Females with ADHD more likely to smoke than males
Subtype and gender of attention deficit hyperactivity disorder (ADHD) differentially impact smoking initiation and escalation, a recent study suggests.
“The association of inattention with smoking in female adolescents may be causal, whereas hyperactivity-impulsivity appears to act indirectly through shared propensities for both ADHD and smoking,” the investigators said.
More severe ADHD symptoms during childhood were associated with smoking initiation and smoking at a younger age in adolescents. The association of ADHD symptoms with daily smoking, nicotine dependence and number of cigarettes per day was more pronounced in females than in males.
Furthermore, monozygotic female twins with more severe attentional problems than their co-twins had higher nicotine involvement. This was consistent with possible causal influence. After considering co-occurring externalizing behaviours and stimulant medication, the said effects persisted.
On the other hand, it appeared that hyperactivity-impulsivity was primarily noncausal even as it was more strongly associated to smoking for female adolescents.
The investigators used twin difference methods to control for shared genetic and environmental confounders in three population-based, same-sex twin sample (n=3,762; 64 percent monozygotic). One cohort oversampled female adolescents with ADHD beginning in childhood.
Smoking outcomes by age 17 years was predicted by performing regressions of childhood inattentive and hyperactive-impulsive symptoms. ADHD effects were grouped into those shared between twins in the pair and those nonshared, or different within pairs.
In one study, researchers found that hyperactivity/impulsivity was a predictor of later substance problems, while inattention alone posed less risk. Furthermore, even a single symptom of ADHD or conduct disorder correlated with elevated risk. [Arch Gen Psychiatry 2007;64:1145-1152]