Sedatives and hypnotics are widely prescribed to older adults who have symptoms of depression, anxiety, and sleep disturbance. A recently published study conducted in Sweden aimed to determine whether different types of psychotropic drugs were associated with increased risk of suicide in persons aged 65 years and above after adjustment for appropriate indications (BMC Geriatrics 2009;9:20).

A case-controlled study of suicides was performed and close informants for 85 suicide cases (46 men, 39 women; mean age 75 years) were interviewed by a psychiatrist. A population-based comparison group (n = 153) was created and interviewed face-to-face. Primary care and psychiatric records were reviewed for suicide cases and comparison subjects. All information was used to determine past-month mental disorders in accordance with DSM-IV criteria. For study purposes, the authors classified the following drugs as sedatives: diazepam, alprazolam, buspirone, hydroxizine, and dixyrazine. They classified the following as hypnotics: flunitrazepam, nitrazepam, zopiclone, zolpidem, oxazepam, levomepromazine, propiomazine, and alimemazine.

Psychotropic drugs were found to have been widely prescribed to the suicide cases and all drug types were associated with suicide in the unadjusted analyses. Antidepressants were prescribed to 40% of the cases at the time of the suicide. Antidepressants, antipsychotics, sedatives, and hypnotics were associated with increased suicide risk in the crude analysis. After adjustment for affective and anxiety disorders neither antidepressants in general nor SSRIs showed an association with suicide. Antipsychotics had no association with suicide after adjustment for psychotic disorders. Sedative treatment was associated with an almost fourteen-fold increase of suicide risk in the crude analyses and remained an independent risk factor for suicide even after adjustment for any DSM-IV disorder. Having a current prescription for a hypnotic was associated with a four-fold increase in suicide risk in the adjusted model.

The authors reviewed possible explanation for the observed increase in suicide risk associated with sedatives and hypnotics in their study, including the possibility that these drugs trigger aggressive behaviour. They further noted that interactions between benzodiazepines and alcohol may intensify impulsive tendencies, thereby increasing risk of suicide. Some 29% of the suicide cases in the study had a positive postmortem test for alcohol.

The authors cautioned that their finding that sedatives and hypnotics were associated with increased suicide risk does not prove causality. They suggested that use of these drugs may be markers for some other factor related to suicide risk, such as somatic illness, functional disability, alcohol use disorder, interpersonal problems, lack of social network, and sleep disturbance.

Nonetheless, they concluded that sedatives and hypnotics were both associated with increased risk for suicide after adjustment for appropriate indications. They advised that, given high prescription rates for these agents, a careful evaluation of the suicide risk should always precede prescribing a sedative or hypnotic to an older patient.