Suicide is not a mental illness. It is a behavior with complex, varied causes that can include mental illness but is not limited to it. The American Psychiatric Association considered adding “Suicidal Behavior Disorder” as a formal diagnosis in the DSM-5 but ultimately rejected it, concluding that suicidal behavior does not meet the criteria for a mental disorder because it is a behavior with diverse causes rather than a distinct condition. About half of all people who die by suicide do not have a known diagnosed mental health condition at the time of death.
Why Suicide Is Not Classified as a Diagnosis
When the American Psychiatric Association updated its diagnostic manual (the DSM-5), a panel of experts proposed listing suicidal behavior as its own disorder. The proposed criteria defined it as a suicide attempt within the past 24 months, specifically an act the person initiated with the expectation that it would end their life. The proposal excluded acts motivated solely by political or religious objectives, acts done during delirium, and self-injury done to relieve emotional pain without intent to die.
After review, the proposal was dropped. The rationale: suicidal behavior has too many different causes to qualify as a single mental disorder. Instead, it was placed in a catch-all category called “Other Conditions That May Be a Focus of Clinical Attention,” alongside things like relationship problems, housing instability, and bereavement. In other words, the psychiatric field formally recognizes suicidal behavior as something clinicians should assess and address, but not as a standalone illness.
The Link Between Mental Illness and Suicide
Depression, alcohol use disorders, and a history of previous suicide attempts are well-established risk factors, particularly in high-income countries. There is also a biological dimension. About 30 years of research has documented abnormalities in the brain’s serotonin system among people who die by suicide, including changes in receptor activity in the prefrontal cortex. Family, twin, and adoption studies show that vulnerability to suicidal behavior is partly heritable, and that this heritability is partially independent of the transmission of psychiatric disorders themselves. The body’s stress-response system also plays a role: impaired functioning of the hormonal stress pathway may contribute to risk during acute crises.
But the relationship is not as simple as “mental illness causes suicide.” The World Health Organization notes that many suicides happen impulsively during moments of crisis, triggered by a breakdown in the ability to cope with life stresses like financial problems, relationship disputes, or chronic pain. The CDC estimates that roughly half of people who die by suicide had no known mental health diagnosis. Mental illness raises risk significantly, but it is neither necessary nor sufficient to explain why someone takes their life.
Non-Psychiatric Factors That Drive Suicide Risk
The CDC identifies risk factors across four levels: individual, relationship, community, and societal. Many of these have nothing to do with a psychiatric diagnosis.
- Individual factors: chronic pain, serious physical illness, criminal or legal problems, job loss or financial hardship, a history of childhood adversity, and experience with violence.
- Relationship factors: social isolation, loss of important relationships, high-conflict or violent relationships, and bullying.
- Community factors: lack of access to healthcare, exposure to a suicide cluster, community violence, historical trauma, and discrimination.
- Societal factors: stigma around seeking help, easy access to lethal means, and irresponsible media portrayals of suicide.
People who have experienced violence, including child abuse, sexual violence, or bullying, face elevated risk regardless of whether they carry a psychiatric diagnosis. In low- and middle-income countries, where 73% of the world’s suicides occur, limited access to mental healthcare means that social and economic stressors play an outsized role.
How Experts Think About the Path to Suicide
One influential framework, the Interpersonal Theory of Suicide developed by psychologist Thomas Joiner, identifies four key ingredients. The first is thwarted belongingness: the feeling of being disconnected from others. The second is perceived burdensomeness: the belief that your existence is a burden on the people around you. The third is hopelessness that those two states will ever improve. Together, these three factors produce the desire to die. The fourth ingredient, capability for suicide, is what bridges the gap between wanting to die and acting on it. People who have been exposed to pain, violence, or prior self-harm may develop a diminished fear of death that makes an attempt more likely.
This model helps explain why suicide is not simply a symptom of depression or any other single illness. A person can experience thwarted belonging after a divorce, perceived burdensomeness after losing a job, and hopelessness during a financial crisis, all without having a diagnosable mental health condition.
Why the Distinction Matters
Framing suicide solely as a product of mental illness can create blind spots. If clinicians, policymakers, and families assume that only people with psychiatric diagnoses are at risk, those experiencing financial ruin, chronic pain, social isolation, or relationship crises may go unrecognized until it is too late. The WHO classifies suicide as a public health problem requiring a public health response, not just a clinical one. Reducing the global suicide rate is, in fact, the only mental health indicator included in the United Nations Sustainable Development Goals.
Language has shifted to reflect this broader understanding. Major organizations, including the American Psychiatric Association, now advocate for person-first, non-judgmental phrasing. “Committed suicide,” with its echoes of crime and sin, has given way to “died by suicide.” Labels like “successful” or “unsuccessful” attempts have been replaced by “suicide attempt” and “death by suicide.” Since 2015, the preferred framing has been “person living with thoughts of suicide,” recognizing suicidal thinking as a treatable experience rather than a defining identity.
In 2021, an estimated 727,000 people worldwide died by suicide, accounting for 1 in every 100 deaths globally. Among people aged 15 to 29, it was the third leading cause of death overall and the second leading cause among young women. These numbers reflect a problem that cuts across diagnostic categories, economic classes, and cultures. Treating suicide as a behavior shaped by many forces, rather than a symptom of one illness, opens the door to prevention strategies that reach people wherever they are.