The progression of addictive disorders over time

The degree to which tolerance to a substance can develop over time differs between individuals, and between different substances.^[5] It is difficult to determine whether and to what degree tolerance to a substance may have occurred.^[5] However, laboratory tests can be helpful – for example, if a person has high blood levels of a substance whilst not simultaneously showing the characteristic patterns of intoxication from that substance, this may be evidence of developing tolerance.^[5]

Reference:
[1] American Addiction Centres. https://americanaddictioncenters.org/the-addiction-cycle. Accessed March 2022.

[3] Volkow ND, Koob GF, McLellan AT. Neurobiologic advances from the brain disease model of addiction. N Engl J Med 2016; 374 (4): 363–371.

[2] Herman MA, Roberto M. The addicted brain: understanding the neurophysiological mechanisms of addictive disorders. Front Integr Neurosci 2015; 9: 18.

[4] Limbrick-Oldfield EH, Mick I, Cocks RE, et al. Neural substrates of cue reactivity and craving in gambling disorder. Transl Psychiatry 2017; 7 (1): e992.

[5] American Psychiatric Association (APA). Diagnostic and Statistical Manual of Mental Disorders, 5th edition. American Psychiatric Association, 2013.