All Norwegian psychiatric and addiction services are public and available to everyone. Most patients with mental or addiction problems are referred to the psychiatric department of the local hospital for their catchment area. Patients referred to other hospitals or institutions will be identified through close contact with these hospitals, institutions, general practitioners (GPs), and social services. In this way, it will be possible to identify and include most of the patients from a single catchment area who meet the study criteria. By selecting a sample of first-time-admitted patients, we will avoid the overrepresentation of chronically ill patients. We will use robust and validated diagnostic and psychometric instruments. The main diagnostic interview will be undertaken to differentiate between substance-independent and substance-induced disorders. The interviewer will choose the time and place of the appointments, and if necessary will provide transport to ensure that the patients are able to complete the interviews. This will limit the number of dropouts. The Norwegian Data Inspectorate has permitted some basic (unidentifiable) data to be collected from those patients who refuse to participate in the study, to assess whether the sample is representative. The interviewer has taken part in PRISM training and interrater reliability training for the different assessment and rating scales. All the PRISM and SCID-II interviews will be performed by the same psychiatrist, so interrater reliability problems should be avoided. Some of the PRISM and SCID-II interviews will be videotaped (with the patients' written consent) and scored blindly by another qualified rater.
Some of the patients will be users of psychoactive substances during the period of the interviews, so there will not be a four-week period of abstinence before the assessments. This may weaken the reliability of the information given by these patients. The study does not have a system for identifying all substance users in the catchment area. There will be some uncertainty about whether the treatment seekers are representative of the whole population. The sample size may be too small for the comparison of subgroups.
All patients with SUDs, admitted for the first time as inpatients or outpatients for psychiatric or addiction treatment, from a single catchment area during a specific time period, will be studied and diagnosed for substance use, and axis I and axis II comorbidity. As far as we know, this has not been done previously. At first-time admission, the first symptoms to occur and the disorder itself can be assessed more reliably than in later life, when this information must be reconstructed from memory. Therefore, this sample will make it possible to differentiate more accurately between independent and substance-induced disorders. Consequently, this study will better describe the prevalence of dual disorders than have most previous studies.
This study will be one of the first Norwegian studies to use the PRISM interview. A Norwegian version of this interview has recently been authorized. The interview is designed to diagnose comorbid substance-related and mental disorders. It is very important to acquire experience with the different recommended instruments within this field of clinical research.
For some decades now, attention has been directed to the complicated issue of diagnostic problems in patients with multiple disorders. It is extremely important to identify any independent psychiatric comorbidity in SUD patients and any comorbid SUDs in patients with mental disorders. Comorbidity seems to be the rule more often than the exception. In planning treatment, the following must be considered: the severity of the condition; whether the disorders are induced or independent; whether they should be treated separately, sequentially, or integrated; and where to find qualified treatment. An adequate diagnosis is necessary for this process. This study may show that the chosen assessment instruments are suitable. However, the interviews used in this study are time-consuming. It is probably not possible to perform this kind of diagnostic work in a time-efficient way.
Because the prevalence of these disorders varies widely between studies, it will be interesting to make a thorough diagnostic assessment of all first-time-admitted patients in a single catchment area, using a diagnostic interview which is proven to be reliable in dual disorder patients. More valid estimates of the prevalence of comorbidity in treatment seekers can then be presented. The catchment area based concept makes it possible to study a complete naturalistic sample, while most of the earlier studies have chosen convenience samples. This study of first time treatment seekers will avoid the problem of over representation of the most severely ill patients, and the retrospectively recalled symptoms will be less influenced by time lag and the effect of disease periods.
The duration of untreated SUD will be calculated. If the study shows that the duration of untreated SUD is long, e.g. several years, this will call for attention and better strategies for identifying SUD at an earlier stage. In many treatment settings for substance users, the skills in assessment and treatment of non substance mental disorders are limited. This is unproblematic if we find that most first time treatment seekers are mentally healthy except for their SUD, or if their mental disorders to a large extent are substance induced. If, however, this study reveals that most treatment seekers have comorbid disorders that demand specialized psychiatric treatment, today's treatment settings are insufficient. The division of patients with SUDs and psychiatric disorders into separate treatment clinics is based on tradition and not on professional consensus. This study may reveal new information that justifies either separate or combined services.
This project is approved by the Regional Committee for Medical Research Ethics (registration number 6.2008.100), and by the Norwegian Data Inspectorate. The BRAIN study, including the biobank, has the necessary approvals. The project will be carried out according to the Declarations of Helsinki and Madrid.
None of the procedures used in this study presents any risk to the patients' health. All screening instruments and interviews are internationally acknowledged and validated. All of them have been used in previous studies in other projects worldwide.
Our common experience is that patients are not averse to being thoroughly examined and that they usually do not find the examinations too strenuous. All patients will be given oral and written information about the study before they give their written consent. If a patient refuses to take part in any of the assessments, this will be respected. If the patient refuses most of the interviews, it will be understood that he/she does not want to participate in the study. To test for bias, it will be necessary to record some basic, unidentifiable data about the patients who refuse to participate in the study; e.g., age, sex, and type of substances used.
It is possible that the biomedical or other examinations reveal information that makes the provision of adequate care necessary to avoid compromising the patient's health. With the patient's consent, such information will be passed on to the patient's therapist or GP. In some situations, the patients might not wish to inform their therapists or GPs. In such cases, the patients' wishes will be respected. If life-threatening depression, psychosis, or intoxication is identified, the patient will be referred for adequate treatment.
Patients between the ages of 16 and 18 years are considered able to give their full consent regarding their participation in a study of this kind. If the research fellow encounters problems that require treatment for which a young patient cannot give his/her consent, or the parents must be informed to exercise their parental responsibility, the patient's therapist or GP will be informed.
All patients of 18 years or older will be asked to agree to videotaped recordings of the interviews. Refusal will have no consequences for the patient. If the patient accepts, he/she will sign a separate statement of agreement. The purpose of the recording, the use of the videos, their safekeeping, and erasure will be described.
The patients will also be asked for their permission for the research fellow to contact them within 10 years to ask them to participate in a follow-up study. To take part in the follow-up study, they will sign a new written consent at the time of the follow-up. Refusal of this permission will have no consequences for the patient.