that underlie mental and behavioral functioning. These disturbances are usually associated with distress or impairment in personal, family, social, educational, occupational, or other important areas of functioning'. This Chapter has 161 categories recognized as diseases of psychiatric origin. These categories are enlisted under twenty blocks. Some of the blocks which may be relevant to Forensic Mental Health in the context of criminal administration of justice are: Neuro-developmental disorders, Schizophrenia, Catatonia, Mood disorders, Anxiety or related fear disorders, Obsessive compulsive disorders, Disorders associated with stress, Dissociative disorders, Disorders due to substance use or addictive behaviors, Impulse control disorders, Disruptive behavior or dissocial disorders, Personality disorders, Paraphilic disorders, Factitious disorders, Neuro-cognitive disorders, Mental and behavioral disorders associated with pregnancy and puerperium, Secondary mental and behavioral disorders due to other diseases. 36. The term "mental disorder" has also been defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) published in 2013, as under:"A mental disorder is a syndrome characterized by clinically significant disturbance in an individual's cognition, emotion Regulation, or behavior that reflects a dysfunction in the psychological, biological, or developmental processes underlying mental functioning. Mental disorders are usually associated with significant distress or disability in social, occupational, or other important activities. An expectable or culturally approved response to a common stressor or loss, such as the death of a loved one, is not a mental disorder. Socially deviant behavior (e.g. political, religious, or sexual) and conflicts that are primarily between the individual and society are not mental disorders unless the deviance or conflict results from a dysfunction in the individual, as described above." 37. An examination of the definitions for mental illness provided for in the domestic and foreign laws establishes the fact that the terms "mental illness" or "mental disorder" are both used to refer to mental ailments and are defined by medical science. It is with the developing nature of medical science that scope of these terms may also evolve. Therefore, we are of the view that a limited definition of the terms "mental disorder" or "mental illness" should be avoided, and the Provincial Legislatures may, in order to better appreciate the evolving nature of medical science, consider to appropriately amend the relevant provisions of mental health laws to cater for medically recognized mental and behavioral disorders as notified by WHO through its latest edition of ICD. It has been noted that the evolution of medical science and human rights has sensitized the society to stigmatic labels such as "unsound mind", "lunatic" and "insane". Latest legislations all over the world do not use such terms. Therefore, we consider it appropriate to direct that the terms "unsoundness of mind" and "unsound mind" occurring in P.P.C., Cr.P.C. and the Prison Rules be substituted with term "mental disorder" or "mental illness". The term "lunatic" wherever occurs shall also be substituted appropriately. 38. We now proceed to address the question "How should the trial Court deal with the plea of an accused that he/she was suffering from mental illness at the time