Amphetamine use and co-occurring psychological problems: Review of the literature and implications for treatment

There has been a substantial increase in the use of amphetamine in Australia in recent years, with many users presenting with a range of psychological symptoms including those associated with mood, anxiety and psychotic disorders. Many of these symptoms are due to the direct effect of amphetamine or occur during withdrawal and resolve rapidly. However, determining whether there is a pre-existing disorder requires a careful assessment of the temporal relationship between the onset of regular drug use and symptoms, and ideally ongoing monitoring of symptoms in the absence of drug use. Treatment options need to match the diagnostic presentation, and drawing from the limited literature in this area it is recommended that amphetamine use be targeted in the first instance and other more intensive treatments follow as the diagnostic picture becomes clearer. Many people use psychostimulants and, although the majority who use occasionally by non-injecting routes of administration do not experience problems (Hall, Darke, Ross, & Wodak, 1993), it appears that as many as 30% of amphetamine users develop a psychostimulant use disorder (Hall, Teesson, Lynskey, & Degenhardt, 1998). Of particular concern is the recent increase in the use of methamphetamine across Australia (Topp, Day, & Degenhardt, 2003), a synthetic drug closely related to amphetamine but with higher abuse potential. It produces euphoric effects that are similar to, but longer lasting than those of, cocaine (Dean, 2004), with some evidence suggesting that the progression from initial use to regular and problematic use occurs more rapidly than with cocaine use (Castro, Barrington, Walton, & Rawson, 2000). There are many indications (e.g., increased availability of methamphetamine, an increasing trend towards injection, an increase in demand for treatment and reports of additional demands for emergency services) that the increase in methamphetamine use in Australia in the last 5 years will continue (Jenner & McKetin, 2004). There are now a number of studies in which the range of psychological symptoms have been documented among amphetamine users including depressed mood, anxiety, irritability, paranoia, mood swings, difficulty concentrating, aggression, hallucinations and psychosis (Topp et al., 2003). It would appear that many of these symptoms are related to the use of amphetamine and abate on cessation of use. Cross-sectional studies have suggested that perhaps up to half of regular amphetamine users report that these symptoms emerge after the commencement of regular amphetamine use (Baker et al., submitted; Hall, Hando, Darke, & Ross, 1996). However, it is possible that some symptoms may have pre-dated the use of amphetamine and may be related to the initial use of the substance. The risk of experiencing adverse effects of amphetamine appears to be related to dose, with the risk of harm reduced with less than twice weekly use and the use of small amounts (Hall & Hando, 1994). In this paper we review the literature describing the prevalence and course of the most common co-occurring psychological problems among amphetamine users. A review of treatments currently considered to be best practice will be provided and recommendations for further research suggested