Definitions of outcomes*
| Off-label use | |
| Concurrent use | Use of inhaler and cigarettes at least several times a week for one month |
| Non-cessation use | Use to reduce smoking or use in situation where cannot smoke for one month |
| Harmful use | |
| Damage to health (ICD-10) | Use caused or made health problem worse |
| Continued use (ICD-10) | Used for ⩾1 month despite harm |
| Dependence | |
| Tolerance (DSM-IV and ICD-10) | Increasing use of cartridge to obtain similar effect or diminishing effect with repeated use |
| Withdrawal (DSM-IV and ICD-10) | Four withdrawal symptoms rated as moderate or severe or using cartridge to avoid or relieve withdrawal symptoms |
| Compulsive use (ICD-10) | Craving or strong desire to use |
| Use more than intended (DSM-IV and ICD-10) | Probes for loss of control |
| Unsuccessful efforts to cut down or stop (DSM-IV and ICD-10) | ⩾2 failed attempts |
| Use despite harm (DSM-IV and ICD-10) | Attribute harm to inhaler and continue use |