In bipolar depression imaging studies show increased dopamine transporter levels, but changes in other aspects of dopaminergic function are inconsistent.
In BD, bipolar depression is characterized by increased striatal dopamine transporter levels, resulting in attenuated dopaminergic function (17).
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).”
Norepinephrine and serotonin are linked to mood disorders, such as depression and BPAD. Dopamine, is more closely linked to psychotic disorders, such as schizophrenia. However, since these disorders have a number of symptoms in common, all three chemicals are likely involved in different phases of BPAD.
Dopamine, more than other neurotrans-mitters, has been implicated in the transition of depression to a manic episode in bipolar disorder [19].
Low levels of serotonin are associated with depression and low mood. People with bipolar disorder having a depressive episode may experience: low energy. suicidal thoughts.
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.
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.
The findings on dopamine in mood disorders suggest that decreased dopamine activity is involved in depression, while increased dopamine function contributes to mania.
Dopaminergic modulators
These agents increase dopaminergic neurotransmission and are thought to be useful in the treatment of depressive episodes in bipolar disorder, but not in the context of other psychiatric conditions. They are also being tested for mania symptoms.
Mental health conditions like ADHD, addiction, depression, schizophrenia, and OCD are also linked to dopamine disorders. High dopamine symptoms include anxiety, excessive energy, insomnia, and 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.
Dopamine deficiency can affect your physical and mental health. Many medical conditions are linked to low levels of dopamine, including Parkinson's disease, restless legs syndrome, depression, schizophrenia and attention deficit hyperactivity disorder (ADHD). Treatments are available to manage these conditions.
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.
Mood stabilizers, including lithium and VPA, exhibit therapeutic effects on the dopaminergic system. Lithium could modulate downstream dopamine receptors in postsynaptic dopaminergic signal transduction by acting through the AKT/GSK3 signaling cascade [Reference Malhi, Tanious, Das, Coulston and Berk31].
No two people with bipolar disorder share the same thoughts or experiences, but there are some common thought patterns among most folks who have it. This includes cyclical thinking, manic and/or depressive episodes, suicidal ideation, and psychosis.
The results showed that manic episodes led to decreased volume in certain areas of the brain. Bipolar disorder has been linked to various structural brain changes, including most notably progressive grey matter loss in the brain's frontal regions.
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.
Dopamine hyperactivity in brain regions linked to reward-related motivation, such as the nucleus accumbens (NCC) and prefrontal cortex, also leads to increases in impulsive and aggressive behavior (see reviews by Everitt & Robbins, 2000; Friedel, 2004).
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 moods and symptoms. We all have changes in our mood, but in bipolar disorder these changes can feel very distressing and have a big impact on your life. You may feel that your high and low moods are extreme, and that swings in your mood are overwhelming.
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.
Bipolar makes us feel things in extremes—and often causes us to be labeled as “too intense” or “too sensitive.”