Dr. Gaynor presents a thoroughly engaging lecture about Borderline Personality Disorder (BPD). The current working definition of BPD is ‘a pervasive disorder of the emotion regulation system’. Dr. Gaynor outlines how BPD presents differently to ‘normal’ depression and bipolar depression. He talks about common behaviours (addictions, self-harm, acting out) that some people engage in when attempting to regulate the emotional dysregulation caused by BPD. He addresses the reasons that BPD symptoms may develop for an individual and refers to three evidence based treatments: Dialectic Behavioural Therapy (DBT), Mentalisation and Schema Therapy. Dr. Gaynor also stresses the important contribution made by Margaret Linehan, who is considered the leading expert internationally in the field of BPD.