Table 5.

Barriers and facilitator themes and sub-themes mapped to NPT constructs and sub-constructs.

NPT	Barriers		Facilitators
1.  Coherence
1.1 Differentiation	HP	Fear PGxT may replace (rather than complement) existing prescribing practices [62,67,68]	B	Perception that PGx offers an improved approach to prescribing [62,64,88]
	Pa	Perception that PGxT is an extension of the medical model of psychiatry [64]	B	Better than trial-and-error approach [62,68,83,88,90]
			B	May improve evidence-based medicine in psychiatry [81]
1.2 Communal Specification	B	Lack of consensus about purpose and potential benefits of PGxT [65,67,75,81,87]	B	Perception that PGx is a tool to help guide prescribing and support clinical decisions to improve prescribing outcomes [62,63,67,68,72,75,76,77,79,81,83,84,89]
	HP	HCPs: when and who to offer PGxT, and disagreement about what PGxT can achieve and how information is used [68,72,75,81,90]	B	Particularly for prescribing in depression and schizophrenia following ADRs or inefficacy [65,66,67,68,69,72,75,76]
	Pa	Patients: misunderstanding of how PGx data is used (e.g., in diagnosis or prognosis) and unrealistic expected benefits for PGxT [64,70,83]	Pa	Additional information and counselling given to patients during PGxT helps feel more informed about their medication and illness [68,77,84]
1.3 Individual Specification	HP	Lack of understanding about what PGxT entails and requires of them [66,67,68,81,87]	HP	Experience helped stakeholders understand what PGx requires of them [65,68]
	B	Patient lack of awareness about what PGxT is [68,70,73,74,75,82,84]	HP	Both personal experience and access to those with experience of using PGxT [68]
	Pa	Patient understanding of PGxT involves for them may fluctuate based on mental health status [64]	HP	Prescribers believed not acting on or using PGx results would not cause liability issues [65]
1.4 Internalisation	B	Belief that PGx currently lacks evidence to support clinical utility, specifically for: [62,65,72,79,87,88]	B	Perception that PGx has a range of potential HCP, individual, and system benefits and values: [62,63,81,83,84,87,88]
	HP	Efficacy [62,65,72,79]	HP	HCP—help inform medicine choice [63,68,81,85] and dose [65,68,71], help build rapport with patients [66,67,69], inform medication reviews and clinical decisions [69,85]
	HP	Adverse Drug Reactions [65,72]	B	Patient—⇩ADRs [63,64,81,83,87], ⇧efficacy [72,81,88] and ⇩time to find suitable medicine [75,76,83]
	B	Adherence [83]	B	System—⇩health costs [81,83], and ⇩frequency [70] + ⇩length of hospital admissions [68]
	B	Concern that PGxT may cause harm or distress [63,65,66,67,68,71,72,75,77,83]	HP	Belief that PGx can help engage patients in shared decision making [67,68,69,85]
	HP	Increase health inequalities [65,68]	B	Agreement that PGx can reassure patients by reducing uncertainty about taking a medicine [67,68,69,73,83,84]
	B	Perpetuate existing issues in mental health (e.g., increase stigmatisation or discrimination) [65,77,83]	HP	Especially those who are medication naïve [68]
	B	Perception that PGxT is not cost-effective [68,76,81]	B	PGx can validate previous medication experiences [67,68,76,83,87,88]
2.  Cognitive Participation
2.1 Initiation	Ps	Some psychiatrists do not believe they are appropriate to drive implementation, in part due to:	B	Strong interest in adopting PGxT, due to belief it will yield patient, HCP, and system benefits [62,65,66,72,73]
	Ps	Lack of skills and knowledge relating to PGx [68,75,87]	HP	Belief that pharmacists are important in PGx implementation [62,68,90]
	Ps	Lack of confidence in PGx being effective [78]	HP	MDT approach to monitoring PGx outcomes is desired [86,90]
2.2 Enrolment	B	Perceived difficulty to integrate PGx into existing clinical pathways and services [69,70,88]	HP	Willingness from psychiatrists and prescribers to engage with other HCPs during implementation, particularly [68,86,90]:
			Ph	Pharmacists—perception that their role in PGx education, PGx patient counselling, PGx results interpretation and clinical service development will be key [68,90]
			HP	Genetic Counsellors—belief they can play a role in discussing PGx with patients [84,85]
			HP	Trust is key when HCPs collaborate on PGx [69,90]
2.3 Legitimation	Ps	Psychiatrist uncertainty about when to offer PGxT to patients—some psychiatrist sub-populations less likely to consider PGxT were: [66,75]	Ps	Psychiatrists believe PGx should be within their scope of practice [66,71,72]
	Ps	Older/more experienced psychiatrists [78]	Ps	Particularly offering PGx as an option to patients [66]
	Ps	Psychiatrists adopting a more psychosocial approach to mental health [75]	Ph	Pharmacists perceive PGx to be part of their clinical role expansion [90]
	Ps	Perception amongst psychiatrists that others in the profession lack the knowledge required to utilise PGxT [63]
2.4 Activation	B	Ethical concerns about PGx tasks and activities [62,75,83,84]	HP	Agreement in tasks required to sustain PGx [68,72]
	HP	Gaining patient consent [62,72]	HP	Including obtaining consent [71,72], patient counselling [72], results interpretation, sharing results and updating results [68,69]
	B	Storage of genetic data and privacy issues [62,63,64,68,70,75,83,84]	HP	Belief that they can facilitate PGx-related activities [67,68,86]
	Ps	Psychiatrist concern about capacity to counsel patients about PGx and depth of information to provide [75,88]	B	Educating patients is essential [65,86] and improves their perception of PGx [68,70,76,82]
	HP	Concern about updating PGx results—as new evidence emerges [69,83]
3.  Collective Action
3.1 Interactional Workability	HP	PGx may create extra burden during prescribing [67,68,69,75]
	HP	Due to additional time required to complete PGx-related tasks [67,68,69,72]
	B	Delay in obtaining PGx results can be problematic [67,68,70,74,75,83,88]	HP	PGx can help make prescribing decisions easier when PGx is delivered in a timely and accessible manner [74]
	HP	If PGx reports are too long or detailed [68]	B	PGx can make it easier to build patient rapport [66,67,83]
	Ps	If psychiatrists need to access support to utilise PGx results [63,67]
	B	PGx may hinder rapport-building with patients [62,63,75]
	B	Risk of misinterpretation of PGx results, particularly traffic-light systems of reporting that may oversimplify decision-making [68,76,88]
3.2 Relational Integration	B	Lack of confidence in PGxT as an intervention, due to doubts over: [65,68,76,83,85]	HP	Perception that PGxT is safe and reliable helped contribute to confidence in PGxT as an intervention [62,68,72,75]
	HP	Ability of PGx to improve clinical outcomes [65,68,85]	HP	A belief that PGxT is a promising strategy to prescribing that will change practice and become a normal part of prescribing [62,66,71,72,75,85,87,89,90]
	Ps	Likelihood of PGx to influencing prescribing decisions [75,85]
	B	Cost of conducting PGxT [62,63,66,67,68,72,75,76,81,83,84,87]
3.3 Skillset Workability	HP	HCP knowledge and expertise gap for PGx in psychiatry [66,68,75,81,87]	HP	Relevant training and experience helps HCPs to be sufficiently knowledgeable and confident to use PGx [65,66,72,80]
	Ps	Psychiatrists lack awareness of the guidance for using PGxT in psychiatry [62,63,65,66,75,87,88]	B	Stakeholders are enthusiastic to learn more about PGx [62,66,70,75]
	Ps	Psychiatrists did not feel informed enough to identify when to offer PGxT or utilise PGxT results [66]	HP	Through e-learning, case studies, lectures and formal qualifications [62,66]
	Ps	Patient perception that HCPs may lack expertise to offer and use PGxT [83]	Ph	Pharmacists are confident in identifying when to offer PGx [66] and provide PGx counselling [90]
			Pa	Depressed patients have the psychological capacity to deal with PGx results [77]
			B	PGx education informs patients and manages expectations [76]
3.4 Contextual Integration	HP	Perceived lack of internal and external policy on PGx [71]	HP	Belief that psychiatry specific, practical PGx guidelines would help implementation [65]
	HP	Belief that there is a lack of basic and specialised education and training about PGx [62,63,68,72,75,90]	HP	Perception that national and international policy on PGx would help implementation [63,65,86]
	HP	A notion there is a lack of guidance and resources available to implement PGx [62,63,65,71,87]	HP	Staff and leadership engagement helped local implementation [80,86]
	Pa	Patients perceived to have a lack of education and awareness about PGx [70,73,74,82]	HP	Adoption of local PGx champions helps implementation [80,86]
4.  Reflexive Monitoring
4.1 Systemisation
4.2 Individual Appraisal			HP	HCPs used their own clinical judgement to appraise PGx outcomes [90]
4.3 Communal Appraisal
4.4 Reconfiguration			HP	Preference to adapt PGx for specific contexts, based on experience and feedback [88]

Description: Displayed in the table are the constructed barriers and facilitators mapped onto different constructs and sub-constructs of the NPT framework, and which stakeholder group the barrier or facilitator was constructed from: HP = healthcare professional, Pa = patient, B = both, Ps = psychiatrist and Ph = pharmacist. Sub-themes start with bullet points. ⇩ = decreased; ⇧ = increased.