Yes, an accused in a Hyderabad criminal case can challenge the mental fitness of the complainant as a witness, but this must be done through proper legal procedure rather than casual assertion, since Indian evidence law places a strong presumption in favour of a witness's competence unless proven otherwise. Under the Bharatiya Sakshya Adhiniyam, which governs evidence, every person is presumed competent to testify unless the court considers that the person is prevented from understanding the questions put to them or from giving rational answers because of tender age, extreme old age, disease of the body or mind, or any similar cause.

The proper way to raise this challenge is not simply to allege incompetence in argument, but to request the trial court to conduct a preliminary voir dire examination of the witness before their testimony is recorded, so the judge can independently assess whether the complainant understands the nature of an oath and can give rational, coherent answers. If there is documented psychiatric history, prior medical records, or credible expert opinion suggesting impairment, this can be placed before the court to support the request for such an examination, or in appropriate cases, for a formal medical evaluation of fitness to testify.

It is important to understand that even where a witness has some cognitive or psychiatric condition, this does not automatically disqualify their testimony — courts have held that partial impairment goes to the weight and reliability of the evidence rather than its admissibility altogether, provided the witness is able to communicate coherently, even if through assistance or an interpreter. This means a successful challenge requires more than raising doubt; it requires demonstrating that the complainant genuinely cannot understand questions or give rational answers.

Raising this issue tactically and at the right stage of trial is important, because doing so too aggressively without a strong evidentiary foundation can backfire and appear to the court as an attempt to intimidate or discredit a genuine victim. This is a delicate line, and getting the strategy right with the help of Aapka Legal Advice before you file any application on mental fitness can significantly improve how the court perceives your case.

Because challenges to a complainant's competence touch both criminal procedure and medical evidence, they require lawyers skilled in cross-examination and expert evidence handling. The Top Criminal Lawyers in Hyderabad | Aapka Legal Advice team, in consultation with our panel of retired judges experienced in evidentiary matters, can help assess whether your case has a genuine basis for such a challenge and how best to present it in court. If you are defending a case in Hyderabad and have legitimate concerns about a complainant's mental fitness as a witness, professional legal guidance is essential to raise the issue effectively and credibly.