[1][2][3] DDM can be caused by psychiatric disorders like depression and schizophrenia, brain injuries, strokes, and neurodegenerative diseases.
[3][8][4] Diminished motivation can also be induced by certain drugs, including antidopaminergic agents like antipsychotics,[9][10][4][11] selective serotonin reuptake inhibitors (SSRIs),[12][13] and cannabis, among others.
[1][2][3][4] A multitude of terms have been used to refer to DDM of varying severities and varieties, including apathy, abulia, akinetic mutism, athymhormia, avolition, amotivation, anhedonia, psychomotor retardation, affective flattening, akrasia, and psychic akinesia (auto-activation deficit or loss of psychic self-activation), among others.
[7] Less extreme forms of DDM, for instance apathy or anhedonia, can be a symptom of psychiatric disorders and related conditions, like depression, schizophrenia, or drug withdrawal.
[42][43] Genetic variants in catechol-O-methyltransferase (COMT) have been associated with motivation and apathy susceptibility,[42][44][45][46][47] as well as with reward, mood, and other neuropsychological variables.
[19][53][54][55][56][57][58] It appears that continually increasing or ascending concentration–time curves are beneficial for prolonging effects, which has resulted in administration multiple times per day and development of delayed- and extended-release formulations.
[59][60][61][62][63][64] Besides medications, various psychological and physiological processes, including arousal,[65] mood,[66][67][68][69][70] expectancy effects (e.g., placebo),[71][72] novelty,[73][74] psychological stress or urgency,[75][76][65] rewarding and aversive stimuli,[65] availability of rewards,[77] addiction,[78] and sleep amount,[79] among others, can also context- and/or stimulus-dependently modulate or enhance brain dopamine signaling and motivation to varying degrees.
[84][85][86][87] However, ADHD has perhaps more accurately been conceptualized as a disorder of executive function and of directing or allocating attention and motivation rather than a global deficiency in these processes.
[90][82] In any case, as with management of DDM, psychostimulants and other catecholaminergic agents are used in people with ADHD to treat their symptoms, including difficulties with attention, executive control, and motivation, and are clinically effective for such purposes.