In BD, bipolar depression is characterized by increased striatal dopamine transporter levels, resulting in attenuated dopaminergic function (17).
Experts believe bipolar disorder is partly caused by an underlying problem with specific brain circuits and the functioning of brain chemicals called neurotransmitters. Three brain chemicals -- norepinephrine (noradrenaline), serotonin, and dopamine -- are involved in both brain and bodily functions.
The researchers say the evidence suggested a model where increased dopamine D2/3 receptor levels in the striatum would increase dopaminergic neurotransmission and lead to mania, while increased dopamine transporter (DAT) levels in the striatum would reduce dopaminergic function and cause depression.
One is that there are low concentrations of intrasynaptic serotonin in patients with bipolar disorder, thus facilitating serotonin transporter internalization. Deficits in synaptic serotonin may be consequent to alterations in binding of other neurotransmitters.
Research shows bipolar disorder may damage the brain over time. Experts think it's because you slowly lose amino acids. They help build the proteins that make up the insulation around your neurons.
Bipolar disorder is widely believed to be the result of chemical imbalances in the brain. The chemicals responsible for controlling the brain's functions are called neurotransmitters, and include noradrenaline, serotonin and dopamine.
MRIs and CT scans can provide detailed images of the brain and its structures. But currently, doctors don't use them to diagnose bipolar disorder. Detecting bipolar disorder is typically done through a diagnostic interview with a mental health professional.
The manic phase of bipolar disorder may include: feeling very happy, elated or overjoyed. talking very quickly. feeling full of energy.
The three main neurotransmitters that bipolar disorder may affect are: dopamine. serotonin. norepinephrine.
Risk factors
Factors that may increase the risk of developing bipolar disorder or act as a trigger for the first episode include: Having a first-degree relative, such as a parent or sibling, with bipolar disorder. Periods of high stress, such as the death of a loved one or other traumatic event. Drug or alcohol abuse.
Dopamine is most closely linked to positive symptoms of schizophrenia. Positive symptoms include: Hallucinations.
Having too much dopamine — or too much dopamine concentrated in some parts of the brain and not enough in other parts — is linked to being more competitive, aggressive and having poor impulse control. It can lead to conditions that include ADHD, binge eating, addiction and gambling.
Schizophrenia. Some symptoms of schizophrenia can possibly be caused by having too much dopamine in certain areas of your brain — delusions and hallucinations.
The researchers noted that that the cyclical quality of manic states in bipolar disorder “leads to a downregulation of dopamine receptor sensitivity (depression phase), which is later compensated by upregulation (manic state).”
Dopamine regulates mood and muscle movement and plays a vital role in the brain's pleasure and reward systems. The body stores the majority of serotonin in the gut. Serotonin helps regulate mood, body temperature, and appetite.
Low levels of dopamine have been linked to Parkinson's disease, restless legs syndrome and depression. Low levels of dopamine can make you feel tired, moody, unmotivated and many other symptoms.
In studies whose subjects include medicated, euthymic bipolar disorder patients, results indicate higher plasma GABA levels (17), but normal CSF (23) and brain GABA levels (19) when compared to controls.
The dopamine hypothesis of bipolar disorder proposes that faulty homoeostasis between dopamine transporter and receptors underlies depressive and manic phases of the illness.
These preliminary studies suggest that tyrosine availability to the brain attenuates pathological increases in dopamine neurotransmission following methamphetamine administration and putatively in mania.
A 2020 study suggests that nearly 23% of those with bipolar disorder could be considered high functioning. If you have high functioning bipolar disorder (HFBD), you might be able to manage your bipolar disorder symptoms and complete your daily responsibilities and functions.
Bipolar I disorder is the most severe form of the illness. Bipolar II disorder is characterized by predominantly depressive episodes accompanied by occasional hypomanic episodes. Hypomanic episodes are milder than manic episodes but can still impair functioning.
There are no specific blood tests or brain scans to diagnose bipolar disorder. Even so, a doctor may perform a physical exam and order lab tests, including a thyroid function test and urine analyses. These tests can help determine if other conditions or factors could be causing your symptoms.
To diagnose bipolar disorder, a doctor performs a physical exam, asks about your symptoms, and recommends blood testing to determine if another condition, such as hypothyroidism, is causing your symptoms. If the doctor does not find an underlying cause of your symptoms, he or she performs a psychological evaluation.
Bipolar disorder is frequently inherited, with genetic factors accounting for approximately 80% of the cause of the condition. 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.