What illnesses often co-exist with bipolar disorder?

• Substance abuse is very common among people with bipolar disorder, but the reasons for this link are unclear.
• Some people with bipolar disorder may try to treat their symptoms with alcohol or drugs. 
• Substance abuse can also trigger or prolong bipolar symptoms, and the behavioral problems associated with mania can lead to drinking too much.
•  Anxiety disorders, such as post-traumatic stress disorder (PTSD) and social phobia, also can co-occur with bipolar disorder.
•  Bipolar disorder can co-occur with attention deficit hyperactivity disorder (ADHD) as well, which has some symptoms that overlap with bipolar disorder, such as restlessness and being easily distracted. However, the symptoms of ADHD are persistent, whereas those of bipolar disorder are episodic.
•  In addition, people with bipolar disorder are at higher risk for thyroid disease, migraine headaches, heart disease, diabetes, obesity, and other physical illnesses.
•  These illnesses may cause symptoms of mania or depression, or they may be caused by some medications used to treat bipolar disorder.