged against medical advice or was using substances and refusing to participate in the treatment program leading to a premature discharge.

Data analysis

To address the questions as described in the introduction, a descriptive analysis was carried out. Categorical variables were summarized by frequency and percentage tabulation regarding the following clusters:

1. Socioeconomic history (age, sex, status of graduation, occupation and employment, partnership, children, history of imprisonment). Status of school graduation was categorised in four groups: attending school for 9, 10 or 13 years, the latter giving you access to all university degrees in Germany. Students attending school for 8 years or less leave school without any qualifications. Post-school education was categorised in four groups with rising status: none, undertaking apprenticeship or currently in university education, apprenticeship successfully finished, university degree completed. Employment was categorised in six groups (see Table 1).

Table 1 Socioeconomic data of cases

2. Clinical history (additional addictive diseases, additional psychiatric or non-psychiatric diagnoses, first age at onset of any addictive disease, occurrence of previous detoxification treatments, occurrence of previous dropouts, previous withdrawal seizures, occurrence of previous delirium, previous referral to ICU during QDT story of use of psychotropic substances and psychiatric diseases, age of onset of dependency, number of previous detoxifications and history of complications during previous detoxification treatments) (see Table 2).

3. Clinical course (occurrence of delirium, withdrawal seizures, need for intensive care and artificial ventilation, premature drop-out of the treatment program and discharge against medical advice) as indicated in Table 3.

Table 3 Data of clinical course

All data was captured and evaluated by an experienced physician. Statistical analyses were carried out using SAS (statistical analysis system) software by SAS Institute. For bivariate comparisons Fisher’s exact test or a t-test were used.