In stages II and III mania, however, the patient may be extraordinarily irritable, psychotic or even delirious. These latter two stages are referred to as acute and delirious (or Bells), respectively. Causes
Various triggers have been associated with switching from euthymic or depressed states into mania. One common trigger of mania is antidepressant therapy. Studies show that the risk of switching while on an antidepressant is between 6-69 percent. Dopaminergic drugs such as reuptake inhibitors and dopamine agonists may also increase risk of switch. Other medication possibly include glutaminergic agents and drugs that alter the HPA axis. Lifestyle triggers include irregular sleep-wake schedules and sleep deprivation, as well as extremely emotional or stressful stimuli.Various genes that have been implicated in genetic studies of bipolar have been manipulated in preclinical animal models to produce syndromes reflecting different aspects of mania. CLOCK and DBP polymorphisms have been linked to bipolar in population studies, and behavioral changes induced by knockout are reversed by lithium treatment. Metabotropic glutamate receptor 6 has been genetically linked to bipolar, and found to be under-expressed in the cortex. Pituitary adenylate cyclase-activating peptide has been associated with bipolar in gene linkage studies, and knockout in mice produces mania like-behavior. Targets of various treatments such as GSK-3, and ERK1 have also demonstrated mania like behavior in preclinical models.Mania may be associated with strokes, especially cerebral lesions in the right hemisphere.Deep brain stimulation of the subthalamic nucleus in Parkinsons disease has been associated with mania, especially with electrodes placed in the ventromedial STN.
While limited, some studies demonstrate manipulation of PKC in animals produces behavioral changes mirroring mania, and treatment with PKC inhibitor tamoxifen (also an anti-estrogen drug) demonstrates antimanic effects. Traditional antimanic drugs also demonstrate PKC inhibiting properties, among other effects such as GSK3 inhibition.Manic episodes may be triggered by dopamine receptor agonists, and this combined with tentative reports of increased VMAT2 activity, measured via PET scans of radioligand binding, suggests
a role of dopamine in mania. Decreased cerebrospinal fluid levels of the serotonin metabolite 5-HIAA have been found in manic patients too, which may be explained by a failure of serotonergic regulation and dopaminergic hyperactivity.Limited evidence suggests that mania is associated with behavioral reward hypersensitivity, as well as with neural reward hypersensitivity. Electrophysiological evidence supporting this comes from studies associating left frontal EEG activity with mania. As left frontal EEG activity is generally thought to be a reflection of behavioral activation system activity, this is thought to support a role for reward hypersensitivity in mania. Tentative evidence also comes from one study that reported an association between manic traits and feedback negativity during receipt of monetary reward or loss. Neuroimaging evidence during acute mania is sparse, but one study reported elevated orbitofrontal cortex activity to monetary reward, and another study reported elevated striatal activity to reward omission. The latter finding was interpreted in the context of either elevated baseline activity (resulting in a null finding of reward hypersensitivity), or reduced ability to discriminate between reward and punishment, still supporting reward hyperactivity in mania.