Sleeping Rough – Acting Tough: Is Mental Illness a Precedent for Homelessness?

Approximately 380,000 individuals in the United Kingdom and 740,000 individuals in the United States are reported to be homeless at any given time. A majority of these individuals are also likely to be plagued by mental illnesses that generally go undiagnosed and untreated. The resulting self-medication with substance abuse and associated anti-social behaviours further exacerbates stereotypes and alienates homeless people from accessing social services. Clare Allely delves into the root of the problem and asks if there is a way out of the negative spiral of rough sleeping.

Most people would generally define a homeless person as someone who ‘sleeps rough’. This is an oversimplification however, as there are a number of other situations in which people can be insecurely housed and/or at risk of homelessness, such as living in a hostel, ‘sofa surfing’, and staying with friends or family – typically for short durations. Furthermore, homelessness has also been linked to a variety of anti-social behaviours, which frequently result in eviction – particularly for rough sleepers or those living in hostels or night shelters. Typically, these behaviours contravene the rules of the establishment, such as consuming alcohol on the premises or returning obviously intoxicated, owning, obtaining, or consuming illegal substances, and violence or aggression. Such behaviour has contributed to the myths and stereotypical beliefs that homeless individuals are untreatable, or represent an unsuitable portion of the population and are therefore undeserving of treatment. A homeless person is therefore not only defined by their living circumstance, but is also often a victim of it. From the perspective of mental health treatment, a typical client who has either experience of, or is vulnerable to, sleeping rough will most likely have highly complex needs involving issues such as poor emotional wellbeing, mental illness, personality disorder, and poly-substance use. Whether such mental illness is a product or a cause of homelessness remains an open and largely unexplored question. A greater quantitative understanding of the causal links between mental illness and homelessness may be the key to breaking the cycle of alienation.

Mental Health and Homelessness

Research suggests that behaviour which can increase the likelihood of homelessness may be associated with mental health problems such as post-traumatic stress disorder (PTSD), complex trauma, conduct disorders in children, attachment disorders, and borderline personality disorder (BPD), particularly when interpersonal problems and self-harm are evident. Despite much support for an association between homelessness and complex trauma, there is some debate as to the exact nature of the relationship between the two. Some studies have shown that homelessness itself is a risk factor for trauma 1, whereas others noted that trauma precedes homelessness 2. Another study attempted to quantify this relationship 3 and found that for almost three-quarters of cases, post- PTSD preceded the onset of homelessness.

Complex trauma (or Complex PTSD, Type II Trauma) is a term used to describe the psychological issues and linked patterns of thoughts, feelings and behaviours which typically occur as a consequence of prolonged exposure to traumatic experience where there is no apparent escape such as hostage situations, torture, any form of childhood abuse, and domestic violence. For circumstances in which the ongoing traumatic experience occurs within the context of a care relationship (parents or caregivers are the primary abusers), attachment processes can be detrimentally affected. This may then cause problems in forming relationships later in life as well as problems with regulating emotions.

Together, this research suggests that a significant factor contributing to homelessness is not anti-social behaviour in itself, but underlying and pre-existing mental health problems. Because of a clear lack of a support system, mental illnesses in the homeless population often remain undiagnosed and therefore untreated. Generally, there are higher rates of mental health problems amongst rough sleepers and young people who have experienced homelessness than in the general population. Furthermore, these are the groups who are most likely to present challenges to conventional mental health services and will ultimately fail to access mainstream mental health services. A systematic review 4 revealed that the prevalence of psychotic illness and major depression in the homeless population in Western Europe and North America ranged from 2.8% to 42.3%, most notably characterised by PTSD and personality disorders. However, the most common mental disorders found were alcohol (8.1% to 58.5%), and drug (4.5% to 54.2%) dependence, all of which may or may not be mutually exclusive.

Post Traumatic Stress Disorder

Post traumatic stress disorder (PTSD, Type I Trauma) is an anxiety disorder usually caused by exposure to a highly traumatic event in which personal safety or integrity is seriously threatened. The symptoms can include: re-experiencing the original trauma in the form of flashbacks or nightmares, avoidance of situations associated with the trauma, increased arousal and anger outbursts, sleep difficulties, and hyper vigilance for threat. International studies indicate high prevalence rates of post-traumatic stress disorder within the homeless population. In Australia, although high rates of trauma are reported among homeless adults, post-traumatic stress disorder has largely not been explored. One study carried out in Sydney aimed to determine the prevalence of PTSD among homeless adults, and whether the onset of PTSD preceded the first episode of homelessness or was a consequence of it 5. Overall, the study indicates a high association between PTSD and homelessness. The surveyed population consisted of seventy homeless men and women aged 18–73 years, 98% of who had experienced at least one traumatic event in their lifetime (the mean number of traumas per person was six). The general prevalence of PTSD was substantially higher among the homeless sample with respect to the general Australian population (41% vs 1.5%). Specifically, 79% of the sample had a lifetime prevalence of post-traumatic stress and 59% of cases reported the onset of PTSD as preceding the age of the first reported homeless episode. These findings are consistent with an earlier study led by Dr. Carol North at the Washington University of Medicine, USA 6. In nearly 75% of the six hundred homeless men and three hundred homeless women interviewed in St. Louis, the onset of PTSD had preceded the onset of homelessness. Therefore, factors giving rise to PTSD appear to begin well before individuals find themselves homeless, and may in fact be a contributing agent as the authors of the study conclude that PTSD “may overlap with factors operative in the genesis of homelessness”. Furthermore, the majority of individuals with PTSD had an additional life-time psychiatric diagnosis, such as personality disorders.

Personality Disorder

Personality Disorder (PD) is a condition similar to PTSD, as it is also a response to traumatic experience. Unlike PTSD, however, PD is usefully described as ‘complex trauma’, which generally refers to responses to an ongoing and sustained traumatic experience. PD is characterised by various emotional, cognitive and behavioural factors which may often play a direct part in repeated tenancy breakdown. The behaviour observed in individuals with PD can be seen as both reactions to and ways of coping with the traumatic experience of a difficult childhood. The following are the diagnostic criteria associated with BPD set out by the North American Diagnostic and Statistical Manual (DSM): a pattern of intense and unstable interpersonal relationships; frantic efforts to avoid real or imagined abandonment; identity disturbance or problems with sense of self; impulsive behaviour that is potentially self-damaging; recurrent suicidal or parasuicidal behaviours; affective (emotional) instability; chronic feelings of emptiness; inappropriate or uncontrollable anger and transient stress-related paranoid ideation or severe dissociative symptoms (i.e. paranoia induced by stress, and ‘dissociation’ – a process of ‘removing’ oneself from reality typically learned during episodes of early abuse).

Not all individuals who have been homeless will have experienced a traumatic childhood experience or be diagnosed as experiencing complex trauma. Nonetheless, there is increasing evidence that a significant proportion may suffer from complex trauma, particularly those with very complex needs such as entrenched rough sleepers or young people who have endured sustained traumatic experiences before facing homelessness. Although the prevalence of PDs in the homeless population has been explored by numerous studies, the extent to which PDs may be implicated in the aetiology and/or maintenance of homelessness remains unclear. Despite the fact that relatively few studies have systematically diagnosed PD among the homeless, unstructured clinical assessments suggest rates up to 70% (although rates are highly varied) identifying schizoid, borderline, dependent, and antisocial features 7. Specifically, rates of antisocial personality disorder in America range between 10-40% and the prevalence of PD in a UK population of street homeless and hostel dwelling adults revealed that 58% reached diagnostic levels. There is also increasing evidence of many inter-linked difficulties – what in medical terms is called ‘co-morbid symptomatology’. For instance, PD combined with other complications or associated and clinically comparable problems such as substance abuse, suicide, frequent A&E presentations and PTSD.

Individuals with complex trauma who have experienced homelessness may behave in a variety of ways that indicate underlying difficulties with relationships or with managing their emotions. Some individuals may self-harm, have an uncontrolled drug and/or alcohol problem, or exhibit anti-social or aggressive behaviour. They may appear impulsive and not give any thought to the consequences of their actions and lack any structure or regular daily routine. They may appear withdrawn or socially isolated, be reluctant to engage with offered help, not have been in work or education for significant durations of time or have committed a criminal offence. Individuals who have experienced homelessness frequently come to expect rejection and as a result they find it a struggle to trust people who are trying to help them and talk freely about problems in their lives. Previous unsatisfactory experiences of housing, health or care and support services contribute to a mistrust of authority or bureaucratic systems, regardless of the good intentions of the service provider. Adding complex trauma to the mix makes such individuals even more difficult to engage with, as they will be likely to display volatile, irresponsible, risky or antisocial behaviour. In some cases, particularly for those that aren’t receiving appropriate treatment for mental illness, drugs and/or alcohol are used as self –medication tools. Such abuse can further exacerbate mental health issues and antisocial behaviours, therefore increasing the difficulties in working with this population.

Drugs and Alcohol

Mental Health Services describes the misuse of alcohol and/or drugs by individuals with mental health issues, as a “dual diagnosis”. Although it is unclear whether substance abuse is a cause or a consequence of mental illness, Dialectical Behaviour Therapy (DBT) highlights the role of substance and alcohol use as an ‘emotion regulation strategy’. For some individuals who have difficulty in regulating their emotions, taking drugs or alcohol is the quickest way to change their internal state, both cognitively and emotionally. The use of drugs dulls or eliminates emotions; a process often termed ‘experiential avoidance’. One of the strongest motivations for continual use of drugs is to prevent the difficult physical symptoms that occur with non-use. Studies suggest that some individuals believe that using drugs enables them to maintain relationships, through either a reduction in inhibitions or through a peer group centred round the acquisition and use of a particular substance.

Because access to services is often conditional on abstinence from drugs and/or alcohol, proper diagnosis of mental illness is imperative to break the cycle of substance abuse, particularly for those who also experience complex trauma. Unless the underlying causes of the complex trauma are diagnosed and treated, substance misuse is highly likely to continue. As this diagnosis is commonly a lengthy and painful process, denying access to accommodation or mental health services on the grounds of ongoing substance misuse is likely to result in both sustained rough sleeping and poor health. At the same time however, services must be in place to ensure and maintain the safety of staff and residents. It is therefore crucial to disentangle those individuals who use drugs and alcohol as way of coping with complex trauma from those whose drug and alcohol use may largely be recreational while still being problematic.

Where do we go from here?

Because the above factors (PTSD, PD and substance abuse) are difficult to tease apart with respect to their relationships to homelessness, developing services that recognise both the psychological and emotional needs of individuals with complex trauma issues is likely to result in positive outcomes, both for homeless individuals with preceding mental illness and for those who may have been adversely affected by the experience of homelessness but who may not have such complex and entrenched problems. Importantly, it is becoming increasingly apparent that the homeless population does not have a single definition, and is certainly more than a group of rough sleepers. The prevalence of dual diagnosis – mental illness and substance abuse – adds even more heterogeneity to the population. This heterogeneity includes factors such as demographics, pathways to homelessness, type and severity of non-addictive mental disorder, and type and pattern of substance use disorder(s), which makes it difficult to generalise about the dually diagnosed homeless population. There are two areas that merit further investigation. First, the extent to which ‘complex trauma’ acts as both a causative and maintaining factor for homelessness needs to be addressed and a common understanding created. Second, more research is required to investigate how the resulting personality disorders lead to entrenched or repeated homelessness. Positive outcomes will most likely be achieved by directing clients away from ineffective and destructive coping strategies, such as substance abuse, toward strategies that will help to maintain healthy relationships or accommodation.



  1. Goodman LA, Saxe L, Harvey M. Homelessness as psychological trauma: Broadening perspectives. American Psychologist, 1991
  2. Taylor KM, Sharpe L. Trauma and post-traumatic stress disorder among homeless adults in Sydney. The Australian and New Zealand Journal of Psychiatry, 2008; 42: 206-213
  3. North CS, Smith EM. Posttraumatic stress disorder among homeless men and women. Hospital and Community Psychiatry, 1992
  4. Fazel S, Khosla V, Doll H, Geddes J. The prevalence of mental disorders among the homeless in western countries: systematic review and meta-regression analysis. PLoS Med, 2008
  5. North CS, Smith EM. Posttraumatic stress disorder among homeless men and women. Hospital and Community Psychiatry, 1992
  6. North CS, Smith EM. Posttraumatic stress disorder among homeless men and women. Hospital and Community Psychiatry, 1992
  7. Tolomiczenko GS, Sota T, Goering PN. Personality assessment of homeless adults as a tool for service planning. Journal of Personality Disorders, 2000

You may also like...

1 Response

  1. Torsten says:

    What’s up, after reading this amazing post i am too
    delighted to share my knowledge here with colleagues.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.