Unlike many other subjective effects, such as euphoria or anxiety, this effect does not actively induce specific emotions regardless of a person's current state of mind and mental stability. Instead, it works by passively amplifying and enhancing the genuine emotions that a person is already feeling prior to ingesting the drug or prior to the onset of this effect. This causes emotion intensification to be equally capable of manifesting in both a positive and negative direction.      This effect highlights the importance of set and setting when using psychedelics in a therapeutic context, especially if the goal is to produce a catharsis.   
For example, an individual who is currently feeling somewhat anxious or emotionally unstable may become overwhelmed with intensified negative emotions, paranoia, and confusion. In contrast, an individual who is generally feeling positive and emotionally stable is more likely to find themselves overwhelmed with states of emotional euphoria, happiness, and feelings of general contentment. The intensity of emotional states felt under this effect can shape the tone of a trip and predispose the user to other effects, such as mania or unity in positive states and thought loops or feelings of impending doom in negative states.  Intensely negative or difficult emotions may still arise in therapeutic contexts, however (with adequate support) people nevertheless view the experience positively due to the perceived value of integrating the emotional states' additional insight. 
Emotion intensification is most commonly induced under the influence of moderate dosages of psychedelic compounds, such as LSD, psilocybin, and mescaline.     However, it can also occur under the influence of cannabinoids, GABAergic depressants   , and stimulants   .
- Belser, Alexander B.; Agin-Liebes, Gabrielle; Swift, T. Cody; Terrana, Sara; Devenot, Neşe; Friedman, Harris L.; Guss, Jeffrey; Bossis, Anthony; Ross, Stephen (2017). "Patient Experiences of Psilocybin-Assisted Psychotherapy: An Interpretative Phenomenological Analysis". Journal of Humanistic Psychology. 57 (4): 354–388. | https://doi.org/10.1177/0022167817706884
- Kamboj, S. K., Joye, A., Bisby, J. A., Das, R. K., Platt, B., & Curran, H. V. (2013). Processing of facial affect in social drinkers: a dose–response study of alcohol using dynamic emotion expressions. Psychopharmacology, 227(1), 31-39. | https://doi.org/10.1007/s00213-012-2940-5
- Philippot, P., Kornreich, C., Blairy, S., Baert, I., Dulk, A. D., Bon, O. L., ... & Verbanck, P. (1999). Alcoholics’ deficits in the decoding of emotional facial expression. Alcoholism: Clinical and Experimental Research, 23(6), 1031-1038. | https://doi.org/10.1111/j.1530-0277.1999.tb04221.x
- Wardle, M. C., Garner, M. J., Munafò, M. R., & de Wit, H. (2012). Amphetamine as a social drug: effects of d-amphetamine on social processing and behavior. Psychopharmacology, 223(2), 199-210. | https://dx.doi.org/10.1007%2Fs00213-012-2708-y
-  Gasser, Peter; Kirchner, Katharina; Passie, Torsten (2014). "LSD-assisted psychotherapy for anxiety associated with a life-threatening disease: A qualitative study of acute and sustained subjective effects". Journal of Psychopharmacology. 29 (1): 57–68. | https://doi.org/10.1177%2F0269881114555249