Causes of Bipolar Disorder

While there are many biological factors associated with mania and depression, none of them has been proven to be a cause or to be diagnostic of bipolar disorder.<

At least 50 percent of people with bipolar disorder have a parent with a mood disorder, most often major depressive disorder. A person has a 30 percent chance of inheriting a mood disorder if one parent has bipolar disorder, and a 60 percent chance if both parents have it. Research has found an even greater risk among twins, especially identical twins, who have a parent with bipolar disorder.

New mothers with bipolar disorder have a great risk—30 to 50 percent—for an episode during the first month after childbirth. This means that the pregnancy must be managed properly to ensure safety for both mother and child.

Bipolar Disorder Signs and Symptoms

Mania Symptoms

Untreated symptoms of mania can last up to 3 months. Symptoms include the following:

  • Aggressive, provocative, and intrusive behavior
  • Belief in exaggerated or unrealistic abilities or powers
  • Decreased need for sleep
  • Denial that anything is wrong
  • Drug abuse, alcohol abuse
  • Easily irritated and distracted
  • Feeling extremely "high" or euphoric
  • Hyperactivity
  • Racing thoughts and rapid or pressured speech
  • Sustained period of uncharacteristic behavior
  • Uncharacteristically poor judgment
  • Unusually active sex drive

Delusions occur in 75 percent of manic episodes. In a delusional state, a person loses their perception of reality. For example, a person may believe they possess amazing strength and ability, are extremely wealthy, or are publicly desired. Auditory and visual hallucinations are common and can be dangerous.

Patients are at risk for injuring themselves or others during a manic state. In severe episodes, hospitalization may be necessary.

Depression Symptoms

After a manic episode, people with bipolar disorder may experience a symptom-free phase that can last for months. Eventually, a depressive episode ensues. Symptoms of depression include the following:

  • Anxiety
  • Guilt, hopelessness, worthlessness
  • Inability to concentrate, remember, or make decisions
  • Irritability
  • Lack of appetite and weight loss, or increased appetite and weight gain
  • Lack of interest or pleasure in usual activities, including sex
  • Loss of energy
  • Sadness
  • Sleep disturbance (i.e., too little, too much, or waking up and not being able to go back to sleep)
  • Thoughts and attempts of suicide

Mixed Episode Symptoms

During a mixed episode, both manic and depressive symptoms are experienced daily for at least 1 week. The person usually feels very anxious and disorganized and commonly will develop insomnia, psychosis, and loss of appetite.

A mixed episode can last from a week to several months and is usually followed by a depressive episode. They occur more often in people (especially men) under 25 and over 60 years of age. Mixed episodes are seen most frequently in teenagers who have experienced major depression.

Mixed episodes are severe and impair daily functioning in social interactions, occupational activity, and intimate relationships. In some cases, there are psychotic features or other symptoms that are so severe that hospitalization is necessary to prevent the patient from harming him- or herself or others.

When mixed episodes occur in children, especially those under 8 years of age, attention deficit disorder (ADD) should be considered, because ADD has similar symptoms, such as hyperactivity, elation, sudden sadness, and low self-esteem.

Rapid Cycling Symptoms of Bipolar Disorder

In rapid cycling there are more manic and depressive episodes of shorter duration, and they become more severe as the patient ages. Typically, four or more rapid-cycling episodes occur within 1 year.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Feb 2001

Last Modified: 31 Jul 2013