Diversity or disarray? A systematic review of decision-making capacity for treatment and research in schizophrenia and other non-affective psychoses

Abstract

Background. Valid consent for treatment or research participation requires that an individual has decision-making capacity (DMC), which is the ability to make a specific decision. There is evidence that the psychopathology of schizophrenia can compromise DMC. The objective of this review was to examine the presence or absence of DMC in schizophrenia and the socio-demographic/psychopathological factors associated.Methods. We searched three databases Embase, Ovid MEDLINE(R), and PsycINFO for studies reporting data on the proportion of DMC for treatment and research (DMC-T and DMC-R), and/or socio-demographic/psychopathological associations with ability to make such decisions, in people with schizophrenia and related illnesses.Results. A total of 40 studies were identified. While high levels of heterogeneity limited direct comparison, meta-analysis of inpatient data showed that DMC-T was present in 48% of people. Insight was strongly associated with DMC-T. Neurocognitive deficits were strongly associated with lack of DMC-R and to a lesser extent DMC-T. With the exception of years of education, there was no evidence for an association with socio-demographic factors.Conclusions. Insight and neurocognitive deficits are most closely associated with DMC in schizophrenia. The lack of an association with socio-demographic factors dispels common misperceptions regarding DMC and characteristics such as age. Although our results reveal a wide spectrum of DMC-T and DMC-R in schizophrenia, this could be partly due to the complexity of the DMC construct and the heterogeneity of existing studies. To facilitate systematic review research, there is a need for improvement within research study design and increased consistency of concepts and tools.

Unwell in hospital but not incapable: cross-sectional study on the dissociation of decision-making capacity for treatment and research in in-patients with schizophrenia and related psychoses

“…Schizophrenia and related psychoses (such as schizoaffective disorder, delusional disorder, and acute and transient psychoses) are commonly associated with impairments in DMC. 1 This may influence the decisions of institutional review boards or research ethics committees when it comes to recruiting research participants with these conditions. However, there is an indisputable need for more research in schizophrenia and related psychoses, 2 especially with participants who are detained in hospital, severely unwell, or with chronic illness and prominent negative symptoms – people for whom there is evidence of systemic exclusion from research studies.…”

“…Participation in human research either requires the consent of participants (with DMC for research, DMC-R), or that of the legally authorised representative in those lacking DMC-R. 5 If an individual objects to participation, irrespective of their DMC-R, the objection is always respected. 5 However, the psychopathology of schizophrenia and related psychoses can have a substantial impact on both DMC for treatment (DMC-T) and DMC-R (for a review see Spencer et al , 2017 1 ). There is a moral imperative to adequately protect people from the consequences of a decision made when DMC is lacking, but also to ensure autonomy is respected and that DMC is maximised.…”

Evidence on the capacity of severe mental disorder patients to make well-founded decisions about their healthcare: a meta-review

“…The MacArthur Competence Assessment Tool for Treatment (MacCAT-T) was the primary assessment instrument in eight reviews, while two reviews used the Iowa or Canada Gambling Tasks to assess capacity to make decisions. Nine of the reviews included in the present report were conducted by authors in European countries (12) (15) (17) (19)(20)(21)(22)(23)(24), two were based in the United States (14) (18), one study was conducted in Australia (16), and another in several countries (13) (Table 4).…”

“…One systematic review of 37 empirical, quantitative studies of mental capacity in a mixed population of psychiatric patients reported that up to 67% of participants had the capacity to decide whether to be admitted to a psychiatric unit while a median of 71% had capacity for making treatment decisions (a median of 29%, interquartile range (IQR) 22-44, lacked capacity) (21). Another systematic review found that 26% (95% confidence interval (CI): 18 to 36) to 67% (95% CI: 35 to 88) of people with schizophrenia or other non-affective disorders were able to make medical decisions related or unrelated to the management of their condition (22). Overall, the definitions and measurement of capacity varied widely in the studies (21) (22).…”

“…Another systematic review found that 26% (95% confidence interval (CI): 18 to 36) to 67% (95% CI: 35 to 88) of people with schizophrenia or other non-affective disorders were able to make medical decisions related or unrelated to the management of their condition (22). Overall, the definitions and measurement of capacity varied widely in the studies (21) (22).…”