The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders is often referred to as the ‘psychiatric bible’, being used extensively by clinicians to make psychiatric diagnosis. However, since DSM is a set of constructs, many current criteria sets fail to capture real illnesses. While diagnostic systems seem to help understand how to categorise and respond to mental illnesses, this isn’t the case always. At times, this becomes a purely academic exercise divorced from clinical reality. Also, in some patients, using psychiatric diagnosis does not aid treatment decisions. Here, we are presenting three cases to debate about the place, role and impact of diagnosis using DSM in managing psychiatric patients in clinical practice. CONCLUSION There are many cases in clinical practice that may have significant psychopathology or have subthreshold symptoms but may not fulfil the diagnostic criteria laid down by DSM-5. In such cases it is warranted that a clinical approach be followed and treatment started in the light of a clinical evidence of psychopathology and treatment should not be withheld due to lack of a DSM diagnosis. Though DSM plays an extensive role in classifying psychopathology, the above cases illustrate the lacunae in this classification system. Mental health professionals have used DSM to diagnose mental illnesses since decades but unfortunately this is fraught with problems as it is unable to encompass the wide range of individual variations seen in clinical practice.