Psychopathology, or the manifestation of a mental or behavioural disorder, can be a factor in many cases of arson. Psychopathologic firesetting may be motiveless, where the person acts in a psychotic state or in response to delusions or other manifestations of a psychiatric disorder such as schizophrenia. In other cases there may be a motive such as revenge or the desire for attention which is influenced by a personality disorder. Deficits in judgment and reasoning resulting from an intellectual disability may lead to a person lighting a fire without fully appreciating the consequences.
Disorders such as schizophrenia result from a combination of genetic factors and problems with brain development resulting from prenatal environmental stressors. Stressors may include maternal drug use, poor nutrition or exposure to severe trauma. Imbalances in nervous system chemicals are seen in many patients. Personality disorders result from similar causes, but are often triggered by environmental influences in early childhood, such as being raised in an abusive or otherwise dysfunctional environment.
A number of studies have examined the frequency with which firesetting results from psychopathologic influences. Examining 153 arsonists referred for pre-trial psychiatric assessment, Rix (1994) found 54 per cent had a personality disorder and only 13 per cent did not quality for a psychiatric diagnosis of some kind. Rix also found a significant incidence of intellectual disability (10%) and schizophrenia (6%) in his sample. In a study of 283 arsonists, mostly sourced through FBI files, Ritchie and Huff (1999) found 90 per cent had recorded mental health histories. Thirty-six per cent had a major mental illness of schizophrenia or bipolar disorder. Three of the 283 arsonists (1%) were diagnosed with pyromania.
Studies such as these are not representative of all arsonists and firesetters. They may be drawing on samples that have been pre-selected for psychiatric assessment. They also only include subjects who have committed relatively serious offences and have been caught for them. In many cases it may be that the individual's psychiatric disorder has contributed to them being caught, particularly given the overall low rate of detection, arrest and conviction for arson offences. It is possible that a given subject may have an underlying disorder without this necessarily playing a part in their firesetting behaviour.
The prevalence of psychopathology in bushfire-specific arson is not clear. This is due to a lack of focused studies and relatively low rates of arrest and conviction. In many cases people will light bushfires for reasons that are illegal, yet essentially rational, such as fires lit for land management purposes. Teenagers lighting fires in a group, for instance, will usually be responding to peer pressure and boredom rather than a psychiatric disorder. In cases where an offender lights a series of fires with no apparent purpose other than to fulfil their own psychological needs, there is a likelihood of them displaying at least some psychopathological symptoms.
- Davis JA & Lauber KM 1999. Criminal behavioral assessment of arsonists, pyromaniacs and multiple firesetters: the burning question. Journal of contemporary criminal justice 15(3): 273-290
- Rix KJB 1994. A psychiatric study of adult arsonists. Medicine, science and law 34(1): 21-34