An FASD diagnosis is most commonly acknowledged to be a mitigating factor at sentence, and appellate courts that have considered the issue generally agree that this is the correct view for a sentencing judge to take (e.g. R. v. Andrew, 2008 BCCA 141 and R. v. Ramsay, 2012 ABCA 257, but also see R. v. IDB, 2005 ABCA 99). The importance of an FASD diagnosis to the determination of an appropriate sentence is evidenced by the fact that the diagnosis is admissible as fresh evidence on a sentence appeal (R. v. Synnuck, 2005 BCCA 155, see also R. v. Hubley, 2009 PECA 21, R. v. C.P., 2009 NBCA 65, R. v. Dennis, 2013 BCCA 153), and a sentencing judge’s failure to take FASD into account can be a reversible error (Synnuck, R. v. Ramalho, 2004 BCCA 617).

FASD has been viewed as decreasing the relevance of denunciation and deterrence as sentencing objectives (R. v. Harper, 2009 YKTC 18, R. v. Blanchard, 2011 YKTC 88, R. v. F.J.N., 2012 ABPC 81, Ramsay, R. v. Laquette, 2015 MBQB 79, R. v. Quash, 2009 YKTC 54), and the focus in the decision between a custodial and non-custodial sentence is premised more on the need for separation and the ability to achieve rehabilitation through structured modification of behavior. More serious crime means protection of the public gets more emphasis (R. v. Keewatin, 2009 SKQB 58). The step principle does not apply to an offender with FASD (R. v. Charlie, 2015 YKTC 17, aff’d 2015 YKCA 3).

Considerations about the deficits that arise with FASD can lead to grossly different sentences. For example, in R. v. Becker, 2009 ABPC 227, the Court determined that jail was a more appropriate sentence than a CSO because of difficulty controlling the offender in the community, but the opposite conclusion was reached in Ramalho where the BCCA found it was an error to reject a CSO because of the offender’s FASD.
Some courts have held that jail is detrimental to someone with FASD. Concern has been expressed that jail is counterproductive as it reinforces anti-social tendencies, given an affected individual’s suggestibility, and it was determined that the greatest chance for rehabilitation is within the community (R. v. Soosay, 2012 ABPC 220). As well, it has been observed that the penal system is not intended as a catchment basin for people with disabilities, and there is a social obligation on the justice community and the community at large to provide suitable supports outside of prison (R. v. Passmore,2014 SKPC 38, R. v. Linklater, 2012 YKTC 68).
However, the opposite conclusion has also been drawn. In R. v. D.J.R., 2006 BCCA 125 the court found that rehabilitation is best achieved in a custodial setting. There is also a perception that the federal system is better able to meet the needs of offenders with FASD, which can lead to longer sentences being imposed: R. v. D.R.B., 2004 BCPC 47, R. v. Pauls, 2005 BCPC 602, R. v. Obed, 2006 NLTD 155, R. v. Malcolm, 2005 YKTC 25, R. v. J.J.P., 2011 BCPC 468. There are also cases where an offender’s time in custody was extended beyond what might otherwise have been the appropriate sentence to allow the development of a release plan (R. v. Williams, 1994 CanLII 576, R. v. Charlie,2012 YKTC 5, R. v. Kendi, 2011 YKTC 37).

It is an error to judicially diagnose FASD (R. v. Harris, 2002 BCCA 152, Synnuck, R. v. R.R.G.S., 2014 BCPC 170). There may nevertheless be some relevance to evidence about FASD falling short of a diagnosis (R. v. C.O., 2006 NWTCA 3, R. v. Morgan, 2013 BCPC 99, R. v. Green, 2013 ONCJ 423, R. v. Brown, 2014 ABPC 236, R. v. McKenzie-Sinclair, 2015 MBPC 5). In Linklater, there had been no assessment of the accused despite two court requests and the recommendation of a number of professionals, but a psychological report ordered detailing his limitations was sufficient for sentencing purposes. In R. v. Decouteau, 2013 ABPC 277, the lack of a diagnosis in the context of suspected FAS meant that offender had not received appropriate treatment and management in the past and this operated to focus the sentence on rehabilitation.

Some courts have gone further and required a report setting out specific deficits and the linkage between those and the offence being sentenced for. The simple fact of a diagnosis is insufficient for judicial consideration (R. v. Joamie,2013 NUCJ 19, R. v. Hanksa, 2014 MBQB 184). The ABCA in Ramsay said that medical reports need to detail the deficits of an offender in a way that allows the court to address both his rehabilitation prospects and his moral culpability. Likewise in Joamie, the NUCJ refused to consider FASD as a mitigating factor in the absence of a report that linked the specific cognitive deficits of the offender to the offence and assessed the offender’s moral blameworthiness in the context those deficits. Also problematic for sentencing was the lack of an expert consideration of the risk of recidivism and available resources to reduce risk.

Also see Dangerous - Long Term Offender Designation caselaw.