Competency to Stand Trial Expert Witness
Counsel retain a competency to stand trial expert witness for one reason: to learn whether the defendant can understand the proceedings and rationally assist in his own defense right now. Dr. Mendonsa conducts those evaluations for the defense, for the prosecution, and on appointment by the court.
Competency to stand trial is a present-tense question. Under Dusky v. United States, 362 U.S. 402 (1960), the defendant must have sufficient present ability to consult with counsel with a reasonable degree of rational understanding, and a rational as well as factual understanding of the proceedings. His mental state at the time of the offense is a separate question.
A competency to stand trial expert witness is asked for one thing: a present-tense opinion a court can check. The constitutional floor is Dusky v. United States, 362 U.S. 402 (1960): whether the defendant has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding, and whether he has a rational as well as factual understanding of the proceedings against him. Drope v. Missouri, 420 U.S. 162 (1975), supplies the trigger and its duration — a court must inquire when the evidence raises a bona fide doubt, and the duty continues through trial.
California codifies that floor. Penal Code § 1367 bars trying, sentencing, or revoking supervision for a defendant who, as a result of a mental health disorder or developmental disability, cannot understand the proceedings or assist counsel in a rational manner. When a judge states a doubt on the record, § 1368 requires inquiry of defense counsel and suspension of the criminal prosecution once the question is ordered determined, though § 1368.1 lets a demurrer or a § 1538.5 motion go forward where it can be fairly decided without the defendant. Under § 1369 the court appoints at least one licensed psychologist or psychiatrist; the defendant is presumed competent, and incompetence must be proved by a preponderance of the evidence.
Restoration, and the clock on it
For felonies, Penal Code § 1370 controls. The treating facility reports to the court within 90 days of commitment, and the commitment cannot run past two years from the date of commitment or the maximum term of imprisonment for the most serious charged offense, whichever is shorter. Misdemeanors run on a separate track under § 1370.01, which points the court toward diversion, a CARE Act or assisted outpatient referral, conservatorship, or dismissal rather than hospitalization. Where the underlying disorder is treatable, mental health diversion under Penal Code § 1001.36 is often the more useful route: it requires a DSM diagnosis that was a significant factor in the charged offense, runs up to two years on a felony and one year on a misdemeanor, and ends in dismissal on successful completion.
Competency is not criminal responsibility
This is the most common confusion in a criminal file. Competency is about the defendant now. Criminal responsibility is about the defendant then. California tries an insanity plea separately under Penal Code § 1026, and the standard in § 25(b) is a M’Naghten formulation: the accused must prove by a preponderance of the evidence that he was incapable of knowing or understanding the nature and quality of his act and of distinguishing right from wrong. A defendant can be floridly psychotic at the offense and competent at arraignment, or the reverse. The two opinions rest on different data and should never be blended.
Adjacent capacities get their own analysis. A Miranda waiver must be voluntary and made with full awareness of the right abandoned and the consequences of abandoning it (Moran v. Burbine, 475 U.S. 412 (1986)), and mental illness alone does not make a statement involuntary without coercive police conduct (Colorado v. Connelly, 479 U.S. 157 (1986)). Self-representation is a higher bar still: Indiana v. Edwards, 554 U.S. 164 (2008), permits a state to insist on counsel for a defendant competent to stand trial but not competent to conduct that trial alone.
What the evaluation actually measures.
Each prong of the legal standard is assessed against data, and the presentation itself is tested rather than assumed.
The Two Dusky Prongs, Separately
Factual and rational understanding of the charges, pleas, roles, and consequences is scored apart from present ability to work with counsel. A defendant who can recite the courtroom cast and still cannot track his own case fails the second prong and passes the first.
Understanding · AssistingFeigned Symptoms
Incompetence is an easy thing to claim and a hard thing to sustain under structured questioning. Formal response-style measures are administered on every case, not only where malingering is suspected, so the finding means something either way.
SIRS-2 · MMPI-3 · PAIFeigned Cognitive Impairment
Claimed amnesia and claimed intellectual limitation call for performance validity testing rather than clinical impression. Effort is measured directly before any cognitive score is interpreted.
TOMMCognitive and Memory Capacity
Where the deficit appears genuine, the question becomes how far it reaches. Intellectual and memory testing shows whether the defendant can hold and use case information across the span of a trial day.
WAIS-V · WMS-VDevelopmental Disability
Penal Code § 1370.1 routes defendants with developmental disabilities differently from those with mental health disorders. Adaptive functioning is measured, not inferred from IQ alone.
Vineland · ABASSafety and Restoration Planning
Suicide risk and mood severity are screened in every custodial evaluation, and the report states what treatment would plausibly restore this defendant rather than gesturing at restoration in the abstract.
C-SSRS · BDI · BAIFrom the first call to the witness stand.
A competency file moves fast, so the sequence is built to produce a usable report before the next calendar date.
Scope call and conflict check
Fifteen minutes to fix the referral question, the jurisdiction, the statutory posture, and the deadline. If the real question is criminal responsibility, diversion eligibility, or a sentencing mitigation issue rather than present competence, that gets said on the first call and the scope is written accordingly.
Records before the interview
Charging documents, police reports, jail medical and mental health records, custody incident logs, prior evaluations, medication administration records, school and military records where relevant, and counsel’s own account of what the defendant is and is not able to do. An examination without the file produces an impression, not an opinion.
Examination
A structured competency interview covering both prongs, a mental status examination, and standardized testing selected for the specific question. Response style is tested in every case. If the defendant is medicated, the effect of the medication on his current presentation is documented rather than set aside.
Formulation against the legal standard
Findings are mapped to the elements of Penal Code § 1367 and to the Dusky prongs, one at a time, with the basis for each conclusion stated. Where the data are equivocal, the report says so and explains what additional information would resolve it.
Report
Sources relied on, procedures administered, validity findings, clinical findings, and the opinion on each statutory element. Where incompetence is found, the report addresses whether competence is likely to be restored in the foreseeable future and what treatment that would take.
Deposition, hearing, testimony
Preparation with counsel, direct and cross, and rebuttal analysis of an opposing evaluator’s report where the opinions diverge. The opinion given on the stand is the opinion in the report.
The background this opinion rests on.
Competency work rewards evaluators who have seen the systems that defendants are actually sent to.
Competency questions counsel ask before retaining.
What is the legal standard for competency to stand trial?
Dusky v. United States, 362 U.S. 402 (1960), sets the federal constitutional standard: whether the defendant has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding, and whether he has a rational as well as factual understanding of the proceedings against him. Drope v. Missouri, 420 U.S. 162 (1975), holds that a court must inquire whenever the evidence raises a bona fide doubt, and that the duty persists during trial.
California states the same rule in Penal Code § 1367, tied to a mental health disorder or a developmental disability. Under § 1369 the defendant is presumed competent and incompetence must be shown by a preponderance of the evidence. A diagnosis by itself proves nothing; the opinion has to connect the impairment to one of the two abilities the statute names.
How is competency to stand trial different from an insanity defense?
Competency is about the defendant now. Legal insanity is about the defendant at the moment of the offense. They are separate inquiries, tried at different times, on different records.
In California the insanity plea is tried separately under Penal Code § 1026, and the substantive standard in Penal Code § 25(b) is a M’Naghten formulation: the accused must prove by a preponderance of the evidence that he was incapable of knowing or understanding the nature and quality of his act and of distinguishing right from wrong. A defendant can meet that standard and still be fully competent to stand trial, and a defendant can be incompetent today with no viable insanity defense at all. Asking one evaluator for one report covering both, without separating the data, is how these opinions get impeached.
What happens after a defendant is found incompetent, and how long can restoration take?
Criminal proceedings stay suspended. For a felony, Penal Code § 1370 governs: the court considers whether restoration is in the interests of justice, the treating facility must report to the court within 90 days of commitment, and the commitment cannot exceed two years from the date of commitment or the maximum term of imprisonment for the most serious charged offense, whichever is shorter.
Misdemeanors follow Penal Code § 1370.01, which directs the court toward mental health diversion, a CARE Act or assisted outpatient treatment referral, a conservatorship referral, or dismissal rather than a hospital commitment. Because these provisions have been amended repeatedly, the current text should be checked against the posture of the specific case.
Can you tell whether a defendant is malingering incompetence?
Not with certainty, and no honest evaluator claims otherwise. What can be done is to test the presentation formally instead of relying on clinical intuition, which performs poorly at this task.
That means structured measures of reported symptoms, personality inventories with built-in validity scales, and performance validity testing where cognitive or memory impairment is claimed. Feigned incompetence tends to look different from genuine incompetence in patterned ways: over-endorsement of rare or improbable symptoms, inconsistency between claimed impairment and observed behavior in custody, and failure on effort measures that genuinely impaired defendants routinely pass. The report states what was administered and what the results support, including when they support nothing.
My client was found competent but wants to represent himself. Is that the same question?
No. Indiana v. Edwards, 554 U.S. 164 (2008), holds that the Constitution does not forbid a state from insisting on representation by counsel for a defendant who is competent enough to stand trial but who suffers from severe mental illness to the point of not being competent to conduct trial proceedings himself.
That is a separate evaluation with a different focus: organizing a defense, following a trial calendar, managing courtroom conduct, and making strategic decisions under pressure, rather than simply understanding what is happening.
Can you evaluate whether a Miranda waiver was knowing and intelligent?
Yes, and it is a distinct capacity from trial competence. A valid waiver has to be voluntary in the sense of a free and deliberate choice, and made with full awareness of the nature of the right being abandoned and the consequences of abandoning it (Moran v. Burbine, 475 U.S. 412 (1986)).
The limit is worth knowing before the motion is filed. Under Colorado v. Connelly, 479 U.S. 157 (1986), coercive police activity is a necessary predicate to a finding that a confession was involuntary; a defendant’s mental condition on its own does not dispose of the voluntariness question. The useful psychological work is usually on the knowing-and-intelligent prong — reading level, intellectual functioning, suggestibility, and comprehension of the specific warning language used.
Send the file. You will get a straight answer on scope.
Charging documents, jail records, and the next court date are enough for an initial read on whether a competency evaluation is the right tool.