Studies of neurocognitive function in bipolar disorder indicate deficits in three core domains: attention, executive function, and emotional processing.
Bipolar disorder may reduce gray matter volume
Gray matter contributes in some way to every aspect of human life. A 2016 meta-analysis found a significantly lower volume of gray matter in the brains of people with bipolar disorder compared with those of people without the condition.
Bipolar disorder can change specific areas of the brain, including its gray matter and hippocampus. Researchers have connected these changes to specific symptoms such as impulsivity, but the connection still isn't clear-cut.
Structural Differences
Studies have shown reduced gray matter in people with bipolar, and these deficits are most pronounced in the areas of the brain controlling inhibition and motivation—frontal and temporal regions.
The relationship between high IQ and bipolar disorder isn't causative. “But the genes that cause bipolar disorder and the genes that cause high intelligence may in some cases go together,” says Tohen.
The bipolar states of mania and depression have a clear impact on cognitive function. The clinical criteria for mania include distractibility, inappropriate speech and behavior, increased goal-directed behavior, and a tendency to make decisions associated with potential painful consequences.
Bipolar disorder often runs in families, and research suggests this is mostly explained by heredity—people with certain genes are more likely to develop bipolar disorder than others. Many genes are involved, and no one gene can cause the disorder.
The cause of BPAD is uncertain, but we know more today than we did a decade ago. Three brain chemicals — norepinephrine, serotonin, and dopamine — are involved in psychiatric disorders. Norepinephrine and serotonin are linked to mood disorders, such as depression and BPAD.
Likewise, symptoms may slow productivity and strain relationships with coworkers. People with bipolar disorder may also be more prone to face discrimination in the workplace. However, discrimination against bipolar disorder is illegal, and there are resources to protect you.
Bipolar disorder seems to often run in families and there appears to be a genetic part to this mood disorder. There is also growing evidence that environment and lifestyle issues have an effect on the disorder's severity.
Scientists have suggested that some people with bipolar disorder experience memory problems due to changes in the brain. These could involve changes in: The prefrontal cortex, which plays a role in planning, attention, problem-solving, and memory, among other functions.
An episode of mania may impact your psychomotor skills, reasoning, and working memory. Sometimes, you may also experience psychosis. But research shows that despite these neurocognitive impairments, intelligence in people with bipolar disorder is not impacted by the onset of the condition.
A child of one parent with bipolar disorder and one without has a 15% to 30% chance of having BP. If both parents have bipolar disorder, there's a 50% to 75% chance that a child of theirs will, too. If you already have one child with BP, there is a 15% to 25% chance that another of your children will also have it.
Bipolar disorder is the most likely psychiatric disorder to be passed down from family. If one parent has bipolar disorder, there's a 10% chance that their child will develop the illness. If both parents have bipolar disorder, the likelihood of their child developing bipolar disorder rises to 40%.
There is some evidence that bipolar disorder may be associated with chemical imbalances in the brain. The chemicals responsible for controlling the brain's functions are called neurotransmitters, and include noradrenaline, serotonin and dopamine.
Bipolar disorder has been linked to various structural brain changes, including most notably progressive grey matter loss in the brain's frontal regions.
Schizophrenia & Bipolar Are Neurobiological Disorders - The Evidence : Mental Illness Policy Org.
Findings are based upon CAT scans, MRIs, and MRS scans. While no brain scan currently in use can definitively diagnose someone with bipolar, scans are helpful in ruling out other diagnoses and in research.
Bipolar disorder can cause a lack of empathy, but symptoms may also make it more challenging to focus on the feelings of others. While there is no medication to improve empathy, treating bipolar disorder can help. Introspection, guided emotional learning, and observing emotions in others may also help build empathy.
Bipolar mania can speed up a person's thinking processes, and the person may feel as if they cannot get the words out fast enough to express their thoughts. A person with bipolar disorder may experience pressured speech during manic periods. These are periods of extreme highs.
In other words, experiencing bipolar disorder does not mean you can't tell right from wrong, but its symptoms can temporarily make it harder to let our sense of morality guide our actions.