Recent Ruling Continues Trend of Restricting a Trial Court’s Ability to Reject Mental Health Diversion Eligibility When it is Supported by a Qualified Expert Opinion
In the evolving landscape of criminal justice reform, California courts continue to expand the application of the mental health diversion statute. The 2026 ruling in Siam v. Superior Court offers critical insights into eligibility and suitability criteria under Penal Code section 1001.36. This ruling underscores the importance of evidence-based evaluations in prioritizing treatment over incarceration for individuals with mental health disorders and rejects the trial court’s ability to deny diversion based on unsubstantiated allegations.
As attorneys dedicated to advocating for clients facing such challenges, we at Lessem, Newstat & Tooson, LLP believe this case provides valuable guidance for defendants, legal professionals, and the broader community. We also believe this decision underscores the value California law places on treatment and rehabilitation over incarceration.
Summary of the Case and the 2026 Update
The case of Siam v. Superior Court originated from charges against petitioner Joel Praneet Siam stemming from a March 2022 incident in Newport Beach, California. Siam, who was experiencing a manic episode related to bipolar disorder, damaged a vehicle at a car dealership and subsequently stole a yacht, leading to a collision that injured another individual. Prior to this, Siam had a history of mental health issues, including a 2020 offense in San Diego involving an assault during a paranoid episode, for which he was initially granted diversion but later revoked following the Newport Beach events.
Siam sought pretrial mental health diversion under Penal Code section 1001.36, supported by evaluations from multiple mental health experts. These included a psychiatrist who diagnosed him with paranoid schizophrenia in partial remission and a psychologist who later identified bipolar disorder as the primary condition, attributing his actions to undermedication and misdiagnosis. The experts opined that Siam’s symptoms would respond to treatment, including medication and therapy, and that he posed a low risk of recidivism with proper support.
The trial court denied the motion in September 2024, deeming Siam eligible but unsuitable due to concerns over his responsiveness to treatment and potential danger to public safety. Siam petitioned for a writ of mandate, arguing an abuse of discretion. On January 26, 2026, the Court of Appeal of the State of California, Fourth Appellate District, granted the petition in part, issuing a writ to vacate the denial and remand the case for reconsideration.
This 2026 opinion builds on amendments to section 1001.36, particularly the 2023 change to subdivision (b)(2), which requires courts to presume a mental disorder was a significant factor in the offense unless clear and convincing evidence proves otherwise. The decision clarifies procedural and evidentiary standards, emphasizing reliance on qualified mental health experts and substantial evidence for any findings of unsuitability.
Major Takeaways from Siam v. Superior Court
The Siam ruling has far-reaching implications for mental health diversion in California, promoting a more rehabilitative approach within the criminal justice system.
Key highlights include:
- Emphasis on Expert Opinions: The court reinforced that determinations of whether a defendant’s symptoms would respond to treatment must be based solely on the opinions of qualified mental health experts, such as psychiatrists or psychologists. Trial courts cannot override these opinions without challenging the experts’ credentials or the premises of their evaluations. This protects against subjective judicial assessments and ensures decisions are grounded in clinical expertise.
- Substantial Evidence Requirement for Dangerousness: In evaluating whether a defendant poses an unreasonable risk to public safety if treated in the community, courts must rely on substantial evidence. The appellate court critiqued the trial court’s reliance on unsubstantiated claims, such as a purported history of treatment refusal, which were contradicted by evidence of compliance and voluntary interventions. Factors like prior offenses during untreated or misdiagnosed states cannot automatically preclude diversion, especially when experts attest to low future risk under appropriate care.
- Broad Application of Diversion: Aligning with the legislative intent of section 1001.36, to mitigate criminal justice involvement through treatment, the decision limits residual judicial discretion. It encourages granting diversion where eligibility and suitability criteria are met, unless it clearly fails to serve public safety or rehabilitative goals. This is particularly relevant for non-violent or low-risk offenses linked to mental health conditions, potentially reducing recidivism and incarceration rates.
- Procedural Safeguards: The ruling mandates thorough consideration of all criteria, including consent to diversion, waiver of speedy trial rights, and agreement to treatment compliance. It also highlights the role of informal evidence in prima facie showings, making the process more accessible while maintaining rigor.
Overall, Siam v. Superior Court signals a further shift toward evidence-driven, compassionate justice, ensuring mental health diversion is not unduly restricted by misconceptions about past behaviors or offense severity.
How Lessem, Newstat & Tooson, LLP Helps Clients with Mental Health-Related Cases
At Lessem, Newstat & Tooson, LLP, we specialize in navigating the complexities of criminal cases involving mental health issues. Our experienced attorneys understand the nuances of California’s diversion programs and work tirelessly to secure outcomes that prioritize rehabilitation over punishment.
Here’s how we assist clients:
- Comprehensive Case Evaluation: We begin by thoroughly reviewing your case, including medical history and expert assessments, to determine eligibility for mental health diversion. We build strong arguments emphasizing how your condition contributed to the alleged offense and how treatment can lead to positive change.
- Expert Collaboration: We partner with qualified mental health professionals to obtain detailed evaluations that support diversion motions. Our team ensures these opinions are robust and aligned with statutory requirements, countering any opposition from prosecutors.
- Strategic Advocacy: Whether negotiating with district attorneys or litigating in court, we advocate for suitability based on substantial evidence, highlighting factors like family support, treatment compliance, and low recidivism risk. If a denial occurs, we pursue appeals or writs to challenge abuses of discretion.
- Holistic Support: Beyond legal representation, we connect clients with resources for ongoing treatment, including therapy, medication management, and community programs. Our goal is not just case resolution but long-term stability and reintegration.
If you or a loved one is facing charges complicated by mental health challenges, our firm is here to provide personalized, effective representation. Contact us today to discuss your options.