A 39-Year-Old Man With Diarrhea, Weight Loss, and Mood Shifts

Heidi Moawad, MD


May 22, 2023

Other disorders that can cause similar behavioral symptoms include attention-deficit/hyperactivity disorder, a depressive disorder, an anxiety disorder, and schizoaffective disorder. Some patients experience psychotic episodes in association with bipolar disorder, which can make it difficult to distinguish from schizoaffective disorder. Patients with bipolar disorder who seek treatment for symptoms of depression may initially receive a diagnosis of a depressive disorder, until the first signs of mania or hypomania emerge or become problematic.

If it is clear that a patient has a mood disorder that involves fluctuations between depressive episodes and features of mania, the next step is to differentiate between cyclothymic disorder, bipolar disorder type I, and bipolar disorder type II. The features of these conditions are [1]:

  • Bipolar I disorder: This condition is defined by manic episodes that last at least 7 days or that require hospitalization. Depressive episodes can occur. Episodes of depressive symptoms and manic symptoms at the same time are also possible. Having four or more episodes of mania or depression within a year is defined as "rapid cycling."

  • Bipolar II disorder: This condition includes depressive episodes and hypomanic episodes.

  • Cyclothymic disorder: This condition includes episodes of recurrent hypomanic and depressive symptoms that do not meet the criteria for hypomania or depression.

Although diagnostic criteria exist for each of these conditions, distinguishing between them is not always clear and can require participation from other people who spend time with the patient. According to the International Classification of Diseases, 11th Revision (ICD-11) and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), features that distinguish a hypomanic episode from a manic episode include a lack of marked functional impairment, no requirement for hospitalization, and the absence of psychotic symptoms in hypomania.[2]

Patients with bipolar disorder typically seek medical attention for depressive symptoms rather than for symptoms of mania or hypomania. However, some patients may experience harm due to behaviors or recklessness associated with mania, such as injuries. Examples of dangerous behaviors in persons with mania include overreaching business decisions, inappropriate sexual activities, and speeding. Additionally, family members, friends, and others who are concerned about the patient might be more alarmed about the symptoms associated with mania than the patient is.

The risk for bipolar disorder is considered multifactorial, with possible contributions of genetic and environmental factors. The risk is increased among patients who have a family history of depressive disorders or bipolar disorder,[1] but this correlation does not confirm whether the risk is associated with familial or environmental factors. Although changes in a number of different genes have been associated with an increased risk for bipolar disorder, no genetic test can rule in or rule out the condition.[1]

Brain imaging studies are not expected to show changes that can point to the diagnosis of bipolar disorder, but research studies suggest that there might be alterations in metabolism in different regions of the brain among patients who have bipolar disorder.[3] This finding does not establish whether the risk is due to genetic or environmental factors.

Changes in weight and gut microbiota can be associated with bipolar disorder. Both bipolar disorder and unipolar depression have been linked to an increased incidence of obesity.[4]

Recently, gut microbiome alterations have been noted with these two mood disorders. One study identified distinct gut microbial compositions in patients with major depressive disorder and bipolar disorder and found that these compositions differ from each other and from those in healthy controls. The researchers suggested that alterations in gut microbiota may alter lipid metabolism but did not directly correlate these changes with obesity or any particular pattern of weight fluctuations.[5]

Certain eating habits, including a lack of appetite and excessive eating, have been noted in patients with bipolar disorder and depressive disorders. These habits are more likely than gut microbial alterations to cause weight changes. Both of these mood disorders increase the risk for excessive weight gain or loss, which can result in either overweight or underweight. This patient's abdominal symptoms are unlikely to be associated with his bipolar disorder and seem to be directly correlated with his new diet.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.