The 5-year study, conducted by John Curry, a professor of psychology and neuroscience at Duke University, involved nearly 200 adolescents at 11 sites across the United States.
The researchers found that of the 192 teenagers whose depression receded after 12 weeks of treatment, only 10% abused drugs later on vs. 25% of adolescents who didn’t respond to treatment.
Curry explained: “It turned out that whatever they responded to – cognitive behavioral therapy, Prozac, both treatments, or a placebo – if they did respond within 12 weeks they were less likely to develop a drug-use disorder.”
The team followed nearly half of the 439 participants from the “Treatment for Adolescents with Depression Study” (TADS). The study was conducted from 2000 to 2003 and was led by Dr. John March, chief of Child and Adolescent Psychiatry at Duke University Medical Center.
At the end of Curry’s 5-year follow up, participants were aged 17 to 23 and had no previous problems with drug or alcohol abuse.
In the “Onset of Alcohol or Substance Use Disorders Following Treatment for Adolescent Depression” (2004-2005), researchers found that 76% of study participants used marijuana. Other drugs included opiates, hallucinogens, and cocaine.
Before study participants received treatment, they must have had at least 5 symptoms for a length of time in order to be diagnosed with major depression. Symptoms included:
- Poor concentration
- Worthlessness
- Loss of interest
- Depressed mood
- Disruptions in appetite
- Loss of sleep or energy
- Suicidal thought of behavior
However, the team found no differences in alcohol abuse. Curry believes that this may partially be due to the prevalence of alcohol use among individuals aged 17 to 23.
Curry explained:
“It does point out that alcohol use disorders are very prevalent during that particular age period and there’s a need for a lot of prevention and education for college students to avoid getting into heavy drinking and then the beginnings of an alcohol disorder. I think that is definitely a take-home message.”
The team also found that participants who consumed alcohol were more likely to have repeat bouts with depression.
Curry said:
“When the teenagers got over the depression, about half of them stayed well for the whole five-year period, but almost half of them had a second episode of depression. And what we found out was that, for those who had both alcohol disorder and another depression, the alcohol disorder almost always came first.”
According to Curry and co-author Susan Silva, associate professor and statistician in the Duke School of Nursing, further studies are required as the number of individuals who developed drug or alcohol disorders was fairly small. Furthermore, the team were unable to determine whether the rates of subsequent drug or alcohol abuse were higher among teenagers who didn’t receive treatment for depression as this study had no comparison group of non-depressed patients.
Written By Grace Rattue