Factors influencing the length of stay in forensic psychiatric settings: a systematic review

Forensic psychiatry (FP) has the complex task of caring for mentally disordered offenders: assessing and treating mental illness and simultaneously protecting the public interest where individuals are deemed dangerous [1, 2]. FP has taken on different forms across the world and has developed to different extents [2]. Its scope stretches across several settings: courts, general psychiatric settings, communities, prisons and dedicated forensic psychiatric hospitals. In some places, specialist FP is not available at all [3]. Naturally, FP is heavily intertwined with and dependent on the criminal justice system given its target population, and it is usually up to the justice system to weigh forensic psychiatrists’ expert opinion, decide on criminal responsibility and whether and where a custodial sentence must be served [4].

While the management of forensic patients includes rehabilitation and reintegration into society, protecting the public from potentially dangerous individuals remains an important consideration. Forensic inpatients have lengths of stay (LOS) spanning months or, more commonly, years, increasing in the past decades [5]. These admissions can have LOS that are shorter, equivalent, or sometimes longer than times in detention for imprisoned offenders for the same charge [6]. A high-security bed in the United Kingdom (UK) will be occupied by a forensic service user for an average of 70 months and a medium-security for 26 months [7]. A 2018 survey of 23 medium- and 3 high-security hospitals in England identified 23.5% of inpatients as “long-stayers”, defined as inpatients staying for more than 5 years in medium-security and more than 10 years in high-security services [8]. This phenomenon is not limited to the UK; in Brazil, the average LOS in forensic hospitals was 6 years [9], whereas in the Netherlands, the duration was greater at 8 years [8]. The longer LOS of forensic admissions is also apparent within specific diagnoses. In a 2008 study, patients with schizophrenia spent more days per year hospitalised when they had a forensic admission compared with those who had a non-forensic admission [10].

Forensic mental health services come at a great cost owing to the complexity of care. In the 2019 Scottish government inpatient census, the total number of patients being cared for in a forensic ward in Scotland was 412 [11]. in a population of 5,479,900 people; this highlights the small patient population admitted to such units. According to the Centre for Mental Health Care in the UK, the average cost per annum in England for low-security and medium-security beds is £153,300 and £176,295, respectively, while the cost for high-security beds ranges from £271,560 to £357,335 depending on the specific service [12]. High-security beds in Scotland come at comparable costs, approximately £6195 a week and £322,140 per annum in 2009/10 [13]. Overall, secure care services cost the NHS £821 million in England in 2018/19, corresponding to 10.9% of all public expenditure on mental health services [14]. This high cost is not limited to the UK. In the Netherlands, a forensic bed costs an average of 388 euros per day, adding up to 141,620 euros per patient per year [15]. In Japan, the cost of a forensic bed is US$186,019 per year [16], a cost 4.4 times higher than a non-forensic involuntary admission [17]. This cost, however, must be understood within the broader healthcare landscape and it is essential to recognise the value these services provide. Alternatives such as prolonged high-security imprisonment may incur comparable or even higher expenses, not to mention potentially inferior outcomes in terms of rehabilitation and recidivism rates.

While high cost is one reason to aim for a shorter LOS, the harms of longer admissions must be considered. A lengthy admission can adversely impact patient outcomes and quality of life and reduce the likelihood of future independent living by the individual [18]. Furthermore, it can lead to institutionalisation and social withdrawal [19] and greatly limit autonomy. Forensic environments are by default highly restrictive, with great emphasis placed on security of the individual and others [20], so a longer admission can result in sometimes unnecessary [21] prolonged deprivation of civil liberties for the individuals [22].

However, at present, there is no widely accepted definition of what constitutes a “long LOS” in forensic services; the Butler Committee on Mentally Abnormal Offenders interim report published in 1975 [23] and the Glancy report published in 1973 [24] by the Department of Health and Social Security and the Home Office recommended a maximum 18-month to 2-year stay for medium secure units before an alternative placement is sought. However, these were mere recommendations; research across the UK has repeatedly demonstrated that the LOS in medium- and high-security forensic hospitals often exceeds these numbers [5, 25‐27]. It is also worth noting that the original Glancy Report envisaged that “a significant number of patients are likely to require secure accommodation for longer than 18 months to two years”. Moreoever, there is no definition of LOS (prolonged or otherwise) in the forensic inpatient setting described in the most recent “Standards for Forensic Mental Health Services” by the Royal College of Psychiatrists and the Forensic Quality Network for Forensic Mental Health Services published in 2019 [28].

Huband et al [29] attempted in 2018 to define what constitutes “long stay” but found that reports were inconsistent across documents and thus it was not possible. They did, however, highlight some characteristics that may contribute to a long stay, such as “seriousness of index offence, history of psychiatric treatment, cognitive deficit, severity of illness, history of violence, and history of substance misuse”. This persistent lack of definition of an appropriate LOS from national and international bodies poses significant challenges in research, as investigators have to come up with their own definitions.

In light of the high cost and complexity of care, it is essential to understand what a prolonged admission is and what factors contribute to a longer LOS in FP. The reasoning is dual: from a public health and economic perspective, the financial burden of forensic admissions is heavy and increasing. From a patient-centred care perspective, the potentially detrimental effects of a prolonged admission, albeit being poorly defined, in such restrictive environments must be mitigated. Understanding contributing factors means that services can develop mechanisms to better address prolonged stays and patients’ needs.

While most factors that contribute to LOS are non-modifiable, such as sociodemographic characteristics and forensic or psychiatric history, special consideration must be given to the modifiable factors. Forensic care takes place in a complex system that involves a range of interventions that could influence LOS, such as pharmacological, psychological [30], and occupational therapies [31] or risk management-focused activities.

To date, there has been no systematic review or meta-analysis focusing on the factors influencing LOS as a primary outcome. The main aims of this systematic review were to identify modifiable and non-modifiable factors associated with LOS in forensic psychiatric hospitals and to identify gaps in the relevant literature to formulate recommendations for future research.