Yes, a long-standing pattern of deviant behaviour can be considered abnormal, but deviance alone is not sufficient. Abnormal behaviour is characterized by the 'four Ds': deviance, distress, dysfunction, and danger. Deviance refers to behaviour, thoughts, and emotions that differ markedly from a society's ideas of proper functioning and break societal norms.

However, serious questions have been raised about defining abnormality solely as a deviation from social norms, as it assumes normality is merely conformity. Therefore, another crucial criterion is whether the behaviour is maladaptive. If the long-standing deviant behaviour interferes with optimal functioning, growth, and the well-being of the individual or their group, it is considered abnormal. Thus, a deviant behaviour is abnormal if it is also distressing, dysfunctional, or dangerous.