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.
Associated disorders
A single manic episode, in the absence of secondary causes, (i.e., substance use disorders, pharmacologics, or general medical conditions) is often sufficient to diagnose bipolar I disorder. Hypomania may be indicative of bipolar II disorder. Manic episodes are often complicated by delusions and/or hallucinations; and if the psychotic features persist for a duration significantly longer than the episode of typical mania (two weeks or more), a diagnosis of schizoaffective disorder is more appropriate. Certain obsessive-compulsive spectrum disorders as well as impulse control disorders share the suffix "-mania," namely, kleptomania, pyromania, and trichotillomania. Despite the unfortunate association implied by the name, however, no connection exists between mania or bipolar disorder and these disorders. Furthermore, evidence indicates a B12 deficiency can also cause symptoms characteristic of mania and psychosis.Hyperthyroidism can produce similar symptoms to those of mania, such as agitation, elevated mood, increased energy, hyperactivity, sleep disturbances and sometimes, especially in severe cases, psychosis.