CRD summary

This poorly reported review assessed suicidal risk reduction with long-term lithium maintenance. The authors' concluded that long-term maintenance with lithium is associated with major reductions in risks of suicides and attempts in bipolar I disorder and other recurrent major affective illnesses. The review has several methodological weaknesses. The results from included studies and their subsequent synthesis may not be reliable.

Authors' objectives

To update and extend analyses of published data pertaining to suicidal behaviour in patients treated with and without lithium therapy (see Other Publications of Related Interest nos.1-3).

Searching

MEDLINE (from 1970 to mid-2002) was searched using the keywords 'lithium' and 'suicide'. In addition, the bibliographies of recently published reports were reviewed.

Study selection

Assessment of study quality

The authors did not state that they assessed validity.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction. The rates (events/100 person-years) for each study were calculated.

Methods of synthesis

Results of the review

Thirty-four studies (n=16,221) with 67 treatment arms or conditions (42 with and 25 without lithium treatment) were included. Three of the studies were double-blind randomised controlled trials. The study design of the other 31 studies was not indicated.

Overall. The estimated rate for completed suicides was 0.174 (95% CI: 0.138, 0.215) with lithium treatment versus 0.942 (95% CI: 0.743, 1.180) without; the RR was 5.43 (95% CI: 3.57, 8.25); the reduction was 81.5%. The estimated rates for suicide attempts were 0.312 (95% CI: 0.204, 0.451) and 4.646 (95% CI: 4.104, 5.239) with and without lithium treatment, respectively; the RR was 14.9 (95% CI: 8.41, 26.4); the reduction was 93.3%. The estimated rates for all suicidal acts (completed suicides and suicide attempts) were 0.210 (95% CI: 0.172, 0.253) and 3.100 (95% CI: 2.803, 3.422) with and without lithium treatment, respectively; the RR was 14.8 (95% CI: 8.54, 25.6); the reduction was 93.2%.

Bipolar disorder. The estimated rate for all suicidal acts was 0.295 (95% CI: 0.216, 0.394) with lithium treatment versus 6.102 (95% CI: 5.320, 6.966) without; the RR was 20.7 (95% CI: 11.9, 35.8); the reduction was 95.2%.

Major affective disorder. The estimated rate for all suicidal acts was 0.193 (95% CI: 0.151, 0.244) with lithium treatment versus 2.119 (95% CI: 1.829, 2.441) without; the RR was 11.0 (95% CI: 5.37, 22.4); the reduction was 90.9%.

Further results of comparisons of suicide rates found with and without lithium to general population rates were also presented, as were secular trends in suicide rates and effects of lithium treatment.

Authors' conclusions

Long-term maintenance treatment with lithium salts is associated with major reductions in risks of suicides and attempts in bipolar I disorder and other recurrent major affective illnesses (bipolar II disorder and unipolar depressive) that mainly involve depression.

CRD commentary

The review question was clearly stated. However, a priori inclusion criteria relating to the study design were not specified and there was insufficient information about the design of the studies included. The search was restricted to one database, supplemented only by a review of reference lists of recent reports, and the review appears to have been limited to English language publications. Therefore, relevant studies may have been missed, and language and publication bias may be present. The validity of the included studies was not assessed. Hence, the results from these studies, and their subsequent synthesis, may not be reliable. There was no information on how the studies were assessed for inclusion or how the data were extracted from them. Thus, it is not possible to assess whether steps were taken to minimise error and bias in the review process. It is also unclear whether the statistical pooling of the studies was appropriate, as heterogeneity was not formally assessed. The most tentative interpretation of the authors' conclusions is advisable.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice. Research: The authors stated that it is important to include assessments of mortality risk and suicidal behaviour in long-term studies of the effectiveness of anticonvulsants and other alternatives to lithium to treat bipolar disorder. It should also be clarified whether modern antidepressants reduce suicidal risk in recurrent unipolar major depressive illnesses. In addition, further study into the potential adjunctive role of lithium, or other mood-stabilising agents, as a means of reducing the risk of suicide in recurrent unipolar depression is required.

Funding

GlaxoSmithKline.

Bibliographic details

Baldessarini R J, Tondo L, Hennen J. Lithium treatment and suicide risk in major affective disorders: update and new findings. Journal of Clinical Psychiatry 2003; 64(Supplement 5): 44-52. [PubMed: 12720484]

Other publications of related interest

1. Baldessarini RJ, Tondo L, Hennen J. Treating the suicidal patient with bi-polar disorder: reducing suicide risk with lithium. Ann N Y Acad Sci 2001;932:24-43.

2. Tondo l, Hennen J, Baldessarini RJ. Lower suicide risk with long-term lithium treatment in major affective illness: a meta-analysis. Acta Psychiatr Scand 2001;104:163-72.

3. Baldessarini RJ, Tondo L, Hennen J, Viguera AC. Is lithium still worth using? An update of selected recent research. Harv Rev Psychiatry 2002;10:59-75.

Baldessarini RJ, Tondo L, Davis P, Pompili M, Goodwin FK, Hennen J. Decreased risk of suicides and attempts during long-term lithium treatment: a meta-analytic review. Bipolar Disorders 2006; 8(5 Part 2): 625-639.

Indexing Status

Subject indexing assigned by NLM

MeSH

Bipolar Disorder /drug therapy /prevention & control /psychology; Depressive Disorder /prevention & control /psychology; Humans; Lithium /therapeutic use; Mood Disorders /drug therapy /prevention & control /psychology; Risk Factors; Suicide /prevention & control /statistics & numerical data; Suicide, Attempted /prevention & control /statistics & numerical data

AccessionNumber

12003001082

Database entry date

30/11/2004

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.