Research projects

Screening for Co-Morbid Affective Disorder and Substance Abuse Disorder by General Practitioners

Principal Researchers

Ms Sandra Davidson¹, Dr Benny Monheit², A/Prof. Peter Schattner² and Ms Stella Koritsas²:

Institution

¹ Department of General Practice, University of Melbourne

² Department of General Practice, Monash University

Funding

$50,000

Award Type

beyondblue Victorian Centre of Excellence

Project completion year

2006

Project brief

The co-occurrence of symptoms of depression and substance abuse is associated with greater functional impairment and poorer prognosis than is generally seen among people with a single diagnosis. Low treatment rates, increased relapse, re-hospitalisation and violence are all reported among people with co-morbid depression and substance abuse disorder. However, US research suggests that general practitioners (GPs) frequently fail to detect substance abuse disorder among people diagnosed with depression (Mallin, Slott, Tumblin & Hunter, 2002).

This study aimed to determine how frequently GPs screen for alcohol and illicit drug use among patients diagnosed with depression and to estimate the number of co-morbid cases missed.

The research was based on a clinical audit design, where GPs completed an initial retrospective audit of 20 patients diagnosed with depression in the previous two years. GPs were asked to indicate whether they had discussed alcohol and drug use with each patient, and to indicate what they believed was the alcohol and illicit drug intake for that patient. GPs mailed questionnaires to the audited patients.  These questionnaires asked the patients to indicate a range of lifestyle behaviours, including drug and alcohol use, at the time of their depression diagnosis. Patients returned these questionnaires directly to the researchers. GP and patient questionnaires were matched to estimate the difference between patient reported alcohol and drug use and GP’s knowledge of the patient’s alcohol and drug use. The 47 GPs who participated in the study collectively audited 869 patient records, 517 of whom returned questionnaires to the researchers.

Key Findings

This study found a significant discrepancy between reported levels of substance use by depressed patients and GP knowledge of patient’s substance use.

In regard to alcohol, a significant proportion of patients diagnosed with depression consumed alcohol at levels that may contribute to their depressive symptoms, yet their GP was unaware of such behaviour. Overall, 12% of male patients and 23% of female patients reported potential alcohol misuse. GPs indicated potential alcohol misuse for only 4% of males and 7% of females. Similarly, 11% of males and 18% of females reported probable alcohol misuse while GPs indicated potential misuse for 3% and 6% respectively.

The discrepancy between patient-reported illicit drug use and GP knowledge of patient’s drug use was much less than it was for alcohol. It also occurred in the opposite direction, with GPs being more likely to suspect probable drug abuse than patients were to report it. However, this must be interpreted in light of the social and legal repercussions of illicit drug taking, which may have caused patents to under-report their drug use.

GPs’ screening patterns varied significantly according to demographic factors. Male patients were screened for alcohol consumption 1.3 times more frequently than female patients and patients aged between 30 and 59 years were most likely to be screened.

Implications for Policy and Practice

The high rate of possible alcohol disorder and depression co-morbidity suggested by these results, combined with the high rate of missed cases, indicates a pressing need for further research in this area.

At present, it appears that many patients with depression are drinking alcohol at levels which may contribute negatively to their mood state, yet this is not being recognised by their GP.

GPs who participated in this study put forward some excellent suggestions to enhance the detection of substance abuse among patients with depression. These suggestions have been incorporated into the following recommendations:

  • Include substance-use screening in initial, routine history taking
  • Make longer appointment times to assess lifestyle issues that can exacerbate and complicate depression
  • Do not make assumptions about patient’s substance use based on demographic factors
  • Understand the treatment needs of people suffering from co-morbid mood and substance-use problems
  • Provide patients with information on the interaction between depression and substance use.

About the Researcher

Sandra Davidson began her PhD in the Department of General Practice in May 2006 under the supervision of A/Prof Jane Gunn and Professor Chris Dowrick (University of Liverpool).   She is investigating the relationship between social ties and health care utilisation among people with depression. In particular, she is examining whether depression care among people who are socially isolated is more likely to be characterised by lack of continuity compared to people who have stronger social ties.

References

Mallin, R., Slott, K., Tumblin, M., & Hunter, M. (2002). Detection of substance use disorders of patients presenting with depression. Substance Abuse, 23, 115-120.