About Process/Behavioral Addictions
Donovan and Marlatt (1988) in their book on assessing addictive behaviors indicate that addicitons aren't defined by the focus of the addiciton (i.e. drugs) but by the process that addictions have in common including eating disorders, ganbling, drug addiciton, etc. Some are addictions to behaviors and others are addicitons to substances. However, they arll involve an addictive process.
Zhang, Tian, von Deneen, Liu & Gold (2012) Neuropsychiatry
"the addict shows loss of control, an inability ot stop or modify the activity, and a range of signs and symptoms that can be as debilitating as those associated with substance abuse or addiciton (p. 156).
Behavioral or process addictions consume the addicts thoughts and time. The addict feels compelled to engaging in planning for or engaging in the behavior to which he/she is addicted. They utilize the behavior to avoid anxiety or negative emotional states and often feel aggitated or angry if they are unable to engage in the behavior. There is significant impairment or functional consequences regarding problems in interpersonal relationships, difficulties at work/school, and disengagement in other activities he/she once found enjoyable or activities he/she is expected to engage in as part of his/her participation in a family/relationship/co-worker/student,etc.
There are some fMRI studies that indicate that the same neurological processes involving the reward pathways in the brain that are implicated in substance addictions are also involved in behavioral addicitons. The American Psychiatric Association in the DSM 5 now acknowledges the existence of this data and of behavioral/process addicitons. The American Society of ADdictive Medicine (ASAM) has included process additions in its' definition of addiction for some time: http://www.asam.org/for-the-public/definition-of-addiciton.