Why can non-suicidal self-harm increase the risk of suicide?
Non-suicidal self-injury (NSI) refers to behaviors in which a person intentionally causes physical harm to themselves, but without the intent to die. This behavior can have various objectives, ranging from regulating a negative emotional state to gaining positive social attention from others or creating environmental changes. But does non-suicidal self-injury increase the risk of suicidal behavior?
Occasional non-suicidal self-harm does not necessarily imply an increased risk of suicide, but it does indicate the presence of emotional distress. Conversely, it is known that when self-harm becomes recurrent , frequently used, and eventually a habitual pattern, it becomes a risk factor that increases the likelihood of a suicide attempt and death by suicide. Hence the importance of early intervention when self-harm first appears in adolescence to prevent it from becoming chronic.
Risk and protective factors for self-harm
The relationship between recurrent non-suicidal self-injury and suicidal behavior
There is no single explanatory model for how recurrent non-suicidal self-injury increases the risk of suicide. The three explanatory models of this association that have the most support in the scientific literature are the following:
1. Gateway theory
This model posits that non-suicidal self-harm forms part of a continuum of severity. In other words, it is not an isolated phenomenon, but rather the tip of the iceberg of a process that can evolve into suicidal ideation , suicide attempts, and completed suicide. According to this model, this behavior indicates that the person is already experiencing significant emotional distress and is using maladaptive coping strategies.
If self-harm does not improve over time and distress increases, the strategies may escalate, and suicidal thoughts and behaviors may emerge. Thus, according to this model, non-suicidal self-harm is the first step on a continuum that can end in death by suicide.
2. Third Variable Theory
This model proposes that the relationship between non-suicidal self-injury and suicidal behavior is not direct, but rather that both are consequences of the same underlying risk factors, such as depression, anxiety, trauma, or difficulties with emotional regulation. Therefore, self-injury does not in itself cause suicidal behavior, but rather it is the same vulnerable emotional state that can lead a person to self-harm, have suicidal thoughts, attempt suicide, or commit suicide. In this case, non-suicidal self-injury is an indicator of vulnerability and not directly the cause of suicidal risk.
When self-harm becomes a recurring behavior, it becomes a risk factor that increases the likelihood of attempting suicide.
3. Thomas Joiner's Interpersonal Theory of Suicidal Behavior
This is the model with the most support. According to this model, committing suicide requires going through three stages, from suicidal thoughts to the act itself.
- First, there is the development of suicidal ideation , which is when a person begins to think about death and when two key experiences arise: the feeling of not belonging (I am alone) and the feeling of being a burden to others. This generates the desire to die.
- Secondly, there is what is called acquired suicidal capacity . It is at this stage that non-suicidal self-harm comes into play. Through this self-harming behavior, the person repeatedly exposes themselves to pain and reduces their fear of harming themselves, thus diminishing the natural protection of the survival instinct.
- Thirdly, we have suicidal behavior , which occurs when the desire to die and the ability to do so coincide at the same time, having lost the fear of feeling pain from the repeated practice of non-suicidal self-harm.
Conclusion
The relationship between non-suicidal self-injury and suicidal behavior lacks a single explanation. Some theories understand non-suicidal self-injury as the beginning of a continuum toward suicidal behavior, others consider that non-suicidal self-injury and suicidal behavior share common factors, and some theories suggest that non-suicidal self-injury contributes to diminishing the survival instinct and, ultimately, empowers the person to engage in suicidal behavior.
