Table 1.
Clinical features of mania and rodent phenocopies of components of excessive behavioral excitement
| Domains | Clinical diagnostic features | Suitable animal tests |
Expected outcomes |
mCLOCK | GluR6 −/− |
ERK1 −/− |
|---|---|---|---|---|---|---|
| Mood | Elevated, expansive or irritable mood | Unknown | NA | NA | NA | NA |
| Thought | Inflated self-esteem or grandiosity | Unknown | NA | NA | NA | NA |
| Flight of ideas or racing thoughts | Unknown | NA | NA | NA | NA | |
| Behavior | More talkative than usual or pressure to keep talking | Unknown | NA | NA | NA | NA |
| Increase in goal-directed activity (either socially, at work or school or sexually) or psychomotor agitation | Open field test Novel object exploration | Increased investigation | Yes | Yes | Yes | |
| Social interaction test | Increased social interaction, constructive or destructive | No data | Yes | No data | ||
| Resident–intruder test | ||||||
| Mating activity | Increased sexual activity | No data | No data | No data | ||
| Sweetened solution preference test | Increased hedonic/pleasurable activity | Yes | Yes | Yes | ||
| Wheel running activity | ||||||
| FUST | ||||||
| CPP | ||||||
| ICSS | ||||||
| Forced swim or tail suspension tests | Increased escaping activity | Yes | Yes | Yes | ||
| Learned helplessness paradigm | ||||||
| Excessive involvement in pleasurable activities that have a high potential for painful consequences (e.g., engaging in unrestrained buying sprees, sexual indiscretions or foolish business investments) | Center activity in open field Elevated plus maze or zero maze Light/dark Reward/aversion test Novelty-induced hypophagia | More risk-taking (or less anxiety-like) activity | Yes | Yes | Yes | |
| Decreased need for sleep (e.g., feels rested after only 3 h of sleep) | Home cage activity monitoring | More activity and less rest in home cage | No data | Yes | Yes | |
| Home cage wheel running | ||||||
| Attention | Distractibility (i.e., attention too easily drawn to unimportant or irrelevant external stimuli) | There are potential tests, but these need to be further validated. | More distractible | No data | No data | No data |
| Exclusions | Manic symptoms are not due to neurological, endocrine or metabolic diseases | Brain morphology, biochemical tests and battery of motor-sensory tests | No obvious changes | Circadian dysfunction | Yes | Yes |
| Psychostimulant | Increased use | Psychostimulant-induced locomotion | No change or increased | Yes | Yes | Yes |
Abbreviations: CPP, conditioned place preference test; ERK1, extracellular signal-regulated kinase-1; FUST, female urine sniffing test; GluR6, glutamate receptor 6; ICSS, intracranial self-stimulation; NA, not applicable.