Following the ICD-10 Diagnostic guidelines [1], a definite diagnosis of carbon dependence should usually be made only if three or more of the following have been present together at some time during the previous year:

1.    A strong desire or sense of compulsion to take the substance.

e.g. compulsive upgrading of mobile phone or other functioning electronic goods; overwhelming desire for overseas weekend-break.

2.    Difficulties in controlling substance-taking behaviour in terms of its onset, termination, or levels of use.

e.g. failed attempts to cycle to work; inability to use up contents of veg box in preference to buying new food.

3.    A physiological withdrawal state when substance use has ceased or been reduced.

e.g. experience of anxiety on public holidays without ready access to shops; disproportionate rage at rises in fuel price. 

4.    Evidence of tolerance, such that increased doses of the psychoactive substance are required in order to achieve effects originally produced by lower doses.

e.g. diminished duration and intensity of euphoria experienced on making a purchase; ever increasing distance travelled to reach same number of destinations:
 

Sustrans graph - data from National Travel Survey

5.    Progressive neglect of alternative pleasures or interests because of psychoactive substance use, increased amount of time necessary to obtain or take the substance or to recover from its effects.

e.g. working longer hours to augment income at the expense of leisure and family time; progressive atrophy of skills and interests outside shopping and television-watching.

6.    Persisting with substance use despite clear evidence of overtly harmful consequences; efforts should be made to determine that the user was actually, or could be expected to be, aware of the nature and extent of the harm.

It is important to check that your patient is aware of the harmful effects of global warming and the relationship to their own carbon habit.