The present invention is concerned with deuterium-enriched sulfonamides of formula 1, their pharmaceutically acceptable salts and methods of use thereof for the treatment of anxiety disorders including, General Anxiety Disorder (GAD), Panic Disorder (PD), Post-Traumatic Stress Disorder (PTSD), Social Phobia (SP), Health Anxiety (Hypochondriasis), depression, major depressive disorders, unipolar depression, bipolar I depression disorder, bipolar II depression disorder, treatment-resistant depression, single episodic and recurrent major depressive disorders, depression in the medically ill, attention deficit hyperactivity disorder (ADHD), attention deficit disorder (ADD), Obsessive-Compulsive Disorder (OCD), Obsessive-Compulsive Personality Disorder (OCPD), Autism Spectrum Disorder (ASD), schizophrenia, psychosis, epilepsy, seizures, hot flashes due to menopause, age-related macular degeneration (AMD), premature ejaculation, male erectile dysfunction, sexual dysfunction, obesity, eating disorders, bulimia nervosa, anorexia nervosa, angina, migraine, pain, nociception, sleep disorders, insomnia, fibromyalgia, alcohol withdrawal, autism, Rett's syndrome, cyclothymic disorder, neural injury, neurodegenerative diseases, Parkinson's disease, Parkinson's disease psychosis, Huntington disease, Alzheimer's disease, frontotemporal dementia, cognitive impairment associated with age-related dementia, Alzheimer's disease, schizophrenia, psychosis, depression, pain or discomfort associated with surgery and pain or discomfort associated with medical illness.