Mood and anxiety disorders in patients with myasthenia gravis: aetiology, diagnosis and treatment.

Myasthenia gravis (MG) is a chronic, autoimmune disease involving neuromuscular junctions. It is frequently associated with symptoms such as loss of muscle strength, difficulty in respiration and swallowing, diplopia and ptosis. All chronic diseases, including MG, may have psychiatric consequences in terms of coping and adaptation. Psychiatric morbidity usually appears as anxiety disorders, such as panic disorder and generalised anxiety disorder, and as depressive disorders. However, there are very few data on the prevalence and aetiology of such psychiatric symptoms in patients with MG, and those available in the literature are generally from old studies with poor methodology. The interaction between MG and psychiatric disorders needs to be appreciated, especially in the primary care setting, since the symptoms may overlap. MG may be under-recognised initially because the psychiatric symptoms may coincide with those of the actual disease, such as fatigue, lack of energy and shortness of breath. On the other hand, co-morbid psychiatric symptoms that appear during the course of the illness may be misdiagnosed as true myasthenic symptoms; thus, leading to unnecessary drug treatment. Differentiation of the aetiology of these symptoms might alter the treatment choice and, therefore, affect the treatment success rate and patients' well-being. Psychiatric treatments must be carefully planned because of the risk of aggravating the underlying neurological disease. Even though there appears to be an intricate relationship between MG and psychiatric symptoms, there is very limited information on this subject. As such, prospective, randomised, controlled pharmaco/psychotherapy studies are needed to better direct the management of patients and, thus, improve quality of life during the course of the illness.