This is to our knowledge the first study to assess the suicide risk in people in the second half of life who discontinue treatment with antidepressants.
Both people who continued treatment and those who discontinued treatment early had 3–5 fold higher suicide rates than the general population of the same age range (own calculations; BEF1A, 2007
; FOD5, 2007
Men aged 50 years and over who followed treatment had a 2.3-fold higher suicide rate than women who followed treatment, while men who discontinued treatment had a 3.2 fold higher suicide rate than women over aged 50 in the same situation. In other words, men who discontinued treatment had disproportionally higher suicide rates than women. This could be related to women’s more frequent use of primary health care (Vedsted, 2007
) and men’s higher suicide risk in general (Erlangsen et al., 2003
People are prescribed antidepressants by their general practitioners for a wide range of disorders (Creed, 2006
; Giuliano, 2007
; Rahme et al., 2008
; Sindrup et al., 1992
). Previous psychiatric in-patients and current ambulatory care patients might be more likely to suffer from severe mood disorders. During a psychiatric hospitalization patients are likely to receive a clinical evaluation for depressive symptoms. People with moderate and severe major depression respond better to antidepressant treatment than those with less severe mood disorders (Blazer, 2003
). Previous in-patients and current ambulatory care patients who discontinued treatment were found to have slightly higher risks of suicide compared to those who continued treatment. Although this finding was not statistically significant, it seems probable that this group might need the medication and be at higher risk of suicide when interrupting treatment. The survival curves in support this notion.
Individuals with previous psychiatric treatment had a higher risk of suicide than the rest of the study sample. Psychiatric hospitalization is likely to be an indicator of the severity of psychiatric disorder. The lack of specificity associated with risk factors and the low base rate generally hinders the prediction of suicides (Hawton, 1987
; Knox et al., 2004
; O’Connell et al., 2004
). However, general practitioners usually have information on previous hospitalizations and this could be used to intensify follow-up efforts during the initial period of treatment with antidepressants.
As many as 42% of adults over age 50 seemingly interrupted treatment after just one prescription. Discontinuation can be due to lack of medical effect of the drug (Beyer, 2007
) or side effects (Westenberg et al., 2006
). Nevertheless, evidence-based research suggest that treatment with a single antidepressant or combination of antidepressants, cognitive behavioral therapy, other types of psychotherapy, and electroconvulsive therapy can reduce depressive symptoms in older adults (Charney et al., 2003
; Steinman et al., 2007
). Improved adherence to antidepressant treatment has been shown by multimodal interventions focusing on collaborative care (Vergouwen et al., 2003
). Furthermore, involvement of case managers who follow and support the treatment course has been linked to lower suicidal ideation (Bruce et al., 2004
One limitation of our study is the indicator of treatment adherence. We do not know whether pills were actually ingested nor precisely when the treatment was discontinued. Although we controlled for a wide selection of covariates, it would have been preferable to have information on risk modifiers, such as severity of depression, previous suicide attempts, and current psychiatric disorders. Also, having more details regarding the reasons for ending treatment and length of intended treatment would have enabled us to evaluate our findings in more depth. In this regard it is important to acknowledge that, as mentioned above, antidepressants are prescribed for a variety of disorders in adults over age 50.
Underreporting of suicide might be a further limitation, but the registration of suicide in Denmark is generally thought to be reliable (Kolmos et al., 1987
). Our findings are not applicable to people who are currently receiving in-hospital treatment.
Advantages of the study include the prospective data collection and longitudinal setting using the entire population for selecting the study sample.
In conclusion, contrary to our expectation, we found no difference in risk of suicide among individuals over age 50 who discontinued treatment with antidepressants at a premature stage in comparison with those who followed treatment.