Oblivious and hypervigilant
The psychiatrist and psychoanalyst Glen Gabbard described two subtypes of NPD in 1989, later referred to as equivalent to, the grandiose and vulnerable subtypes. The first was the "oblivious" subtype of narcissist, equivalent to the grandiose subtype. It was described as being grandiose, arrogant and thick-skinned, while also exhibiting personality traits of helplessness and emotional emptiness, low self-esteem and shame. These were observed in people with NPD to be expressed as socially avoidant behavior in situations where self-presentation is difficult or impossible, leading to withdrawal from situations where social approval is not given. The second subtype Gabbard described was termed "hypervigilant", equivalent to the vulnerable subtype. People with this subtype of NPD were described as having easily hurt feelings, an oversensitive temperament, and persistent feelings of shame. High functioning or exhibitionist
A third subtype for classifying people with NPD, also initially theorised by Gabbard, is termed high functioning or exhibitionistic. It has been described as "high functioning narcissists [who] were grandiose, competitive, attention-seeking, and sexually provocative; they tended to show adaptive functioning and utilize their narcissistic traits to succeed." Millons subtypes
In the study Disorders of Personality: DSM-IV-TM and Beyond (1996), Theodore Millon suggested five subtypes of NPD, although they did not identify specific treatments per subtype. Mastersons subtypes (exhibitionist and closet)
In 1993, James F. Masterson proposed two subtypes for pathological narcissism, exhibitionist and closet. Both fail to adequately develop an age- and phase- appropriate self because of defects in the quality of psychological nurturing provided, usually by the mother.
Therefore, in patients with COPD and significant degrees of clubbing, a search for signs of bronchogenic carcinoma (or other causes of clubbing) might still be indicated. A congenital form has also been recognized. Hypertrophic pulmonary osteoarthropathy
A special form of clubbing is hypertrophic pulmonary osteoarthropathy (HPOA), known in continental Europe as Pierre Marie-Bamberger syndrome. This is the combination of clubbing and thickening of periosteum (connective tissue lining of the bones) and synovium (lining of joints), and is often initially diagnosed as arthritis. It is commonly associated with lung cancer. Primary hypertrophic osteoarthropathy
Primary hypertrophic osteoarthropathy is HPOA without signs of pulmonary disease. This form has a hereditary component, although subtle cardiac abnormalities can occasionally be found. It is known eponymously as the Touraine–Solente–Golé syndrome. This condition has been linked to mutations in the gene on the fourth chromosome (4q33-q34) coding for the enzyme 15-hydroxyprostaglandin dehydrogenase (HPGD); this leads to decreased breakdown of prostaglandin E2 and elevated levels of this substance. Pathogenesis
The exact cause for sporadic clubbing is unknown. Theories as to its cause include:

Vasodilation (i.e., distended blood vessels). Secretion of growth factors (e.g., platelet-derived growth factor and hepatocyte growth factor) from the lungs. Overproduction of prostaglandin E2 by other tissues. Increased entry of megakaryocytes into the systemic circulation. Under normal circumstances in healthy individuals, megakaryocytes that arise from the bone marrow are trapped in the pulmonary capillary bed and broken down before they enter the systemic circulation.