Who leaves a suicide note? A systematic review of differences between note writers and non-note writers

Suicide notes represent one of the few first-person sources of information on the suicidal process. However, only a minority of individuals who die by suicide leave a note, raising the question of whether note writers (NW) are representative of the broader population of suicide decedents. This systematic review aimed to synthesize the available evidence on differences between NW and non-note writers (NNW) across sociodemographic, clinical, psychosocial, and suicide-related variables. A systematic search was conducted in PubMed and ProQuest databases up to June 22, 2026, following PRISMA guidelines. Studies were included if they compared NW and NNW on at least one variable, or investigated predictors of note-leaving. Thirty-three studies met the inclusion criteria. Evidence was heterogeneous and suggested that NW cannot be clearly distinguished from NNW based on sociodemographic and clinical variables. Concerning suicide-related variables, the method of suicide was the most consistently different between NW and NNW; in particular, the most frequent methods of suicide in NW, compared to NNW, were non-violent methods like poisoning/overdose and gas inhalation. Rather than solely reflecting a distinct psychological profile, suicide note-leaving may also be influenced by the circumstances surrounding the suicidal act. One possible, although untested, explanation is that leaving a note requires a degree of cognitive and emotional organization that may be less compatible with highly disorganized or impulsive suicidal states.