Improving Care for Patients with Dual Disorders: Depression and co-occurring alcohol use

When substance use and other mental disorders co-occur in the same patient, this is referred to as a dual disorder or dual diagnosis. The more severe the psychiatric illness, the more common the substance use disorder. For example, around 40% of people with depression also have an alcohol use disorder at some point. Depression is a global public health problem and the harm it causes is significant at both individual and societal levels. Similarly, substance use disorders, in particular alcohol use, are common. Consequently, co-occurring disorders are also very common but insufficiently diagnosed and treated.

There is a wealth of evidence on biological and psychosocial treatments for depression. Medications are widely used and psychotherapy should also be part of the treatment. Alongside long-term psychotherapy, evidence-based brief therapies can provide adequate help. A number of evidence-based treatments are also available for problematic alcohol use. However, treatment pathways and methods for dual disorders vary widely and research evidence to support treatment decisions is still relatively scarce.

It is important to study the effectiveness of various interventions in real-life patients, in a naturalistic setting where patients are symptomatically heterogeneous. The South Ostrobothnia Hospital District's development project, including the Ostrobothnia Depression Study, was carried out between 2009 and 2013. The aim was to improve the systematic assessment of patients presenting for treatment for depressive symptoms and promote the use of evidence-based brief treatment interventions. The treatment intervention consisted of a systematic initial assessment including substance use screening, motivational interviewing for those who had substance use and treatment of depression with behavioural activation, an application of cognitive-behavioural therapy.

This dissertation examines the treatment and prognosis of dual disorder patients in psychiatric care, with a particular focus on depression and co-occurring alcohol use. The first substudy examines patients (n=330) in psychiatric care with varying psychiatric illnesses, but all with a common factor of reported substance use in the previous year. In the other substudies, the study data are patients from the Ostrobothnian Depression Study (n=242). These patients were treated primarily for depressive symptoms, but the majority also had other psychiatric disorders or heavy alcohol use. The results of the treatment intervention will be examined in particular from the perspective of patients' functioning and quality of life, taking into account the impact of co-occurring alcohol use on treatment success.

The results of the first substudy showed that in the group of dual disorder patients receiving standard psychiatric care, functioning remained stable at follow- up. Diagnosed substance use disorders were associated with frequency of treatment and prescribed drug doses in this data set. In the other substudies, the outcomes of patients treated with behavioural activation were examined. It was found that patients' depressive symptoms decreased, functioning and quality of life improved, and heavy drinkers' alcohol consumption decreased. Patients' functional capacity improved more than that of the patients in the control group, who received conventional treatment. Patients' health-related quality of life improved regardless of whether they had co-occurring alcohol use. Female gender, lower alcohol consumption and the absence of an anxiety disorder seemed to be predictive of improved quality of life. Good treatment response for depression during the intervention was predicted by more severe depression at baseline and higher alcohol consumption before treatment.

In psychiatric care, more attention should be paid to the systematic screening and treatment of substance use disorders. The systematic use of brief therapeutic interventions for depression should be increased and the knowledge of these methods strengthened. Behavioural activation combined with motivational interviewing, if necessary, seems to be an appropriate treatment option for psychiatric patients with depression and other psychiatric symptoms or alcohol use disorder. Depression should be actively treated, even if the patient has heavy alcohol use at the time of admission.