Cholesterol and Mental Health: A Balanced Perspective.

Sir,

Pereira[1] described a systematic review that examined the importance of cholesterol in psychopathology. The methods section of the paper listed the search terms but not the search date and the search strategy; in fact, the review lacked most of the characteristics that make a systematic review Preferred Reporting Items for Systematic Reviews and Meta-analyses compliant.[2] The single most important limitation of the review is that the findings of the identified studies were merely listed in a table. There was no critical evaluation of the literature, synthesis of findings, or discussion of the findings. There was neither take-home message nor new learning from the review. As a side comment, the review examined only studies published from January 2010 onward with no justification provided for the cutoff date. This is important because, when evaluating a field, there should be a good reason for excluding a substantial body of evidence that is relevant to the field.

A quarter of a century ago, a meta-analysis of six primary prevention randomized controlled trials (RCTs) suggested that lowering serum cholesterol levels was associated with an increased risk of mortality related to accidents, suicide, or violence;[3] a decade later, a meta-analysis of 19 RCTs showed that deaths due to these causes were not increased in patients treated with statins for either primary prevention or secondary prevention.[4] Subsequent studies were also reassuring.[5] In fact, meta-analysis of epidemiological as well as RCT data suggests that there is a lower risk of depression in statin users, and that statin augmentation of selective serotonin reuptake inhibitors has an antidepressant effect.[67] Against this is the finding from a meta-analysis of epidemiological data that lower serum cholesterol levels are associated with a higher risk of suicide attempt and completion.[8] We believe, as should all scientists, that RCT data comprise a superior quality of evidence and that the findings of the RCT meta-analyses[47] should therefore receive more weightage than the findings of the epidemiological data meta-analysis.[8]

Finally, and most important of all, it is important to reduce serum cholesterol in patients with major mental illness if only because such patients are at an increased risk of metabolic syndrome; statin treatment in such patients could, in the long run, significantly reduce medical morbidity and mortality, much as it does in the general population. The risk–benefit ratio clearly favors the reduction of serum cholesterol through statin treatment.[59]

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Conflicts of interest

There are no conflicts of interest.